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David Matlack [Wed, 16 Nov 2022 20:42:28 +0000 (12:42 -0800)]
KVM: selftests: Check for KVM nEPT support using "feature" MSRs
When checking for nEPT support in KVM, use kvm_get_feature_msr() instead
of vcpu_get_msr() to retrieve KVM's default TRUE_PROCBASED_CTLS and
PROCBASED_CTLS2 MSR values, i.e. don't require a VM+vCPU to query nEPT
support.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20220927165209.930904-1-dmatlack@google.com
[sean: rebase on merged code, write changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Sean Christopherson [Thu, 6 Oct 2022 00:51:25 +0000 (00:51 +0000)]
KVM: selftests: Drop helpers for getting specific KVM supported CPUID entry
Drop kvm_get_supported_cpuid_entry() and its inner helper now that all
known usage can use X86_FEATURE_*, X86_PROPERTY_*, X86_PMU_FEATURE_*, or
the dedicated Family/Model helpers. Providing "raw" access to CPUID
leafs is undesirable as it encourages open coding CPUID checks, which is
often error prone and not self-documenting.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-13-seanjc@google.com
Sean Christopherson [Thu, 6 Oct 2022 00:51:24 +0000 (00:51 +0000)]
KVM: selftests: Add and use KVM helpers for x86 Family and Model
Add KVM variants of the x86 Family and Model helpers, and use them in the
PMU event filter test. Open code the retrieval of KVM's supported CPUID
entry 0x1.0 in anticipation of dropping kvm_get_supported_cpuid_entry().
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-12-seanjc@google.com
Sean Christopherson [Thu, 6 Oct 2022 00:51:23 +0000 (00:51 +0000)]
KVM: selftests: Add dedicated helpers for getting x86 Family and Model
Add dedicated helpers for getting x86's Family and Model, which are the
last holdouts that "need" raw access to CPUID information. FMS info is
a mess and requires not only splicing together multiple values, but
requires doing so conditional in the Family case.
Provide wrappers to reduce the odds of copy+paste errors, but mostly to
allow for the eventual removal of kvm_get_supported_cpuid_entry().
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-11-seanjc@google.com
Sean Christopherson [Thu, 6 Oct 2022 00:51:22 +0000 (00:51 +0000)]
KVM: selftests: Add PMU feature framework, use in PMU event filter test
Add an X86_PMU_FEATURE_* framework to simplify probing architectural
events on Intel PMUs, which require checking the length of a bit vector
and the _absence_ of a "feature" bit. Add helpers for both KVM and
"this CPU", and use the newfangled magic (along with X86_PROPERTY_*)
to clean up pmu_event_filter_test.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-10-seanjc@google.com
Sean Christopherson [Thu, 6 Oct 2022 00:51:21 +0000 (00:51 +0000)]
KVM: selftests: Convert vmx_pmu_caps_test to use X86_PROPERTY_*
Add X86_PROPERTY_PMU_VERSION and use it in vmx_pmu_caps_test to replace
open coded versions of the same functionality.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-9-seanjc@google.com
Sean Christopherson [Thu, 6 Oct 2022 00:51:20 +0000 (00:51 +0000)]
KVM: selftests: Convert AMX test to use X86_PROPRETY_XXX
Add and use x86 "properties" for the myriad AMX CPUID values that are
validated by the AMX test. Drop most of the test's single-usage
helpers so that the asserts more precisely capture what check failed.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-8-seanjc@google.com
Sean Christopherson [Thu, 6 Oct 2022 00:51:19 +0000 (00:51 +0000)]
KVM: selftests: Add kvm_cpu_*() support for X86_PROPERTY_*
Extent X86_PROPERTY_* support to KVM, i.e. add kvm_cpu_property() and
kvm_cpu_has_p(), and use the new helpers in kvm_get_cpu_address_width().
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-7-seanjc@google.com
Sean Christopherson [Thu, 6 Oct 2022 00:51:18 +0000 (00:51 +0000)]
KVM: selftests: Refactor kvm_cpuid_has() to prep for X86_PROPERTY_* support
Refactor kvm_cpuid_has() to prepare for extending X86_PROPERTY_* support
to KVM as well as "this CPU".
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-6-seanjc@google.com
Sean Christopherson [Thu, 6 Oct 2022 00:51:17 +0000 (00:51 +0000)]
KVM: selftests: Use X86_PROPERTY_MAX_KVM_LEAF in CPUID test
Use X86_PROPERTY_MAX_KVM_LEAF to replace the equivalent open coded check
on KVM's maximum paravirt CPUID leaf.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-5-seanjc@google.com
Sean Christopherson [Thu, 6 Oct 2022 00:51:16 +0000 (00:51 +0000)]
KVM: selftests: Add X86_PROPERTY_* framework to retrieve CPUID values
Introduce X86_PROPERTY_* to allow retrieving values/properties from CPUID
leafs, e.g. MAXPHYADDR from CPUID.0x80000008. Use the same core code as
X86_FEATURE_*, the primary difference is that properties are multi-bit
values, whereas features enumerate a single bit.
Add this_cpu_has_p() to allow querying whether or not a property exists
based on the maximum leaf associated with the property, e.g. MAXPHYADDR
doesn't exist if the max leaf for 0x8000_xxxx is less than 0x8000_0008.
Use the new property infrastructure in vm_compute_max_gfn() to prove
that the code works as intended. Future patches will convert additional
selftests code.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-4-seanjc@google.com
Sean Christopherson [Thu, 6 Oct 2022 00:51:15 +0000 (00:51 +0000)]
KVM: selftests: Refactor X86_FEATURE_* framework to prep for X86_PROPERTY_*
Refactor the X86_FEATURE_* framework to prepare for extending the core
logic to support "properties". The "feature" framework allows querying a
single CPUID bit to detect the presence of a feature; the "property"
framework will extend the idea to allow querying a value, i.e. to get a
value that is a set of contiguous bits in a CPUID leaf.
Opportunistically add static asserts to ensure features are fully defined
at compile time, and to try and catch mistakes in the definition of
features.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-3-seanjc@google.com
Sean Christopherson [Thu, 6 Oct 2022 00:51:14 +0000 (00:51 +0000)]
KVM: selftests: Add X86_FEATURE_PAE and use it calc "fallback" MAXPHYADDR
Add X86_FEATURE_PAE and use it to guesstimate the MAXPHYADDR when the
MAXPHYADDR CPUID entry isn't supported.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006005125.680782-2-seanjc@google.com
David Matlack [Wed, 2 Nov 2022 18:46:54 +0000 (11:46 -0700)]
KVM: selftests: Add a test for KVM_CAP_EXIT_ON_EMULATION_FAILURE
Add a selftest to exercise the KVM_CAP_EXIT_ON_EMULATION_FAILURE
capability.
This capability is also exercised through
smaller_maxphyaddr_emulation_test, but that test requires
allow_smaller_maxphyaddr=Y, which is off by default on Intel when ept=Y
and unconditionally disabled on AMD when npt=Y. This new test ensures
that KVM_CAP_EXIT_ON_EMULATION_FAILURE is exercised independent of
allow_smaller_maxphyaddr.
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20221102184654.282799-11-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
David Matlack [Wed, 2 Nov 2022 18:46:53 +0000 (11:46 -0700)]
KVM: selftests: Expect #PF(RSVD) when TDP is disabled
Change smaller_maxphyaddr_emulation_test to expect a #PF(RSVD), rather
than an emulation failure, when TDP is disabled. KVM only needs to
emulate instructions to emulate a smaller guest.MAXPHYADDR when TDP is
enabled.
Fixes:
39bbcc3a4e39 ("selftests: kvm: Allows userspace to handle emulation errors.")
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20221102184654.282799-10-dmatlack@google.com
[sean: massage comment to talk about having to emulate due to MAXPHYADDR]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Sean Christopherson [Wed, 2 Nov 2022 18:46:52 +0000 (11:46 -0700)]
KVM: selftests: Provide error code as a KVM_ASM_SAFE() output
Provide the error code on a fault in KVM_ASM_SAFE(), e.g. to allow tests
to assert that #PF generates the correct error code without needing to
manually install a #PF handler. Use r10 as the scratch register for the
error code, as it's already clobbered by the asm blob (loaded with the
RIP of the to-be-executed instruction). Deliberately load the output
"error_code" even in the non-faulting path so that error_code is always
initialized with deterministic data (the aforementioned RIP), i.e to
ensure a selftest won't end up with uninitialized consumption regardless
of how KVM_ASM_SAFE() is used.
Don't clear r10 in the non-faulting case and instead load error code with
the RIP (see above). The error code is valid if and only if an exception
occurs, and '0' isn't necessarily a better "invalid" value, e.g. '0'
could result in false passes for a buggy test.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20221102184654.282799-9-dmatlack@google.com
Sean Christopherson [Wed, 2 Nov 2022 18:46:51 +0000 (11:46 -0700)]
KVM: selftests: Avoid JMP in non-faulting path of KVM_ASM_SAFE()
Clear R9 in the non-faulting path of KVM_ASM_SAFE() and fall through to
to a common load of "vector" to effectively load "vector" with '0' to
reduce the code footprint of the asm blob, to reduce the runtime overhead
of the non-faulting path (when "vector" is stored in a register), and so
that additional output constraints that are valid if and only if a fault
occur are loaded even in the non-faulting case.
A future patch will add a 64-bit output for the error code, and if its
output is not explicitly loaded with _something_, the user of the asm
blob can end up technically consuming uninitialized data. Using a
common path to load the output constraints will allow using an existing
scratch register, e.g. r10, to hold the error code in the faulting path,
while also guaranteeing the error code is initialized with deterministic
data in the non-faulting patch (r10 is loaded with the RIP of
to-be-executed instruction).
Consuming the error code when a fault doesn't occur would obviously be a
test bug, but there's no guarantee the compiler will detect uninitialized
consumption. And conversely, it's theoretically possible that the
compiler might throw a false positive on uninitialized data, e.g. if the
compiler can't determine that the non-faulting path won't touch the error
code.
Alternatively, the error code could be explicitly loaded in the
non-faulting path, but loading a 64-bit memory|register output operand
with an explicitl value requires a sign-extended "MOV imm32, r/m64",
which isn't exactly straightforward and has a largish code footprint.
And loading the error code with what is effectively garbage (from a
scratch register) avoids having to choose an arbitrary value for the
non-faulting case.
Opportunistically remove a rogue asterisk in the block comment.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20221102184654.282799-8-dmatlack@google.com
David Matlack [Wed, 2 Nov 2022 18:46:50 +0000 (11:46 -0700)]
KVM: selftests: Copy KVM PFERR masks into selftests
Copy KVM's macros for page fault error masks into processor.h so they
can be used in selftests.
Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221102184654.282799-7-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
David Matlack [Wed, 2 Nov 2022 18:46:49 +0000 (11:46 -0700)]
KVM: x86/mmu: Use BIT{,_ULL}() for PFERR masks
Use the preferred BIT() and BIT_ULL() to construct the PFERR masks
rather than open-coding the bit shifting.
No functional change intended.
Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221102184654.282799-6-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
David Matlack [Wed, 2 Nov 2022 18:46:48 +0000 (11:46 -0700)]
KVM: selftests: Move flds instruction emulation failure handling to header
Move the flds instruction emulation failure handling code to a header
so it can be re-used in an upcoming test.
No functional change intended.
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20221102184654.282799-5-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
David Matlack [Wed, 2 Nov 2022 18:46:47 +0000 (11:46 -0700)]
KVM: selftests: Delete dead ucall code
Delete a bunch of code related to ucall handling from
smaller_maxphyaddr_emulation_test. The only thing
smaller_maxphyaddr_emulation_test needs to check is that the vCPU exits
with UCALL_DONE after the second vcpu_run().
Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221102184654.282799-4-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
David Matlack [Wed, 2 Nov 2022 18:46:46 +0000 (11:46 -0700)]
KVM: selftests: Explicitly require instructions bytes
Hard-code the flds instruction and assert the exact instruction bytes
are present in run->emulation_failure. The test already requires the
instruction bytes to be present because that's the only way the test
will advance the RIP past the flds and get to GUEST_DONE().
Note that KVM does not necessarily return exactly 2 bytes in
run->emulation_failure since it may not know the exact instruction
length in all cases. So just assert that
run->emulation_failure.insn_size is at least 2.
Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221102184654.282799-3-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
David Matlack [Wed, 2 Nov 2022 18:46:45 +0000 (11:46 -0700)]
KVM: selftests: Rename emulator_error_test to smaller_maxphyaddr_emulation_test
Rename emulator_error_test to smaller_maxphyaddr_emulation_test and
update the comment at the top of the file to document that this is
explicitly a test to validate that KVM emulates instructions in response
to an EPT violation when emulating a smaller MAXPHYADDR.
Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221102184654.282799-2-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Gautam Menghani [Mon, 17 Oct 2022 17:58:19 +0000 (23:28 +0530)]
KVM: selftests: Don't assume vcpu->id is '0' in xAPIC state test
In xapic_state_test's test_icr(), explicitly skip iterations that would
match vcpu->id instead of assuming vcpu->id is '0', so that IPIs are
are correctly sent to non-existent vCPUs.
Suggested-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/kvm/YyoZr9rXSSMEtdh5@google.com
Signed-off-by: Gautam Menghani <gautammenghani201@gmail.com>
Link: https://lore.kernel.org/r/20221017175819.12672-1-gautammenghani201@gmail.com
[sean: massage shortlog and changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Vishal Annapurve [Tue, 15 Nov 2022 21:38:45 +0000 (21:38 +0000)]
KVM: selftests: Add arch specific post vm creation hook
Add arch specific API kvm_arch_vm_post_create to perform any required setup
after VM creation.
Suggested-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Reviewed-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Vishal Annapurve <vannapurve@google.com>
Link: https://lore.kernel.org/r/20221115213845.3348210-4-vannapurve@google.com
[sean: place x86's implementation by vm_arch_vcpu_add()]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Vishal Annapurve [Tue, 15 Nov 2022 21:38:44 +0000 (21:38 +0000)]
KVM: selftests: Add arch specific initialization
Introduce arch specific API: kvm_selftest_arch_init to allow each arch to
handle initialization before running any selftest logic.
Suggested-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Reviewed-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Vishal Annapurve <vannapurve@google.com>
Link: https://lore.kernel.org/r/20221115213845.3348210-3-vannapurve@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Vishal Annapurve [Tue, 15 Nov 2022 21:38:43 +0000 (21:38 +0000)]
KVM: selftests: move common startup logic to kvm_util.c
Consolidate common startup logic in one place by implementing a single
setup function with __attribute((constructor)) for all selftests within
kvm_util.c.
This allows moving logic like:
/* Tell stdout not to buffer its content */
setbuf(stdout, NULL);
to a single file for all selftests.
This will also allow any required setup at entry in future to be done in
common main function.
Link: https://lore.kernel.org/lkml/Ywa9T+jKUpaHLu%2Fl@google.com
Suggested-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Reviewed-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Vishal Annapurve <vannapurve@google.com>
Link: https://lore.kernel.org/r/20221115213845.3348210-2-vannapurve@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Sean Christopherson [Thu, 6 Oct 2022 00:45:12 +0000 (00:45 +0000)]
KVM: selftests: Play nice with huge pages when getting PTEs/GPAs
Play nice with huge pages when getting PTEs and translating GVAs to GPAs,
there's no reason to disallow using huge pages in selftests. Use
PG_LEVEL_NONE to indicate that the caller doesn't care about the mapping
level and just wants to get the pte+level.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006004512.666529-8-seanjc@google.com
Sean Christopherson [Thu, 6 Oct 2022 00:45:11 +0000 (00:45 +0000)]
KVM: selftests: Use vm_get_page_table_entry() in addr_arch_gva2gpa()
Use vm_get_page_table_entry() in addr_arch_gva2gpa() to get the leaf PTE
instead of manually walking page tables.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006004512.666529-7-seanjc@google.com
Sean Christopherson [Thu, 6 Oct 2022 00:45:10 +0000 (00:45 +0000)]
KVM: selftests: Use virt_get_pte() when getting PTE pointer
Use virt_get_pte() in vm_get_page_table_entry() instead of open coding
equivalent code.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006004512.666529-6-seanjc@google.com
Sean Christopherson [Thu, 6 Oct 2022 00:45:09 +0000 (00:45 +0000)]
KVM: selftests: Verify parent PTE is PRESENT when getting child PTE
Verify the parent PTE is PRESENT when getting a child via virt_get_pte()
so that the helper can be used for getting PTEs/GPAs without losing
sanity checks that the walker isn't wandering into the weeds.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006004512.666529-5-seanjc@google.com
Sean Christopherson [Thu, 6 Oct 2022 00:45:08 +0000 (00:45 +0000)]
KVM: selftests: Remove useless shifts when creating guest page tables
Remove the pointless shift from GPA=>GFN and immediately back to
GFN=>GPA when creating guest page tables. Ignore the other walkers
that have a similar pattern for the moment, they will be converted
to use virt_get_pte() in the near future.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006004512.666529-4-seanjc@google.com
Sean Christopherson [Thu, 6 Oct 2022 00:45:07 +0000 (00:45 +0000)]
KVM: selftests: Drop reserved bit checks from PTE accessor
Drop the reserved bit checks from the helper to retrieve a PTE, there's
very little value in sanity checking the constructed page tables as any
will quickly be noticed in the form of an unexpected #PF. The checks
also place unnecessary restrictions on the usage of the helpers, e.g. if
a test _wanted_ to set reserved bits for whatever reason.
Removing the NX check in particular allows for the removal of the @vcpu
param, which will in turn allow the helper to be reused nearly verbatim
for addr_gva2gpa().
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006004512.666529-3-seanjc@google.com
Sean Christopherson [Thu, 6 Oct 2022 00:45:06 +0000 (00:45 +0000)]
KVM: selftests: Drop helpers to read/write page table entries
Drop vm_{g,s}et_page_table_entry() and instead expose the "inner"
helper (was _vm_get_page_table_entry()) that returns a _pointer_ to the
PTE, i.e. let tests directly modify PTEs instead of bouncing through
helpers that just make life difficult.
Opportunsitically use BIT_ULL() in emulator_error_test, and use the
MAXPHYADDR define to set the "rogue" GPA bit instead of open coding the
same value.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006004512.666529-2-seanjc@google.com
Colin Ian King [Wed, 28 Sep 2022 21:34:58 +0000 (22:34 +0100)]
KVM: selftests: Fix spelling mistake "begining" -> "beginning"
There is a spelling mistake in an assert message. Fix it.
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Link: https://lore.kernel.org/r/20220928213458.64089-1-colin.i.king@gmail.com
[sean: fix an ironic typo in the changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Peter Gonda [Thu, 6 Oct 2022 00:34:09 +0000 (00:34 +0000)]
KVM: selftests: Add ucall pool based implementation
To play nice with guests whose stack memory is encrypted, e.g. AMD SEV,
introduce a new "ucall pool" implementation that passes the ucall struct
via dedicated memory (which can be mapped shared, a.k.a. as plain text).
Because not all architectures have access to the vCPU index in the guest,
use a bitmap with atomic accesses to track which entries in the pool are
free/used. A list+lock could also work in theory, but synchronizing the
individual pointers to the guest would be a mess.
Note, there's no need to rewalk the bitmap to ensure success. If all
vCPUs are simply allocating, success is guaranteed because there are
enough entries for all vCPUs. If one or more vCPUs are freeing and then
reallocating, success is guaranteed because vCPUs _always_ walk the
bitmap from 0=>N; if vCPU frees an entry and then wins a race to
re-allocate, then either it will consume the entry it just freed (bit is
the first free bit), or the losing vCPU is guaranteed to see the freed
bit (winner consumes an earlier bit, which the loser hasn't yet visited).
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Signed-off-by: Peter Gonda <pgonda@google.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006003409.649993-8-seanjc@google.com
Sean Christopherson [Thu, 6 Oct 2022 00:34:08 +0000 (00:34 +0000)]
KVM: selftests: Drop now-unnecessary ucall_uninit()
Drop ucall_uninit() and ucall_arch_uninit() now that ARM doesn't modify
the host's copy of ucall_exit_mmio_addr, i.e. now that there's no need to
reset the pointer before potentially creating a new VM. The few calls to
ucall_uninit() are all immediately followed by kvm_vm_free(), and that is
likely always going to hold true, i.e. it's extremely unlikely a test
will want to effectively disable ucall in the middle of a test.
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Tested-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006003409.649993-7-seanjc@google.com
Sean Christopherson [Thu, 6 Oct 2022 00:34:07 +0000 (00:34 +0000)]
KVM: selftests: Make arm64's MMIO ucall multi-VM friendly
Fix a mostly-theoretical bug where ARM's ucall MMIO setup could result in
different VMs stomping on each other by cloberring the global pointer.
Fix the most obvious issue by saving the MMIO gpa into the VM.
A more subtle bug is that creating VMs in parallel (on multiple tasks)
could result in a VM using the wrong address. Synchronizing a global to
a guest effectively snapshots the value on a per-VM basis, i.e. the
"global" is already prepped to work with multiple VMs, but setting the
global in the host is not thread-safe. To fix that bug, add
write_guest_global() to allow stuffing a VM's copy of a "global" without
modifying the host value.
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Tested-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006003409.649993-6-seanjc@google.com
Peter Gonda [Thu, 6 Oct 2022 00:34:06 +0000 (00:34 +0000)]
tools: Add atomic_test_and_set_bit()
Add x86 and generic implementations of atomic_test_and_set_bit() to allow
KVM selftests to atomically manage bitmaps.
Note, the generic version is taken from arch_test_and_set_bit() as of
commit
415d83249709 ("locking/atomic: Make test_and_*_bit() ordered on
failure").
Signed-off-by: Peter Gonda <pgonda@google.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006003409.649993-5-seanjc@google.com
Sean Christopherson [Thu, 6 Oct 2022 00:34:05 +0000 (00:34 +0000)]
KVM: selftests: Automatically do init_ucall() for non-barebones VMs
Do init_ucall() automatically during VM creation to kill two (three?)
birds with one stone.
First, initializing ucall immediately after VM creations allows forcing
aarch64's MMIO ucall address to immediately follow memslot0. This is
still somewhat fragile as tests could clobber the MMIO address with a
new memslot, but it's safe-ish since tests have to be conversative when
accounting for memslot0. And this can be hardened in the future by
creating a read-only memslot for the MMIO page (KVM ARM exits with MMIO
if the guest writes to a read-only memslot). Add a TODO to document that
selftests can and should use a memslot for the ucall MMIO (doing so
requires yet more rework because tests assumes thay can use all memslots
except memslot0).
Second, initializing ucall for all VMs prepares for making ucall
initialization meaningful on all architectures. aarch64 is currently the
only arch that needs to do any setup, but that will change in the future
by switching to a pool-based implementation (instead of the current
stack-based approach).
Lastly, defining the ucall MMIO address from common code will simplify
switching all architectures (except s390) to a common MMIO-based ucall
implementation (if there's ever sufficient motivation to do so).
Cc: Oliver Upton <oliver.upton@linux.dev>
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Tested-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006003409.649993-4-seanjc@google.com
Sean Christopherson [Thu, 6 Oct 2022 00:34:04 +0000 (00:34 +0000)]
KVM: selftests: Consolidate boilerplate code in get_ucall()
Consolidate the actual copying of a ucall struct from guest=>host into
the common get_ucall(). Return a host virtual address instead of a guest
virtual address even though the addr_gva2hva() part could be moved to
get_ucall() too. Conceptually, get_ucall() is invoked from the host and
should return a host virtual address (and returning NULL for "nothing to
see here" is far superior to returning 0).
Use pointer shenanigans instead of an unnecessary bounce buffer when the
caller of get_ucall() provides a valid pointer.
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Tested-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006003409.649993-3-seanjc@google.com
Sean Christopherson [Thu, 6 Oct 2022 00:34:03 +0000 (00:34 +0000)]
KVM: selftests: Consolidate common code for populating ucall struct
Make ucall() a common helper that populates struct ucall, and only calls
into arch code to make the actually call out to userspace.
Rename all arch-specific helpers to make it clear they're arch-specific,
and to avoid collisions with common helpers (one more on its way...)
Add WRITE_ONCE() to stores in ucall() code (as already done to aarch64
code in commit
9e2f6498efbb ("selftests: KVM: Handle compiler
optimizations in ucall")) to prevent clang optimizations breaking ucalls.
Cc: Colton Lewis <coltonlewis@google.com>
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Tested-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006003409.649993-2-seanjc@google.com
Sean Christopherson [Thu, 17 Nov 2022 00:23:50 +0000 (00:23 +0000)]
KVM: arm64: selftests: Disable single-step without relying on ucall()
Automatically disable single-step when the guest reaches the end of the
verified section instead of using an explicit ucall() to ask userspace to
disable single-step. An upcoming change to implement a pool-based scheme
for ucall() will add an atomic operation (bit test and set) in the guest
ucall code, and if the compiler generate "old school" atomics, e.g.
40e57c:
c85f7c20 ldxr x0, [x1]
40e580:
aa100011 orr x17, x0, x16
40e584:
c80ffc31 stlxr w15, x17, [x1]
40e588:
35ffffaf cbnz w15, 40e57c <__aarch64_ldset8_sync+0x1c>
the guest will hang as the local exclusive monitor is reset by eret,
i.e. the stlxr will always fail due to the debug exception taken to EL2.
Link: https://lore.kernel.org/all/20221006003409.649993-8-seanjc@google.com
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Marc Zyngier <maz@kernel.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221117002350.2178351-3-seanjc@google.com
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Sean Christopherson [Thu, 17 Nov 2022 00:23:49 +0000 (00:23 +0000)]
KVM: arm64: selftests: Disable single-step with correct KVM define
Disable single-step by setting debug.control to KVM_GUESTDBG_ENABLE,
not to SINGLE_STEP_DISABLE. The latter is an arbitrary test enum that
just happens to have the same value as KVM_GUESTDBG_ENABLE, and so
effectively disables single-step debug.
No functional change intended.
Cc: Reiji Watanabe <reijiw@google.com>
Fixes:
b18e4d4aebdd ("KVM: arm64: selftests: Add a test case for KVM_GUESTDBG_SINGLESTEP")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221117002350.2178351-2-seanjc@google.com
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
David Matlack [Wed, 12 Oct 2022 16:57:29 +0000 (09:57 -0700)]
KVM: selftests: Rename perf_test_util symbols to memstress
Replace the perf_test_ prefix on symbol names with memstress_ to match
the new file name.
"memstress" better describes the functionality proveded by this library,
which is to provide functionality for creating and running a VM that
stresses VM memory by reading and writing to guest memory on all vCPUs
in parallel.
"memstress" also contains the same number of chracters as "perf_test",
making it a drop-in replacement in symbols, e.g. function names, without
impacting line lengths. Also the lack of underscore between "mem" and
"stress" makes it clear "memstress" is a noun.
Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221012165729.3505266-4-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
David Matlack [Wed, 12 Oct 2022 16:57:28 +0000 (09:57 -0700)]
KVM: selftests: Rename pta (short for perf_test_args) to args
Rename the local variables "pta" (which is short for perf_test_args) for
args. "pta" is not an obvious acronym and using "args" mirrors
"vcpu_args".
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221012165729.3505266-3-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
David Matlack [Wed, 12 Oct 2022 16:57:27 +0000 (09:57 -0700)]
KVM: selftests: Rename perf_test_util.[ch] to memstress.[ch]
Rename the perf_test_util.[ch] files to memstress.[ch]. Symbols are
renamed in the following commit to reduce the amount of churn here in
hopes of playiing nice with git's file rename detection.
The name "memstress" was chosen to better describe the functionality
proveded by this library, which is to create and run a VM that
reads/writes to guest memory on all vCPUs in parallel.
"memstress" also contains the same number of chracters as "perf_test",
making it a drop-in replacement in symbols, e.g. function names, without
impacting line lengths. Also the lack of underscore between "mem" and
"stress" makes it clear "memstress" is a noun.
Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221012165729.3505266-2-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Colton Lewis [Mon, 7 Nov 2022 18:22:08 +0000 (18:22 +0000)]
KVM: selftests: randomize page access order
Create the ability to randomize page access order with the -a
argument. This includes the possibility that the same pages may be hit
multiple times during an iteration or not at all.
Population has random access as false to ensure all pages will be
touched by population and avoid page faults in late dirty memory that
would pollute the test results.
Signed-off-by: Colton Lewis <coltonlewis@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20221107182208.479157-5-coltonlewis@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Colton Lewis [Mon, 7 Nov 2022 18:22:07 +0000 (18:22 +0000)]
KVM: selftests: randomize which pages are written vs read
Randomize which pages are written vs read using the random number
generator.
Change the variable wr_fract and associated function calls to
write_percent that now operates as a percentage from 0 to 100 where X
means each page has an X% chance of being written. Change the -f
argument to -w to reflect the new variable semantics. Keep the same
default of 100% writes.
Population always uses 100% writes to ensure all memory is actually
populated and not just mapped to the zero page. The prevents expensive
copy-on-write faults from occurring during the dirty memory iterations
below, which would pollute the performance results.
Each vCPU calculates its own random seed by adding its index to the
seed provided.
Signed-off-by: Colton Lewis <coltonlewis@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20221107182208.479157-4-coltonlewis@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Colton Lewis [Mon, 7 Nov 2022 18:22:06 +0000 (18:22 +0000)]
KVM: selftests: create -r argument to specify random seed
Create a -r argument to specify a random seed. If no argument is
provided, the seed defaults to 1. The random seed is set with
perf_test_set_random_seed() and must be set before guest_code runs to
apply.
Signed-off-by: Colton Lewis <coltonlewis@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20221107182208.479157-3-coltonlewis@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Colton Lewis [Mon, 7 Nov 2022 18:22:05 +0000 (18:22 +0000)]
KVM: selftests: implement random number generator for guest code
Implement random number generator for guest code to randomize parts
of the test, making it less predictable and a more accurate reflection
of reality.
The random number generator chosen is the Park-Miller Linear
Congruential Generator, a fancy name for a basic and well-understood
random number generator entirely sufficient for this purpose.
Signed-off-by: Colton Lewis <coltonlewis@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20221107182208.479157-2-coltonlewis@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Vipin Sharma [Thu, 3 Nov 2022 19:17:19 +0000 (12:17 -0700)]
KVM: selftests: Allowing running dirty_log_perf_test on specific CPUs
Add a command line option, -c, to pin vCPUs to physical CPUs (pCPUs),
i.e. to force vCPUs to run on specific pCPUs.
Requirement to implement this feature came in discussion on the patch
"Make page tables for eager page splitting NUMA aware"
https://lore.kernel.org/lkml/YuhPT2drgqL+osLl@google.com/
This feature is useful as it provides a way to analyze performance based
on the vCPUs and dirty log worker locations, like on the different NUMA
nodes or on the same NUMA nodes.
To keep things simple, implementation is intentionally very limited,
either all of the vCPUs will be pinned followed by an optional main
thread or nothing will be pinned.
Signed-off-by: Vipin Sharma <vipinsh@google.com>
Suggested-by: David Matlack <dmatlack@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221103191719.1559407-8-vipinsh@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Vipin Sharma [Thu, 3 Nov 2022 19:17:18 +0000 (12:17 -0700)]
KVM: selftests: Add atoi_positive() and atoi_non_negative() for input validation
Many KVM selftests take command line arguments which are supposed to be
positive (>0) or non-negative (>=0). Some tests do these validation and
some missed adding the check.
Add atoi_positive() and atoi_non_negative() to validate inputs in
selftests before proceeding to use those values.
Signed-off-by: Vipin Sharma <vipinsh@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221103191719.1559407-7-vipinsh@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Vipin Sharma [Thu, 3 Nov 2022 19:17:17 +0000 (12:17 -0700)]
KVM: selftests: Shorten the test args in memslot_modification_stress_test.c
Change test args memslot_modification_delay and nr_memslot_modifications
to delay and nr_iterations for simplicity.
Signed-off-by: Vipin Sharma <vipinsh@google.com>
Suggested-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221103191719.1559407-6-vipinsh@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Vipin Sharma [Thu, 3 Nov 2022 19:17:16 +0000 (12:17 -0700)]
KVM: selftests: Use SZ_* macros from sizes.h in max_guest_memory_test.c
Replace size_1gb defined in max_guest_memory_test.c with the SZ_1G,
SZ_2G and SZ_4G from linux/sizes.h header file.
Signed-off-by: Vipin Sharma <vipinsh@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221103191719.1559407-5-vipinsh@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Vipin Sharma [Thu, 3 Nov 2022 19:17:15 +0000 (12:17 -0700)]
KVM: selftests: Add atoi_paranoid() to catch errors missed by atoi()
atoi() doesn't detect errors. There is no way to know that a 0 return
is correct conversion or due to an error.
Introduce atoi_paranoid() to detect errors and provide correct
conversion. Replace all atoi() calls with atoi_paranoid().
Signed-off-by: Vipin Sharma <vipinsh@google.com>
Suggested-by: David Matlack <dmatlack@google.com>
Suggested-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221103191719.1559407-4-vipinsh@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Vipin Sharma [Thu, 3 Nov 2022 19:17:14 +0000 (12:17 -0700)]
KVM: selftests: Put command line options in alphabetical order in dirty_log_perf_test
There are 13 command line options and they are not in any order. Put
them in alphabetical order to make it easy to add new options.
No functional change intended.
Signed-off-by: Vipin Sharma <vipinsh@google.com>
Reviewed-by: Wei Wang <wei.w.wang@intel.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221103191719.1559407-3-vipinsh@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Vipin Sharma [Thu, 3 Nov 2022 19:17:13 +0000 (12:17 -0700)]
KVM: selftests: Add missing break between -e and -g option in dirty_log_perf_test
Passing -e option (Run VCPUs while dirty logging is being disabled) in
dirty_log_perf_test also unintentionally enables -g (Do not enable
KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2). Add break between two switch case
logic.
Fixes:
cfe12e64b065 ("KVM: selftests: Add an option to run vCPUs while disabling dirty logging")
Signed-off-by: Vipin Sharma <vipinsh@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221103191719.1559407-2-vipinsh@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Paolo Bonzini [Thu, 3 Nov 2022 14:44:10 +0000 (10:44 -0400)]
KVM: replace direct irq.h inclusion
virt/kvm/irqchip.c is including "irq.h" from the arch-specific KVM source
directory (i.e. not from arch/*/include) for the sole purpose of retrieving
irqchip_in_kernel.
Making the function inline in a header that is already included,
such as asm/kvm_host.h, is not possible because it needs to look at
struct kvm which is defined after asm/kvm_host.h is included. So add a
kvm_arch_irqchip_in_kernel non-inline function; irqchip_in_kernel() is
only performance critical on arm64 and x86, and the non-inline function
is enough on all other architectures.
irq.h can then be deleted from all architectures except x86.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Like Xu [Fri, 23 Sep 2022 00:13:55 +0000 (00:13 +0000)]
KVM: x86/pmu: Defer counter emulated overflow via pmc->prev_counter
Defer reprogramming counters and handling overflow via KVM_REQ_PMU
when incrementing counters. KVM skips emulated WRMSR in the VM-Exit
fastpath, the fastpath runs with IRQs disabled, skipping instructions
can increment and reprogram counters, reprogramming counters can
sleep, and sleeping is disallowed while IRQs are disabled.
[*] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:580
[*] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid:
2981888, name: CPU 15/KVM
[*] preempt_count: 1, expected: 0
[*] RCU nest depth: 0, expected: 0
[*] INFO: lockdep is turned off.
[*] irq event stamp: 0
[*] hardirqs last enabled at (0): [<
0000000000000000>] 0x0
[*] hardirqs last disabled at (0): [<
ffffffff8121222a>] copy_process+0x146a/0x62d0
[*] softirqs last enabled at (0): [<
ffffffff81212269>] copy_process+0x14a9/0x62d0
[*] softirqs last disabled at (0): [<
0000000000000000>] 0x0
[*] Preemption disabled at:
[*] [<
ffffffffc2063fc1>] vcpu_enter_guest+0x1001/0x3dc0 [kvm]
[*] CPU: 17 PID:
2981888 Comm: CPU 15/KVM Kdump:
5.19.0-rc1-g239111db364c-dirty #2
[*] Call Trace:
[*] <TASK>
[*] dump_stack_lvl+0x6c/0x9b
[*] __might_resched.cold+0x22e/0x297
[*] __mutex_lock+0xc0/0x23b0
[*] perf_event_ctx_lock_nested+0x18f/0x340
[*] perf_event_pause+0x1a/0x110
[*] reprogram_counter+0x2af/0x1490 [kvm]
[*] kvm_pmu_trigger_event+0x429/0x950 [kvm]
[*] kvm_skip_emulated_instruction+0x48/0x90 [kvm]
[*] handle_fastpath_set_msr_irqoff+0x349/0x3b0 [kvm]
[*] vmx_vcpu_run+0x268e/0x3b80 [kvm_intel]
[*] vcpu_enter_guest+0x1d22/0x3dc0 [kvm]
Add a field to kvm_pmc to track the previous counter value in order
to defer overflow detection to kvm_pmu_handle_event() (the counter must
be paused before handling overflow, and that may increment the counter).
Opportunistically shrink sizeof(struct kvm_pmc) a bit.
Suggested-by: Wanpeng Li <wanpengli@tencent.com>
Fixes:
9cd803d496e7 ("KVM: x86: Update vPMCs when retiring instructions")
Signed-off-by: Like Xu <likexu@tencent.com>
Link: https://lore.kernel.org/r/20220831085328.45489-6-likexu@tencent.com
[sean: avoid re-triggering KVM_REQ_PMU on overflow, tweak changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <
20220923001355.
3741194-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Like Xu [Fri, 23 Sep 2022 00:13:54 +0000 (00:13 +0000)]
KVM: x86/pmu: Defer reprogram_counter() to kvm_pmu_handle_event()
Batch reprogramming PMU counters by setting KVM_REQ_PMU and thus
deferring reprogramming kvm_pmu_handle_event() to avoid reprogramming
a counter multiple times during a single VM-Exit.
Deferring programming will also allow KVM to fix a bug where immediately
reprogramming a counter can result in sleeping (taking a mutex) while
interrupts are disabled in the VM-Exit fastpath.
Introduce kvm_pmu_request_counter_reprogam() to make it obvious that
KVM is _requesting_ a reprogram and not actually doing the reprogram.
Opportunistically refine related comments to avoid misunderstandings.
Signed-off-by: Like Xu <likexu@tencent.com>
Link: https://lore.kernel.org/r/20220831085328.45489-5-likexu@tencent.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <
20220923001355.
3741194-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 23 Sep 2022 00:13:53 +0000 (00:13 +0000)]
KVM: x86/pmu: Clear "reprogram" bit if counter is disabled or disallowed
When reprogramming a counter, clear the counter's "reprogram pending" bit
if the counter is disabled (by the guest) or is disallowed (by the
userspace filter). In both cases, there's no need to re-attempt
programming on the next coincident KVM_REQ_PMU as enabling the counter by
either method will trigger reprogramming.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <
20220923001355.
3741194-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 23 Sep 2022 00:13:52 +0000 (00:13 +0000)]
KVM: x86/pmu: Force reprogramming of all counters on PMU filter change
Force vCPUs to reprogram all counters on a PMU filter change to provide
a sane ABI for userspace. Use the existing KVM_REQ_PMU to do the
programming, and take advantage of the fact that the reprogram_pmi bitmap
fits in a u64 to set all bits in a single atomic update. Note, setting
the bitmap and making the request needs to be done _after_ the SRCU
synchronization to ensure that vCPUs will reprogram using the new filter.
KVM's current "lazy" approach is confusing and non-deterministic. It's
confusing because, from a developer perspective, the code is buggy as it
makes zero sense to let userspace modify the filter but then not actually
enforce the new filter. The lazy approach is non-deterministic because
KVM enforces the filter whenever a counter is reprogrammed, not just on
guest WRMSRs, i.e. a guest might gain/lose access to an event at random
times depending on what is going on in the host.
Note, the resulting behavior is still non-determinstic while the filter
is in flux. If userspace wants to guarantee deterministic behavior, all
vCPUs should be paused during the filter update.
Jim Mattson <jmattson@google.com>
Fixes:
66bb8a065f5a ("KVM: x86: PMU Event Filter")
Cc: Aaron Lewis <aaronlewis@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <
20220923001355.
3741194-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Wed, 19 Oct 2022 16:56:18 +0000 (16:56 +0000)]
KVM: x86/mmu: WARN if TDP MMU SP disallows hugepage after being zapped
Extend the accounting sanity check in kvm_recover_nx_huge_pages() to the
TDP MMU, i.e. verify that zapping a shadow page unaccounts the disallowed
NX huge page regardless of the MMU type. Recovery runs while holding
mmu_lock for write and so it should be impossible to get false positives
on the WARN.
Suggested-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <
20221019165618.927057-9-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Mingwei Zhang [Wed, 19 Oct 2022 16:56:17 +0000 (16:56 +0000)]
KVM: x86/mmu: explicitly check nx_hugepage in disallowed_hugepage_adjust()
Explicitly check if a NX huge page is disallowed when determining if a
page fault needs to be forced to use a smaller sized page. KVM currently
assumes that the NX huge page mitigation is the only scenario where KVM
will force a shadow page instead of a huge page, and so unnecessarily
keeps an existing shadow page instead of replacing it with a huge page.
Any scenario that causes KVM to zap leaf SPTEs may result in having a SP
that can be made huge without violating the NX huge page mitigation.
E.g. prior to commit
5ba7c4c6d1c7 ("KVM: x86/MMU: Zap non-leaf SPTEs when
disabling dirty logging"), KVM would keep shadow pages after disabling
dirty logging due to a live migration being canceled, resulting in
degraded performance due to running with 4kb pages instead of huge pages.
Although the dirty logging case is "fixed", that fix is coincidental,
i.e. is an implementation detail, and there are other scenarios where KVM
will zap leaf SPTEs. E.g. zapping leaf SPTEs in response to a host page
migration (mmu_notifier invalidation) to create a huge page would yield a
similar result; KVM would see the shadow-present non-leaf SPTE and assume
a huge page is disallowed.
Fixes:
b8e8c8303ff2 ("kvm: mmu: ITLB_MULTIHIT mitigation")
Reviewed-by: Ben Gardon <bgardon@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
[sean: use spte_to_child_sp(), massage changelog, fold into if-statement]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Message-Id: <
20221019165618.927057-8-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Wed, 19 Oct 2022 16:56:16 +0000 (16:56 +0000)]
KVM: x86/mmu: Add helper to convert SPTE value to its shadow page
Add a helper to convert a SPTE to its shadow page to deduplicate a
variety of flows and hopefully avoid future bugs, e.g. if KVM attempts to
get the shadow page for a SPTE without dropping high bits.
Opportunistically add a comment in mmu_free_root_page() documenting why
it treats the root HPA as a SPTE.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <
20221019165618.927057-7-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Wed, 19 Oct 2022 16:56:15 +0000 (16:56 +0000)]
KVM: x86/mmu: Track the number of TDP MMU pages, but not the actual pages
Track the number of TDP MMU "shadow" pages instead of tracking the pages
themselves. With the NX huge page list manipulation moved out of the common
linking flow, elminating the list-based tracking means the happy path of
adding a shadow page doesn't need to acquire a spinlock and can instead
inc/dec an atomic.
Keep the tracking as the WARN during TDP MMU teardown on leaked shadow
pages is very, very useful for detecting KVM bugs.
Tracking the number of pages will also make it trivial to expose the
counter to userspace as a stat in the future, which may or may not be
desirable.
Note, the TDP MMU needs to use a separate counter (and stat if that ever
comes to be) from the existing n_used_mmu_pages. The TDP MMU doesn't bother
supporting the shrinker nor does it honor KVM_SET_NR_MMU_PAGES (because the
TDP MMU consumes so few pages relative to shadow paging), and including TDP
MMU pages in that counter would break both the shrinker and shadow MMUs,
e.g. if a VM is using nested TDP.
Cc: Yan Zhao <yan.y.zhao@intel.com>
Reviewed-by: Mingwei Zhang <mizhang@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Message-Id: <
20221019165618.927057-6-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Wed, 19 Oct 2022 16:56:14 +0000 (16:56 +0000)]
KVM: x86/mmu: Set disallowed_nx_huge_page in TDP MMU before setting SPTE
Set nx_huge_page_disallowed in TDP MMU shadow pages before making the SP
visible to other readers, i.e. before setting its SPTE. This will allow
KVM to query the flag when determining if a shadow page can be replaced
by a NX huge page without violating the rules of the mitigation.
Note, the shadow/legacy MMU holds mmu_lock for write, so it's impossible
for another CPU to see a shadow page without an up-to-date
nx_huge_page_disallowed, i.e. only the TDP MMU needs the complicated
dance.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Message-Id: <
20221019165618.927057-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Wed, 19 Oct 2022 16:56:13 +0000 (16:56 +0000)]
KVM: x86/mmu: Properly account NX huge page workaround for nonpaging MMUs
Account and track NX huge pages for nonpaging MMUs so that a future
enhancement to precisely check if a shadow page can't be replaced by a NX
huge page doesn't get false positives. Without correct tracking, KVM can
get stuck in a loop if an instruction is fetching and writing data on the
same huge page, e.g. KVM installs a small executable page on the fetch
fault, replaces it with an NX huge page on the write fault, and faults
again on the fetch.
Alternatively, and perhaps ideally, KVM would simply not enforce the
workaround for nonpaging MMUs. The guest has no page tables to abuse
and KVM is guaranteed to switch to a different MMU on CR0.PG being
toggled so there's no security or performance concerns. However, getting
make_spte() to play nice now and in the future is unnecessarily complex.
In the current code base, make_spte() can enforce the mitigation if TDP
is enabled or the MMU is indirect, but make_spte() may not always have a
vCPU/MMU to work with, e.g. if KVM were to support in-line huge page
promotion when disabling dirty logging.
Without a vCPU/MMU, KVM could either pass in the correct information
and/or derive it from the shadow page, but the former is ugly and the
latter subtly non-trivial due to the possibility of direct shadow pages
in indirect MMUs. Given that using shadow paging with an unpaged guest
is far from top priority _and_ has been subjected to the workaround since
its inception, keep it simple and just fix the accounting glitch.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Mingwei Zhang <mizhang@google.com>
Message-Id: <
20221019165618.927057-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Wed, 19 Oct 2022 16:56:12 +0000 (16:56 +0000)]
KVM: x86/mmu: Rename NX huge pages fields/functions for consistency
Rename most of the variables/functions involved in the NX huge page
mitigation to provide consistency, e.g. lpage vs huge page, and NX huge
vs huge NX, and also to provide clarity, e.g. to make it obvious the flag
applies only to the NX huge page mitigation, not to any condition that
prevents creating a huge page.
Add a comment explaining what the newly named "possible_nx_huge_pages"
tracks.
Leave the nx_lpage_splits stat alone as the name is ABI and thus set in
stone.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Mingwei Zhang <mizhang@google.com>
Message-Id: <
20221019165618.927057-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Wed, 19 Oct 2022 16:56:11 +0000 (16:56 +0000)]
KVM: x86/mmu: Tag disallowed NX huge pages even if they're not tracked
Tag shadow pages that cannot be replaced with an NX huge page regardless
of whether or not zapping the page would allow KVM to immediately create
a huge page, e.g. because something else prevents creating a huge page.
I.e. track pages that are disallowed from being NX huge pages regardless
of whether or not the page could have been huge at the time of fault.
KVM currently tracks pages that were disallowed from being huge due to
the NX workaround if and only if the page could otherwise be huge. But
that fails to handled the scenario where whatever restriction prevented
KVM from installing a huge page goes away, e.g. if dirty logging is
disabled, the host mapping level changes, etc...
Failure to tag shadow pages appropriately could theoretically lead to
false negatives, e.g. if a fetch fault requests a small page and thus
isn't tracked, and a read/write fault later requests a huge page, KVM
will not reject the huge page as it should.
To avoid yet another flag, initialize the list_head and use list_empty()
to determine whether or not a page is on the list of NX huge pages that
should be recovered.
Note, the TDP MMU accounting is still flawed as fixing the TDP MMU is
more involved due to mmu_lock being held for read. This will be
addressed in a future commit.
Fixes:
5bcaf3e1715f ("KVM: x86/mmu: Account NX huge page disallowed iff huge page was requested")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <
20221019165618.927057-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Aaron Lewis [Wed, 21 Sep 2022 15:15:25 +0000 (15:15 +0000)]
selftests: kvm/x86: Test the flags in MSR filtering and MSR exiting
When using the flags in KVM_X86_SET_MSR_FILTER and
KVM_CAP_X86_USER_SPACE_MSR it is expected that an attempt to write to
any of the unused bits will fail. Add testing to walk over every bit
in each of the flag fields in MSR filtering and MSR exiting to verify
that unused bits return and error and used bits, i.e. valid bits,
succeed.
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Message-Id: <
20220921151525.904162-6-aaronlewis@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Aaron Lewis [Wed, 21 Sep 2022 15:15:24 +0000 (15:15 +0000)]
KVM: x86: Add a VALID_MASK for the flags in kvm_msr_filter_range
Add the mask KVM_MSR_FILTER_RANGE_VALID_MASK for the flags in the
struct kvm_msr_filter_range. This simplifies checks that validate
these flags, and makes it easier to introduce new flags in the future.
No functional change intended.
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Message-Id: <
20220921151525.904162-5-aaronlewis@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Aaron Lewis [Wed, 21 Sep 2022 15:15:23 +0000 (15:15 +0000)]
KVM: x86: Add a VALID_MASK for the flag in kvm_msr_filter
Add the mask KVM_MSR_FILTER_VALID_MASK for the flag in the struct
kvm_msr_filter. This makes it easier to introduce new flags in the
future.
No functional change intended.
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Message-Id: <
20220921151525.904162-4-aaronlewis@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Aaron Lewis [Wed, 21 Sep 2022 15:15:22 +0000 (15:15 +0000)]
KVM: x86: Add a VALID_MASK for the MSR exit reason flags
Add the mask KVM_MSR_EXIT_REASON_VALID_MASK for the MSR exit reason
flags. This simplifies checks that validate these flags, and makes it
easier to introduce new flags in the future.
No functional change intended.
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Message-Id: <
20220921151525.904162-3-aaronlewis@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Aaron Lewis [Wed, 21 Sep 2022 15:15:21 +0000 (15:15 +0000)]
KVM: x86: Disallow the use of KVM_MSR_FILTER_DEFAULT_ALLOW in the kernel
Protect the kernel from using the flag KVM_MSR_FILTER_DEFAULT_ALLOW.
Its value is 0, and using it incorrectly could have unintended
consequences. E.g. prevent someone in the kernel from writing something
like this.
if (filter.flags & KVM_MSR_FILTER_DEFAULT_ALLOW)
<allow the MSR>
and getting confused when it doesn't work.
It would be more ideal to remove this flag altogether, but userspace
may already be using it, so protecting the kernel is all that can
reasonably be done at this point.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <
20220921151525.904162-2-aaronlewis@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Peter Xu [Tue, 11 Oct 2022 19:59:47 +0000 (15:59 -0400)]
kvm: x86: Allow to respond to generic signals during slow PF
Enable x86 slow page faults to be able to respond to non-fatal signals,
returning -EINTR properly when it happens.
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <
20221011195947.557281-1-peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Peter Xu [Tue, 11 Oct 2022 19:58:08 +0000 (15:58 -0400)]
kvm: Add interruptible flag to __gfn_to_pfn_memslot()
Add a new "interruptible" flag showing that the caller is willing to be
interrupted by signals during the __gfn_to_pfn_memslot() request. Wire it
up with a FOLL_INTERRUPTIBLE flag that we've just introduced.
This prepares KVM to be able to respond to SIGUSR1 (for QEMU that's the
SIGIPI) even during e.g. handling an userfaultfd page fault.
No functional change intended.
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <
20221011195809.557016-4-peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Peter Xu [Tue, 11 Oct 2022 19:58:07 +0000 (15:58 -0400)]
kvm: Add KVM_PFN_ERR_SIGPENDING
Add a new pfn error to show that we've got a pending signal to handle
during hva_to_pfn_slow() procedure (of -EINTR retval).
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <
20221011195809.557016-3-peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Peter Xu [Tue, 11 Oct 2022 19:58:06 +0000 (15:58 -0400)]
mm/gup: Add FOLL_INTERRUPTIBLE
We have had FAULT_FLAG_INTERRUPTIBLE but it was never applied to GUPs. One
issue with it is that not all GUP paths are able to handle signal delivers
besides SIGKILL.
That's not ideal for the GUP users who are actually able to handle these
cases, like KVM.
KVM uses GUP extensively on faulting guest pages, during which we've got
existing infrastructures to retry a page fault at a later time. Allowing
the GUP to be interrupted by generic signals can make KVM related threads
to be more responsive. For examples:
(1) SIGUSR1: which QEMU/KVM uses to deliver an inter-process IPI,
e.g. when the admin issues a vm_stop QMP command, SIGUSR1 can be
generated to kick the vcpus out of kernel context immediately,
(2) SIGINT: which can be used with interactive hypervisor users to stop a
virtual machine with Ctrl-C without any delays/hangs,
(3) SIGTRAP: which grants GDB capability even during page faults that are
stuck for a long time.
Normally hypervisor will be able to receive these signals properly, but not
if we're stuck in a GUP for a long time for whatever reason. It happens
easily with a stucked postcopy migration when e.g. a network temp failure
happens, then some vcpu threads can hang death waiting for the pages. With
the new FOLL_INTERRUPTIBLE, we can allow GUP users like KVM to selectively
enable the ability to trap these signals.
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <
20221011195809.557016-2-peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Maxim Levitsky [Tue, 25 Oct 2022 12:47:41 +0000 (15:47 +0300)]
KVM: x86: smm: preserve interrupt shadow in SMRAM
When #SMI is asserted, the CPU can be in interrupt shadow due to sti or
mov ss.
It is not mandatory in Intel/AMD prm to have the #SMI blocked during the
shadow, and on top of that, since neither SVM nor VMX has true support
for SMI window, waiting for one instruction would mean single stepping
the guest.
Instead, allow #SMI in this case, but both reset the interrupt window and
stash its value in SMRAM to restore it on exit from SMM.
This fixes rare failures seen mostly on windows guests on VMX, when #SMI
falls on the sti instruction which mainfest in VM entry failure due
to EFLAGS.IF not being set, but STI interrupt window still being set
in the VMCS.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <
20221025124741.228045-24-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Maxim Levitsky [Tue, 25 Oct 2022 12:47:40 +0000 (15:47 +0300)]
KVM: x86: SVM: don't save SVM state to SMRAM when VM is not long mode capable
When the guest CPUID doesn't have support for long mode, 32 bit SMRAM
layout is used and it has no support for preserving EFER and/or SVM
state.
Note that this isn't relevant to running 32 bit guests on VM which is
long mode capable - such VM can still run 32 bit guests in compatibility
mode.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <
20221025124741.228045-23-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Maxim Levitsky [Tue, 25 Oct 2022 12:47:39 +0000 (15:47 +0300)]
KVM: x86: SVM: use smram structs
Use SMM structs in the SVM code as well, which removes the last user of
put_smstate/GET_SMSTATE so remove these macros as well.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <
20221025124741.228045-22-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Maxim Levitsky [Tue, 25 Oct 2022 12:47:38 +0000 (15:47 +0300)]
KVM: svm: drop explicit return value of kvm_vcpu_map
if kvm_vcpu_map returns non zero value, error path should be triggered
regardless of the exact returned error value.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <
20221025124741.228045-21-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Maxim Levitsky [Tue, 25 Oct 2022 12:47:37 +0000 (15:47 +0300)]
KVM: x86: smm: use smram struct for 64 bit smram load/restore
Use kvm_smram_state_64 struct to save/restore the 64 bit SMM state
(used when X86_FEATURE_LM is present in the guest CPUID,
regardless of 32-bitness of the guest).
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <
20221025124741.228045-20-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Maxim Levitsky [Tue, 25 Oct 2022 12:47:36 +0000 (15:47 +0300)]
KVM: x86: smm: use smram struct for 32 bit smram load/restore
Use kvm_smram_state_32 struct to save/restore 32 bit SMM state
(used when X86_FEATURE_LM is not present in the guest CPUID).
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <
20221025124741.228045-19-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Maxim Levitsky [Tue, 25 Oct 2022 12:47:35 +0000 (15:47 +0300)]
KVM: x86: smm: use smram structs in the common code
Use kvm_smram union instad of raw arrays in the common smm code.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <
20221025124741.228045-18-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Maxim Levitsky [Tue, 25 Oct 2022 12:47:34 +0000 (15:47 +0300)]
KVM: x86: smm: add structs for KVM's smram layout
Add structs that will be used to define and read/write the KVM's
SMRAM layout, instead of reading/writing to raw offsets.
Also document the differences between KVM's SMRAM layout and SMRAM
layout that is used by real Intel/AMD cpus.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <
20221025124741.228045-17-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Maxim Levitsky [Tue, 25 Oct 2022 12:47:33 +0000 (15:47 +0300)]
KVM: x86: smm: check for failures on smm entry
In the rare case of the failure on SMM entry, the KVM should at
least terminate the VM instead of going south.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <
20221025124741.228045-16-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Mon, 7 Nov 2022 15:11:42 +0000 (10:11 -0500)]
KVM: x86: do not define SMM-related constants if SMM disabled
The hidden processor flags HF_SMM_MASK and HF_SMM_INSIDE_NMI_MASK
are not needed if CONFIG_KVM_SMM is turned off. Remove the
definitions altogether and the code that uses them.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Thu, 27 Oct 2022 16:44:28 +0000 (12:44 -0400)]
KVM: zero output of KVM_GET_VCPU_EVENTS before filling in the struct
This allows making some fields optional, as will be the case soon
for SMM-related data.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Thu, 29 Sep 2022 17:20:16 +0000 (13:20 -0400)]
KVM: x86: do not define KVM_REQ_SMI if SMM disabled
This ensures that all the relevant code is compiled out, in fact
the process_smi stub can be removed too.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <
20220929172016.319443-9-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Thu, 29 Sep 2022 17:20:15 +0000 (13:20 -0400)]
KVM: x86: remove SMRAM address space if SMM is not supported
If CONFIG_KVM_SMM is not defined HF_SMM_MASK will always be zero, and
we can spare userspace the hassle of setting up the SMRAM address space
simply by reporting that only one address space is supported.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <
20220929172016.319443-8-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Thu, 29 Sep 2022 17:20:14 +0000 (13:20 -0400)]
KVM: x86: compile out vendor-specific code if SMM is disabled
Vendor-specific code that deals with SMI injection and saving/restoring
SMM state is not needed if CONFIG_KVM_SMM is disabled, so remove the
four callbacks smi_allowed, enter_smm, leave_smm and enable_smi_window.
The users in svm/nested.c and x86.c also have to be compiled out; the
amount of #ifdef'ed code is small and it's not worth moving it to
smm.c.
enter_smm is now used only within #ifdef CONFIG_KVM_SMM, and the stub
can therefore be removed.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <
20220929172016.319443-7-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Thu, 29 Sep 2022 17:20:13 +0000 (13:20 -0400)]
KVM: allow compiling out SMM support
Some users of KVM implement the UEFI variable store through a paravirtual device
that does not require the "SMM lockbox" component of edk2; allow them to
compile out system management mode, which is not a full implementation
especially in how it interacts with nested virtualization.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <
20220929172016.319443-6-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Thu, 29 Sep 2022 17:20:12 +0000 (13:20 -0400)]
KVM: x86: do not go through ctxt->ops when emulating rsm
Now that RSM is implemented in a single emulator callback, there is no
point in going through other callbacks for the sake of modifying
processor state. Just invoke KVM's own internal functions directly,
and remove the callbacks that were only used by em_rsm; the only
substantial difference is in the handling of the segment registers
and descriptor cache, which have to be parsed into a struct kvm_segment
instead of a struct desc_struct.
This also fixes a bug where emulator_set_segment was shifting the
limit left by 12 if the G bit is set, but the limit had not been
shifted right upon entry to SMM.
The emulator context is still used to restore EIP and the general
purpose registers.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <
20220929172016.319443-5-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Fri, 28 Oct 2022 10:01:26 +0000 (06:01 -0400)]
KVM: x86: move SMM exit to a new file
Some users of KVM implement the UEFI variable store through a paravirtual
device that does not require the "SMM lockbox" component of edk2, and
would like to compile out system management mode. In preparation for
that, move the SMM exit code out of emulate.c and into a new file.
The code is still written as a series of invocations of the emulator
callbacks, but the two exiting_smm and leave_smm callbacks are merged
into one, and all the code from em_rsm is now part of the callback.
This removes all knowledge of the format of the SMM save state area
from the emulator. Further patches will clean up the code and
invoke KVM's own functions to access control registers, descriptor
caches, etc.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <
20220929172016.319443-4-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Thu, 29 Sep 2022 17:20:10 +0000 (13:20 -0400)]
KVM: x86: move SMM entry to a new file
Some users of KVM implement the UEFI variable store through a paravirtual
device that does not require the "SMM lockbox" component of edk2, and
would like to compile out system management mode. In preparation for
that, move the SMM entry code out of x86.c and into a new file.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <
20220929172016.319443-3-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Thu, 29 Sep 2022 17:20:09 +0000 (13:20 -0400)]
KVM: x86: start moving SMM-related functions to new files
Create a new header and source with code related to system management
mode emulation. Entry and exit will move there too; for now,
opportunistically rename put_smstate to PUT_SMSTATE while moving
it to smm.h, and adjust the SMM state saving code.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <
20220929172016.319443-2-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Carlos Bilbao [Mon, 24 Oct 2022 16:44:48 +0000 (11:44 -0500)]
KVM: SVM: Name and check reserved fields with structs offset
Rename reserved fields on all structs in arch/x86/include/asm/svm.h
following their offset within the structs. Include compile time checks for
this in the same place where other BUILD_BUG_ON for the structs are.
This also solves that fields of struct sev_es_save_area are named by their
order of appearance, but right now they jump from reserved_5 to reserved_7.
Link: https://lkml.org/lkml/2022/10/22/376
Signed-off-by: Carlos Bilbao <carlos.bilbao@amd.com>
Message-Id: <
20221024164448.203351-1-carlos.bilbao@amd.com>
[Use ASSERT_STRUCT_OFFSET + fix a couple wrong offsets. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>