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KVM: arm64: Duplicate hyp/tlb.c for VHE/nVHE
authorDavid Brazdil <dbrazdil@google.com>
Thu, 25 Jun 2020 13:14:13 +0000 (14:14 +0100)
committerMarc Zyngier <maz@kernel.org>
Sun, 5 Jul 2020 17:38:17 +0000 (18:38 +0100)
tlb.c contains code for flushing the TLB, with code shared between VHE/nVHE.
Because common code is small, duplicate tlb.c and specialize each copy for
VHE/nVHE.

Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200625131420.71444-9-dbrazdil@google.com
arch/arm64/kernel/image-vars.h
arch/arm64/kvm/hyp/Makefile
arch/arm64/kvm/hyp/nvhe/Makefile
arch/arm64/kvm/hyp/nvhe/tlb.c [moved from arch/arm64/kvm/hyp/tlb.c with 61% similarity]
arch/arm64/kvm/hyp/vhe/Makefile
arch/arm64/kvm/hyp/vhe/tlb.c [new file with mode: 0644]

index 63186c9..f029f3e 100644 (file)
@@ -81,12 +81,6 @@ KVM_NVHE_ALIAS(__kvm_enable_ssbs);
 /* Symbols defined in timer-sr.c (not yet compiled with nVHE build rules). */
 KVM_NVHE_ALIAS(__kvm_timer_set_cntvoff);
 
-/* Symbols defined in tlb.c (not yet compiled with nVHE build rules). */
-KVM_NVHE_ALIAS(__kvm_flush_vm_context);
-KVM_NVHE_ALIAS(__kvm_tlb_flush_local_vmid);
-KVM_NVHE_ALIAS(__kvm_tlb_flush_vmid);
-KVM_NVHE_ALIAS(__kvm_tlb_flush_vmid_ipa);
-
 /* Symbols defined in vgic-v3-sr.c (not yet compiled with nVHE build rules). */
 KVM_NVHE_ALIAS(__vgic_v3_get_ich_vtr_el2);
 KVM_NVHE_ALIAS(__vgic_v3_init_lrs);
@@ -116,6 +110,14 @@ KVM_NVHE_ALIAS(__hyp_stub_vectors);
 /* IDMAP TCR_EL1.T0SZ as computed by the EL1 init code */
 KVM_NVHE_ALIAS(idmap_t0sz);
 
+/* Kernel symbol used by icache_is_vpipt(). */
+KVM_NVHE_ALIAS(__icache_flags);
+
+/* Kernel symbols needed for cpus_have_final/const_caps checks. */
+KVM_NVHE_ALIAS(arm64_const_caps_ready);
+KVM_NVHE_ALIAS(cpu_hwcap_keys);
+KVM_NVHE_ALIAS(cpu_hwcaps);
+
 #endif /* CONFIG_KVM */
 
 #endif /* __ARM64_KERNEL_IMAGE_VARS_H */
index 8b0cf85..87d3cce 100644 (file)
@@ -14,7 +14,7 @@ obj-$(CONFIG_KVM) += hyp.o vhe/ nvhe/
 obj-$(CONFIG_KVM_INDIRECT_VECTORS) += smccc_wa.o
 
 hyp-y := vgic-v3-sr.o timer-sr.o aarch32.o vgic-v2-cpuif-proxy.o sysreg-sr.o \
-        debug-sr.o entry.o switch.o fpsimd.o tlb.o
+        debug-sr.o entry.o switch.o fpsimd.o
 
 # KVM code is run at a different exception code with a different map, so
 # compiler instrumentation that inserts callbacks or checks into the code may
index bf2d8de..a5316e9 100644 (file)
@@ -6,7 +6,7 @@
 asflags-y := -D__KVM_NVHE_HYPERVISOR__
 ccflags-y := -D__KVM_NVHE_HYPERVISOR__
 
-obj-y := hyp-init.o ../hyp-entry.o
+obj-y := tlb.o hyp-init.o ../hyp-entry.o
 
 obj-y := $(patsubst %.o,%.hyp.o,$(obj-y))
 extra-y := $(patsubst %.hyp.o,%.hyp.tmp.o,$(obj-y))
similarity index 61%
rename from arch/arm64/kvm/hyp/tlb.c
rename to arch/arm64/kvm/hyp/nvhe/tlb.c
index d063a57..deb48c8 100644 (file)
@@ -4,64 +4,16 @@
  * Author: Marc Zyngier <marc.zyngier@arm.com>
  */
 
-#include <linux/irqflags.h>
-
 #include <asm/kvm_hyp.h>
 #include <asm/kvm_mmu.h>
 #include <asm/tlbflush.h>
 
 struct tlb_inv_context {
-       unsigned long   flags;
        u64             tcr;
-       u64             sctlr;
 };
 
-static void __hyp_text __tlb_switch_to_guest_vhe(struct kvm *kvm,
-                                                struct tlb_inv_context *cxt)
-{
-       u64 val;
-
-       local_irq_save(cxt->flags);
-
-       if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
-               /*
-                * For CPUs that are affected by ARM errata 1165522 or 1530923,
-                * we cannot trust stage-1 to be in a correct state at that
-                * point. Since we do not want to force a full load of the
-                * vcpu state, we prevent the EL1 page-table walker to
-                * allocate new TLBs. This is done by setting the EPD bits
-                * in the TCR_EL1 register. We also need to prevent it to
-                * allocate IPA->PA walks, so we enable the S1 MMU...
-                */
-               val = cxt->tcr = read_sysreg_el1(SYS_TCR);
-               val |= TCR_EPD1_MASK | TCR_EPD0_MASK;
-               write_sysreg_el1(val, SYS_TCR);
-               val = cxt->sctlr = read_sysreg_el1(SYS_SCTLR);
-               val |= SCTLR_ELx_M;
-               write_sysreg_el1(val, SYS_SCTLR);
-       }
-
-       /*
-        * With VHE enabled, we have HCR_EL2.{E2H,TGE} = {1,1}, and
-        * most TLB operations target EL2/EL0. In order to affect the
-        * guest TLBs (EL1/EL0), we need to change one of these two
-        * bits. Changing E2H is impossible (goodbye TTBR1_EL2), so
-        * let's flip TGE before executing the TLB operation.
-        *
-        * ARM erratum 1165522 requires some special handling (again),
-        * as we need to make sure both stages of translation are in
-        * place before clearing TGE. __load_guest_stage2() already
-        * has an ISB in order to deal with this.
-        */
-       __load_guest_stage2(kvm);
-       val = read_sysreg(hcr_el2);
-       val &= ~HCR_TGE;
-       write_sysreg(val, hcr_el2);
-       isb();
-}
-
-static void __hyp_text __tlb_switch_to_guest_nvhe(struct kvm *kvm,
-                                                 struct tlb_inv_context *cxt)
+static void __hyp_text __tlb_switch_to_guest(struct kvm *kvm,
+                                            struct tlb_inv_context *cxt)
 {
        if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
                u64 val;
@@ -84,37 +36,8 @@ static void __hyp_text __tlb_switch_to_guest_nvhe(struct kvm *kvm,
        asm(ALTERNATIVE("isb", "nop", ARM64_WORKAROUND_SPECULATIVE_AT));
 }
 
-static void __hyp_text __tlb_switch_to_guest(struct kvm *kvm,
-                                            struct tlb_inv_context *cxt)
-{
-       if (has_vhe())
-               __tlb_switch_to_guest_vhe(kvm, cxt);
-       else
-               __tlb_switch_to_guest_nvhe(kvm, cxt);
-}
-
-static void __hyp_text __tlb_switch_to_host_vhe(struct kvm *kvm,
-                                               struct tlb_inv_context *cxt)
-{
-       /*
-        * We're done with the TLB operation, let's restore the host's
-        * view of HCR_EL2.
-        */
-       write_sysreg(0, vttbr_el2);
-       write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2);
-       isb();
-
-       if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
-               /* Restore the registers to what they were */
-               write_sysreg_el1(cxt->tcr, SYS_TCR);
-               write_sysreg_el1(cxt->sctlr, SYS_SCTLR);
-       }
-
-       local_irq_restore(cxt->flags);
-}
-
-static void __hyp_text __tlb_switch_to_host_nvhe(struct kvm *kvm,
-                                                struct tlb_inv_context *cxt)
+static void __hyp_text __tlb_switch_to_host(struct kvm *kvm,
+                                           struct tlb_inv_context *cxt)
 {
        write_sysreg(0, vttbr_el2);
 
@@ -126,15 +49,6 @@ static void __hyp_text __tlb_switch_to_host_nvhe(struct kvm *kvm,
        }
 }
 
-static void __hyp_text __tlb_switch_to_host(struct kvm *kvm,
-                                           struct tlb_inv_context *cxt)
-{
-       if (has_vhe())
-               __tlb_switch_to_host_vhe(kvm, cxt);
-       else
-               __tlb_switch_to_host_nvhe(kvm, cxt);
-}
-
 void __hyp_text __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)
 {
        struct tlb_inv_context cxt;
@@ -183,7 +97,7 @@ void __hyp_text __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)
         * The moral of this story is: if you have a VPIPT I-cache, then
         * you should be running with VHE enabled.
         */
-       if (!has_vhe() && icache_is_vpipt())
+       if (icache_is_vpipt())
                __flush_icache_all();
 
        __tlb_switch_to_host(kvm, &cxt);
index 323029e..704140f 100644 (file)
@@ -6,7 +6,7 @@
 asflags-y := -D__KVM_VHE_HYPERVISOR__
 ccflags-y := -D__KVM_VHE_HYPERVISOR__
 
-obj-y := ../hyp-entry.o
+obj-y := tlb.o ../hyp-entry.o
 
 # KVM code is run at a different exception code with a different map, so
 # compiler instrumentation that inserts callbacks or checks into the code may
diff --git a/arch/arm64/kvm/hyp/vhe/tlb.c b/arch/arm64/kvm/hyp/vhe/tlb.c
new file mode 100644 (file)
index 0000000..b275101
--- /dev/null
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2015 - ARM Ltd
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ */
+
+#include <linux/irqflags.h>
+
+#include <asm/kvm_hyp.h>
+#include <asm/kvm_mmu.h>
+#include <asm/tlbflush.h>
+
+struct tlb_inv_context {
+       unsigned long   flags;
+       u64             tcr;
+       u64             sctlr;
+};
+
+static void __tlb_switch_to_guest(struct kvm *kvm, struct tlb_inv_context *cxt)
+{
+       u64 val;
+
+       local_irq_save(cxt->flags);
+
+       if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
+               /*
+                * For CPUs that are affected by ARM errata 1165522 or 1530923,
+                * we cannot trust stage-1 to be in a correct state at that
+                * point. Since we do not want to force a full load of the
+                * vcpu state, we prevent the EL1 page-table walker to
+                * allocate new TLBs. This is done by setting the EPD bits
+                * in the TCR_EL1 register. We also need to prevent it to
+                * allocate IPA->PA walks, so we enable the S1 MMU...
+                */
+               val = cxt->tcr = read_sysreg_el1(SYS_TCR);
+               val |= TCR_EPD1_MASK | TCR_EPD0_MASK;
+               write_sysreg_el1(val, SYS_TCR);
+               val = cxt->sctlr = read_sysreg_el1(SYS_SCTLR);
+               val |= SCTLR_ELx_M;
+               write_sysreg_el1(val, SYS_SCTLR);
+       }
+
+       /*
+        * With VHE enabled, we have HCR_EL2.{E2H,TGE} = {1,1}, and
+        * most TLB operations target EL2/EL0. In order to affect the
+        * guest TLBs (EL1/EL0), we need to change one of these two
+        * bits. Changing E2H is impossible (goodbye TTBR1_EL2), so
+        * let's flip TGE before executing the TLB operation.
+        *
+        * ARM erratum 1165522 requires some special handling (again),
+        * as we need to make sure both stages of translation are in
+        * place before clearing TGE. __load_guest_stage2() already
+        * has an ISB in order to deal with this.
+        */
+       __load_guest_stage2(kvm);
+       val = read_sysreg(hcr_el2);
+       val &= ~HCR_TGE;
+       write_sysreg(val, hcr_el2);
+       isb();
+}
+
+static void __tlb_switch_to_host(struct kvm *kvm, struct tlb_inv_context *cxt)
+{
+       /*
+        * We're done with the TLB operation, let's restore the host's
+        * view of HCR_EL2.
+        */
+       write_sysreg(0, vttbr_el2);
+       write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2);
+       isb();
+
+       if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
+               /* Restore the registers to what they were */
+               write_sysreg_el1(cxt->tcr, SYS_TCR);
+               write_sysreg_el1(cxt->sctlr, SYS_SCTLR);
+       }
+
+       local_irq_restore(cxt->flags);
+}
+
+void __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)
+{
+       struct tlb_inv_context cxt;
+
+       dsb(ishst);
+
+       /* Switch to requested VMID */
+       __tlb_switch_to_guest(kvm, &cxt);
+
+       /*
+        * We could do so much better if we had the VA as well.
+        * Instead, we invalidate Stage-2 for this IPA, and the
+        * whole of Stage-1. Weep...
+        */
+       ipa >>= 12;
+       __tlbi(ipas2e1is, ipa);
+
+       /*
+        * We have to ensure completion of the invalidation at Stage-2,
+        * since a table walk on another CPU could refill a TLB with a
+        * complete (S1 + S2) walk based on the old Stage-2 mapping if
+        * the Stage-1 invalidation happened first.
+        */
+       dsb(ish);
+       __tlbi(vmalle1is);
+       dsb(ish);
+       isb();
+
+       __tlb_switch_to_host(kvm, &cxt);
+}
+
+void __kvm_tlb_flush_vmid(struct kvm *kvm)
+{
+       struct tlb_inv_context cxt;
+
+       dsb(ishst);
+
+       /* Switch to requested VMID */
+       __tlb_switch_to_guest(kvm, &cxt);
+
+       __tlbi(vmalls12e1is);
+       dsb(ish);
+       isb();
+
+       __tlb_switch_to_host(kvm, &cxt);
+}
+
+void __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu)
+{
+       struct kvm *kvm = vcpu->kvm;
+       struct tlb_inv_context cxt;
+
+       /* Switch to requested VMID */
+       __tlb_switch_to_guest(kvm, &cxt);
+
+       __tlbi(vmalle1);
+       dsb(nsh);
+       isb();
+
+       __tlb_switch_to_host(kvm, &cxt);
+}
+
+void __kvm_flush_vm_context(void)
+{
+       dsb(ishst);
+       __tlbi(alle1is);
+
+       /*
+        * VIPT and PIPT caches are not affected by VMID, so no maintenance
+        * is necessary across a VMID rollover.
+        *
+        * VPIPT caches constrain lookup and maintenance to the active VMID,
+        * so we need to invalidate lines with a stale VMID to avoid an ABA
+        * race after multiple rollovers.
+        *
+        */
+       if (icache_is_vpipt())
+               asm volatile("ic ialluis");
+
+       dsb(ish);
+}