Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

[tomoyo/tomoyo-test1.git] / arch / x86 / kvm / cpuid.c

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index d343268..0544e30 100644 (file)
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -11,6 +11,7 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/kvm_host.h>
+#include "linux/lockdep.h"
 #include <linux/export.h>
 #include <linux/vmalloc.h>
 #include <linux/uaccess.h>
@@ -84,6 +85,18 @@ static inline struct kvm_cpuid_entry2 *cpuid_entry2_find(
        struct kvm_cpuid_entry2 *e;
        int i;
 
+       /*
+        * KVM has a semi-arbitrary rule that querying the guest's CPUID model
+        * with IRQs disabled is disallowed.  The CPUID model can legitimately
+        * have over one hundred entries, i.e. the lookup is slow, and IRQs are
+        * typically disabled in KVM only when KVM is in a performance critical
+        * path, e.g. the core VM-Enter/VM-Exit run loop.  Nothing will break
+        * if this rule is violated, this assertion is purely to flag potential
+        * performance issues.  If this fires, consider moving the lookup out
+        * of the hotpath, e.g. by caching information during CPUID updates.
+        */
+       lockdep_assert_irqs_enabled();
+
        for (i = 0; i < nent; i++) {
                e = &entries[i];
 
@@ -312,6 +325,27 @@ static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
 {
        struct kvm_lapic *apic = vcpu->arch.apic;
        struct kvm_cpuid_entry2 *best;
+       bool allow_gbpages;
+
+       BUILD_BUG_ON(KVM_NR_GOVERNED_FEATURES > KVM_MAX_NR_GOVERNED_FEATURES);
+       bitmap_zero(vcpu->arch.governed_features.enabled,
+                   KVM_MAX_NR_GOVERNED_FEATURES);
+
+       /*
+        * If TDP is enabled, let the guest use GBPAGES if they're supported in
+        * hardware.  The hardware page walker doesn't let KVM disable GBPAGES,
+        * i.e. won't treat them as reserved, and KVM doesn't redo the GVA->GPA
+        * walk for performance and complexity reasons.  Not to mention KVM
+        * _can't_ solve the problem because GVA->GPA walks aren't visible to
+        * KVM once a TDP translation is installed.  Mimic hardware behavior so
+        * that KVM's is at least consistent, i.e. doesn't randomly inject #PF.
+        * If TDP is disabled, honor *only* guest CPUID as KVM has full control
+        * and can install smaller shadow pages if the host lacks 1GiB support.
+        */
+       allow_gbpages = tdp_enabled ? boot_cpu_has(X86_FEATURE_GBPAGES) :
+                                     guest_cpuid_has(vcpu, X86_FEATURE_GBPAGES);
+       if (allow_gbpages)
+               kvm_governed_feature_set(vcpu, X86_FEATURE_GBPAGES);
 
        best = kvm_find_cpuid_entry(vcpu, 1);
        if (best && apic) {
@@ -647,7 +681,8 @@ void kvm_set_cpu_caps(void)
        );
 
        kvm_cpu_cap_init_kvm_defined(CPUID_7_1_EDX,
-               F(AVX_VNNI_INT8) | F(AVX_NE_CONVERT) | F(PREFETCHITI)
+               F(AVX_VNNI_INT8) | F(AVX_NE_CONVERT) | F(PREFETCHITI) |
+               F(AMX_COMPLEX)
        );
 
        kvm_cpu_cap_mask(CPUID_D_1_EAX,
@@ -1154,6 +1189,9 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
                cpuid_entry_override(entry, CPUID_8000_0001_EDX);
                cpuid_entry_override(entry, CPUID_8000_0001_ECX);
                break;
+       case 0x80000005:
+               /*  Pass host L1 cache and TLB info. */
+               break;
        case 0x80000006:
                /* Drop reserved bits, pass host L2 cache and TLB info. */
                entry->edx &= ~GENMASK(17, 16);