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authorBoris Ostrovsky <boris.ostrovsky@oracle.com>2019-12-05 01:30:51 +0000
committerPaolo Bonzini <pbonzini@redhat.com>2020-01-30 18:45:55 +0100
commit917248144db5d7320655dbb41d3af0b8a0f3d589 (patch)
tree4c865f9aeb61137847ce9d283bc33febded17714 /arch/x86
parent1eff70a9abd46f175defafd29bc17ad456f398a7 (diff)
x86/kvm: Cache gfn to pfn translation
__kvm_map_gfn()'s call to gfn_to_pfn_memslot() is * relatively expensive * in certain cases (such as when done from atomic context) cannot be called Stashing gfn-to-pfn mapping should help with both cases. This is part of CVE-2019-3016. Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Joao Martins <joao.m.martins@oracle.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/include/asm/kvm_host.h1
-rw-r--r--arch/x86/kvm/x86.c10
2 files changed, 11 insertions, 0 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index b79cd6aa4075..f48a306e1d66 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -689,6 +689,7 @@ struct kvm_vcpu_arch {
u64 last_steal;
struct gfn_to_hva_cache stime;
struct kvm_steal_time steal;
+ struct gfn_to_pfn_cache cache;
} st;
u64 tsc_offset;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8c9369151e9f..0795bc876abc 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9088,6 +9088,9 @@ static void fx_init(struct kvm_vcpu *vcpu)
void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
{
void *wbinvd_dirty_mask = vcpu->arch.wbinvd_dirty_mask;
+ struct gfn_to_pfn_cache *cache = &vcpu->arch.st.cache;
+
+ kvm_release_pfn(cache->pfn, cache->dirty, cache);
kvmclock_reset(vcpu);
@@ -9761,11 +9764,18 @@ out_free:
void kvm_arch_memslots_updated(struct kvm *kvm, u64 gen)
{
+ struct kvm_vcpu *vcpu;
+ int i;
+
/*
* memslots->generation has been incremented.
* mmio generation may have reached its maximum value.
*/
kvm_mmu_invalidate_mmio_sptes(kvm, gen);
+
+ /* Force re-initialization of steal_time cache */
+ kvm_for_each_vcpu(i, vcpu, kvm)
+ kvm_vcpu_kick(vcpu);
}
int kvm_arch_prepare_memory_region(struct kvm *kvm,

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