From: Boris Ostrovsky boris.ostrovsky@oracle.com

Now that we are mapping kvm_steal_time from the guest directly we don't need keep a copy of it in kvm_vcpu_arch.st. The same is true for the stime field.

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 --- arch/x86/include/asm/kvm_host.h | 3 +-- arch/x86/kvm/x86.c | 11 +++-------- 2 files changed, 4 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index f48a306e..4925bdb 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -685,10 +685,9 @@ struct kvm_vcpu_arch { bool pvclock_set_guest_stopped_request;

struct { + u8 preempted; u64 msr_val; u64 last_steal; - struct gfn_to_hva_cache stime; - struct kvm_steal_time steal; struct gfn_to_pfn_cache cache; } st;

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index f1845df..a0381ec 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2604,7 +2604,7 @@ static void record_steal_time(struct kvm_vcpu *vcpu) if (xchg(&st->preempted, 0) & KVM_VCPU_FLUSH_TLB) kvm_vcpu_flush_tlb(vcpu, false);

- vcpu->arch.st.steal.preempted = 0; + vcpu->arch.st.preempted = 0;

if (st->version & 1) st->version += 1; /* first time write, random junk */ @@ -2788,11 +2788,6 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) if (data & KVM_STEAL_RESERVED_MASK) return 1;

- if (kvm_gfn_to_hva_cache_init(vcpu->kvm, &vcpu->arch.st.stime, - data & KVM_STEAL_VALID_BITS, - sizeof(struct kvm_steal_time))) - return 1; - vcpu->arch.st.msr_val = data;

if (!(data & KVM_MSR_ENABLED)) @@ -3509,7 +3504,7 @@ static void kvm_steal_time_set_preempted(struct kvm_vcpu *vcpu) if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED)) return;

- if (vcpu->arch.st.steal.preempted) + if (vcpu->arch.st.preempted) return;

if (kvm_map_gfn(vcpu, vcpu->arch.st.msr_val >> PAGE_SHIFT, &map, @@ -3519,7 +3514,7 @@ static void kvm_steal_time_set_preempted(struct kvm_vcpu *vcpu) st = map.hva + offset_in_page(vcpu->arch.st.msr_val & KVM_STEAL_VALID_BITS);

- st->preempted = vcpu->arch.st.steal.preempted = KVM_VCPU_PREEMPTED; + st->preempted = vcpu->arch.st.preempted = KVM_VCPU_PREEMPTED;

kvm_unmap_gfn(vcpu, &map, &vcpu->arch.st.cache, true, true); }