Commit a6bd811f authored by Boris Ostrovsky's avatar Boris Ostrovsky Committed by Paolo Bonzini
Browse files

x86/KVM: Clean up host's steal time structure 



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: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: default avatarJoao Martins <joao.m.martins@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent b0431382

arch/x86/include/asm/kvm_host.h

+1 −2
Original line number Diff line number Diff line
@@ -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;

arch/x86/kvm/x86.c

+3 −8
Original line number Diff line number Diff line
@@ -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);

}

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