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KVM: vmx: use MSR_IA32_TSX_CTRL to hard-disable TSX on guest that lack it

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If X86_FEATURE_RTM is disabled, the guest should not be able to access
MSR_IA32_TSX_CTRL.  We can therefore use it in KVM to force all
transactions from the guest to abort.

Tested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2019-11-18 12:23:01 -05:00
parent c11f83e062
commit b07a5c53d4
1 changed files with 30 additions and 14 deletions
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44
arch/x86/kvm/vmx/vmx.c
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@ -639,6 +639,23 @@ struct shared_msr_entry *find_msr_entry(struct vcpu_vmx *vmx, u32 msr)
return NULL;
}
static int vmx_set_guest_msr(struct vcpu_vmx *vmx, struct shared_msr_entry *msr, u64 data)
{
int ret = 0;
u64 old_msr_data = msr->data;
msr->data = data;
if (msr - vmx->guest_msrs < vmx->save_nmsrs) {
preempt_disable();
ret = kvm_set_shared_msr(msr->index, msr->data,
msr->mask);
preempt_enable();
if (ret)
msr->data = old_msr_data;
}
return ret;
}
void loaded_vmcs_init(struct loaded_vmcs *loaded_vmcs)
{
vmcs_clear(loaded_vmcs->vmcs);
@ -2174,20 +2191,10 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
default:
find_shared_msr:
msr = find_msr_entry(vmx, msr_index);
if (msr) {
u64 old_msr_data = msr->data;
msr->data = data;
if (msr - vmx->guest_msrs < vmx->save_nmsrs) {
preempt_disable();
ret = kvm_set_shared_msr(msr->index, msr->data,
msr->mask);
preempt_enable();
if (ret)
msr->data = old_msr_data;
}
break;
}
ret = kvm_set_msr_common(vcpu, msr_info);
if (msr)
ret = vmx_set_guest_msr(vmx, msr, data);
else
ret = kvm_set_msr_common(vcpu, msr_info);
}
return ret;
@ -7142,6 +7149,15 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
if (boot_cpu_has(X86_FEATURE_INTEL_PT) &&
guest_cpuid_has(vcpu, X86_FEATURE_INTEL_PT))
update_intel_pt_cfg(vcpu);
if (boot_cpu_has(X86_FEATURE_RTM)) {
struct shared_msr_entry *msr;
msr = find_msr_entry(vmx, MSR_IA32_TSX_CTRL);
if (msr) {
bool enabled = guest_cpuid_has(vcpu, X86_FEATURE_RTM);
vmx_set_guest_msr(vmx, msr, enabled ? 0 : TSX_CTRL_RTM_DISABLE);
}
}
}
static void vmx_set_supported_cpuid(u32 func, struct kvm_cpuid_entry2 *entry)