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KVM: x86: Inject #GP with the right rip on efer writes 

This patch fixes a bug in the KVM efer-msr write path. If a
guest writes to a reserved efer bit the set_efer function
injects the #GP directly. The architecture dependent wrmsr
function does not see this, assumes success and advances the
rip. This results in a #GP in the guest with the wrong rip.
This patch fixes this by reporting efer write errors back to
the architectural wrmsr function.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Roedel, Joerg 2010-05-06 11:38:43 +02:00 committed by Avi Kivity
parent 0d945bd935
commit b69e8caef5
1 changed files with 12 additions and 19 deletions
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31
arch/x86/kvm/x86.c
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@ -683,37 +683,29 @@ static u32 emulated_msrs[] = {
MSR_IA32_MISC_ENABLE,
};
static void set_efer(struct kvm_vcpu *vcpu, u64 efer)
static int set_efer(struct kvm_vcpu *vcpu, u64 efer)
{
if (efer & efer_reserved_bits) {
kvm_inject_gp(vcpu, 0);
return;
}
if (efer & efer_reserved_bits)
return 1;
if (is_paging(vcpu)
&& (vcpu->arch.efer & EFER_LME) != (efer & EFER_LME)) {
kvm_inject_gp(vcpu, 0);
return;
}
&& (vcpu->arch.efer & EFER_LME) != (efer & EFER_LME))
return 1;
if (efer & EFER_FFXSR) {
struct kvm_cpuid_entry2 *feat;
feat = kvm_find_cpuid_entry(vcpu, 0x80000001, 0);
if (!feat || !(feat->edx & bit(X86_FEATURE_FXSR_OPT))) {
kvm_inject_gp(vcpu, 0);
return;
}
if (!feat || !(feat->edx & bit(X86_FEATURE_FXSR_OPT)))
return 1;
}
if (efer & EFER_SVME) {
struct kvm_cpuid_entry2 *feat;
feat = kvm_find_cpuid_entry(vcpu, 0x80000001, 0);
if (!feat || !(feat->ecx & bit(X86_FEATURE_SVM))) {
kvm_inject_gp(vcpu, 0);
return;
}
if (!feat || !(feat->ecx & bit(X86_FEATURE_SVM)))
return 1;
}
kvm_x86_ops->set_efer(vcpu, efer);
@ -725,6 +717,8 @@ static void set_efer(struct kvm_vcpu *vcpu, u64 efer)
vcpu->arch.mmu.base_role.nxe = (efer & EFER_NX) && !tdp_enabled;
kvm_mmu_reset_context(vcpu);
return 0;
}
void kvm_enable_efer_bits(u64 mask)
@ -1153,8 +1147,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data)
{
switch (msr) {
case MSR_EFER:
set_efer(vcpu, data);
break;
return set_efer(vcpu, data);
case MSR_K7_HWCR:
data &= ~(u64)0x40; /* ignore flush filter disable */
data &= ~(u64)0x100; /* ignore ignne emulation enable */