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| author | Paolo Bonzini <pbonzini@redhat.com> | 2014-03-06 02:19:52 +0400 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2014-03-17 15:21:39 +0400 |
| commit | 93c4adc7afedf9b0ec190066d45b6d67db5270da (patch) | |
| tree | 8b941c7e959fab7a677df0d6d7c4052ec468342d /arch/x86/kvm/vmx.c | |
| parent | 36be0b9deb23161e9eba962c215aece551113a15 (diff) | |
| download | linux-93c4adc7afedf9b0ec190066d45b6d67db5270da.tar.xz | |
KVM: x86: handle missing MPX in nested virtualization
When doing nested virtualization, we may be able to read BNDCFGS but
still not be allowed to write to GUEST_BNDCFGS in the VMCS. Guard
writes to the field with vmx_mpx_supported(), and similarly hide the
MSR from userspace if the processor does not support the field.
We could work around this with the generic MSR save/load machinery,
but there is only a limited number of MSR save/load slots and it is
not really worthwhile to waste one for a scenario that should not
happen except in the nested virtualization case.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/vmx.c')
| -rw-r--r-- | arch/x86/kvm/vmx.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index c95bea17fc1e..1320e0f8e611 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -729,6 +729,7 @@ static unsigned long nested_ept_get_cr3(struct kvm_vcpu *vcpu); static u64 construct_eptp(unsigned long root_hpa); static void kvm_cpu_vmxon(u64 addr); static void kvm_cpu_vmxoff(void); +static bool vmx_mpx_supported(void); static int vmx_set_tss_addr(struct kvm *kvm, unsigned int addr); static void vmx_set_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg); @@ -2501,6 +2502,8 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata) data = vmcs_readl(GUEST_SYSENTER_ESP); break; case MSR_IA32_BNDCFGS: + if (!vmx_mpx_supported()) + return 1; data = vmcs_read64(GUEST_BNDCFGS); break; case MSR_IA32_FEATURE_CONTROL: @@ -2572,6 +2575,8 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) vmcs_writel(GUEST_SYSENTER_ESP, data); break; case MSR_IA32_BNDCFGS: + if (!vmx_mpx_supported()) + return 1; vmcs_write64(GUEST_BNDCFGS, data); break; case MSR_IA32_TSC: |