4.11-stable review patch. If anyone has any objections, please let me know.
------------------ From: Haozhong Zhang <[email protected]> commit 691bd4340bef49cf7e5855d06cf24444b5bf2d85 upstream. It's easier for host applications, such as QEMU, if they can always access guest MSR_IA32_BNDCFGS in VMCS, even though MPX is disabled in guest cpuid. Signed-off-by: Haozhong Zhang <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/x86/kvm/vmx.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -3200,7 +3200,8 @@ static int vmx_get_msr(struct kvm_vcpu * msr_info->data = vmcs_readl(GUEST_SYSENTER_ESP); break; case MSR_IA32_BNDCFGS: - if (!kvm_mpx_supported() || !guest_cpuid_has_mpx(vcpu)) + if (!kvm_mpx_supported() || + (!msr_info->host_initiated && !guest_cpuid_has_mpx(vcpu))) return 1; msr_info->data = vmcs_read64(GUEST_BNDCFGS); break; @@ -3282,7 +3283,8 @@ static int vmx_set_msr(struct kvm_vcpu * vmcs_writel(GUEST_SYSENTER_ESP, data); break; case MSR_IA32_BNDCFGS: - if (!kvm_mpx_supported() || !guest_cpuid_has_mpx(vcpu)) + if (!kvm_mpx_supported() || + (!msr_info->host_initiated && !guest_cpuid_has_mpx(vcpu))) return 1; if (is_noncanonical_address(data & PAGE_MASK) || (data & MSR_IA32_BNDCFGS_RSVD))
