* [PATCH] kvm: vmx: allow host to access guest MSR_IA32_BNDCFGS
@ 2017-07-04 2:27 Haozhong Zhang
2017-07-04 9:31 ` Paolo Bonzini
0 siblings, 1 reply; 2+ messages in thread
From: Haozhong Zhang @ 2017-07-04 2:27 UTC (permalink / raw)
To: kvm; +Cc: Paolo Bonzini, rkrcmar, Haozhong Zhang
It's free for host applications, such as QEMU, to access guest
MSR_IA32_BNDCFGS in VMCS, even though MPX is disabled in guest cpuid.
Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
---
arch/x86/kvm/vmx.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index fb0471268a14..b4cfdcfdc1c1 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3196,7 +3196,8 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
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;
@@ -3278,7 +3279,8 @@ 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 (!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))
--
2.11.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] kvm: vmx: allow host to access guest MSR_IA32_BNDCFGS
2017-07-04 2:27 [PATCH] kvm: vmx: allow host to access guest MSR_IA32_BNDCFGS Haozhong Zhang
@ 2017-07-04 9:31 ` Paolo Bonzini
0 siblings, 0 replies; 2+ messages in thread
From: Paolo Bonzini @ 2017-07-04 9:31 UTC (permalink / raw)
To: Haozhong Zhang, kvm; +Cc: rkrcmar, stable
On 04/07/2017 04:27, Haozhong Zhang wrote:
> It's free for host applications, such as QEMU, to access guest
> MSR_IA32_BNDCFGS in VMCS, even though MPX is disabled in guest cpuid.
>
> Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Thanks, committed to kvm.git with
Cc: stable@vger.kernel.org
Paolo
> ---
> arch/x86/kvm/vmx.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index fb0471268a14..b4cfdcfdc1c1 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -3196,7 +3196,8 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
> 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;
> @@ -3278,7 +3279,8 @@ 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 (!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))
>
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2017-07-04 9:31 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-07-04 2:27 [PATCH] kvm: vmx: allow host to access guest MSR_IA32_BNDCFGS Haozhong Zhang
2017-07-04 9:31 ` Paolo Bonzini
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.