On 07/18/17 17:06 +0200, gregkh@xxxxxxxxxxxxxxxxxxx wrote: > > The patch below does not apply to the 4.12-stable tree. > If someone wants it applied there, or to any other stable or longterm > tree, then please email the backport, including the original git commit > id to <stable@xxxxxxxxxxxxxxx>. > > thanks, > > greg k-h Hi Paolo and Greg, I think the following patches should be backported as well before applying mine: a8b6fda38f80 kvm: vmx: Do not disable intercepts for BNDCFGS 4439af9f911a kvm: x86: Guest BNDCFGS requires guest MPX support 4531662d1abf kvm: vmx: Check value written to IA32_BNDCFGS Haozhong > > ------------------ original commit in Linus's tree ------------------ > > From 691bd4340bef49cf7e5855d06cf24444b5bf2d85 Mon Sep 17 00:00:00 2001 > From: Haozhong Zhang <haozhong.zhang@xxxxxxxxx> > Date: Tue, 4 Jul 2017 10:27:41 +0800 > Subject: [PATCH] kvm: vmx: allow host to access guest MSR_IA32_BNDCFGS > > 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. > > Cc: stable@xxxxxxxxxxxxxxx > Signed-off-by: Haozhong Zhang <haozhong.zhang@xxxxxxxxx> > Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> > > 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)) >