| Message ID | 20170523185254.98780-1-jmattson@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
2017-05-23 11:52-0700, Jim Mattson: > The MSR permission bitmaps are shared by all VMs. However, some VMs > may not be configured to support MPX, even when the host does. If the > host supports VMX and the guest does not, we should intercept accesses > to the BNDCFGS MSR, so that we can synthesize a #GP > fault. Furthermore, if the host does not support MPX and the > "ignore_msrs" kvm kernel parameter is set, then we should intercept > accesses to the BNDCFGS MSR, so that we can skip over the rdmsr/wrmsr > without raising a #GP fault. > > Fixes: da8999d31818fdc8 ("KVM: x86: Intel MPX vmx and msr handle") > Signed-off-by: Jim Mattson <jmattson@google.com> > --- IIUC, we don't even need faster accesses as BNDCFGS MSR should usually be written once per boot and never read, Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
2017-05-23 11:52-0700, Jim Mattson: > The MSR permission bitmaps are shared by all VMs. However, some VMs > may not be configured to support MPX, even when the host does. If the > host supports VMX and the guest does not, we should intercept accesses > to the BNDCFGS MSR, so that we can synthesize a #GP > fault. Furthermore, if the host does not support MPX and the > "ignore_msrs" kvm kernel parameter is set, then we should intercept > accesses to the BNDCFGS MSR, so that we can skip over the rdmsr/wrmsr > without raising a #GP fault. > > Fixes: da8999d31818fdc8 ("KVM: x86: Intel MPX vmx and msr handle") > Signed-off-by: Jim Mattson <jmattson@google.com> > --- Queued all, thanks.
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index c6f4ad44aa95..763d27ee00fb 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -6547,7 +6547,6 @@ static __init int hardware_setup(void) vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_CS, false); vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_ESP, false); vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_EIP, false); - vmx_disable_intercept_for_msr(MSR_IA32_BNDCFGS, true); memcpy(vmx_msr_bitmap_legacy_x2apic_apicv, vmx_msr_bitmap_legacy, PAGE_SIZE);
The MSR permission bitmaps are shared by all VMs. However, some VMs may not be configured to support MPX, even when the host does. If the host supports VMX and the guest does not, we should intercept accesses to the BNDCFGS MSR, so that we can synthesize a #GP fault. Furthermore, if the host does not support MPX and the "ignore_msrs" kvm kernel parameter is set, then we should intercept accesses to the BNDCFGS MSR, so that we can skip over the rdmsr/wrmsr without raising a #GP fault. Fixes: da8999d31818fdc8 ("KVM: x86: Intel MPX vmx and msr handle") Signed-off-by: Jim Mattson <jmattson@google.com> --- arch/x86/kvm/vmx.c | 1 - 1 file changed, 1 deletion(-)