Commit a8b6fda3 authored May 23, 2017 by Jim Mattson Committed by Radim Krčmář Jun 07, 2017

kvm: vmx: Do not disable intercepts for BNDCFGS



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: da8999d3 ("KVM: x86: Intel MPX vmx and msr handle")
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

parent 9d643f63

arch/x86/kvm/vmx.c

+0 −1

Original line number	Diff line number	Diff line
		@@ -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);

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