From: Jim Mattson Date: Fri, 22 Nov 2019 23:43:55 +0000 (-0800) Subject: kvm: nVMX: Relax guest IA32_FEATURE_CONTROL constraints X-Git-Tag: v5.5-rc1~182^2~1 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=85c9aae9ac8b228f2134b56d4fc743afc446947a;p=thirdparty%2Fkernel%2Flinux.git kvm: nVMX: Relax guest IA32_FEATURE_CONTROL constraints Commit 37e4c997dadf ("KVM: VMX: validate individual bits of guest MSR_IA32_FEATURE_CONTROL") broke the KVM_SET_MSRS ABI by instituting new constraints on the data values that kvm would accept for the guest MSR, IA32_FEATURE_CONTROL. Perhaps these constraints should have been opt-in via a new KVM capability, but they were applied indiscriminately, breaking at least one existing hypervisor. Relax the constraints to allow either or both of FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX and FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX to be set when nVMX is enabled. This change is sufficient to fix the aforementioned breakage. Fixes: 37e4c997dadf ("KVM: VMX: validate individual bits of guest MSR_IA32_FEATURE_CONTROL") Signed-off-by: Jim Mattson Reviewed-by: Liran Alon Signed-off-by: Paolo Bonzini --- diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index d39475e2d44e8..d175429c91b01 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -7115,10 +7115,12 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu) if (nested_vmx_allowed(vcpu)) to_vmx(vcpu)->msr_ia32_feature_control_valid_bits |= + FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX | FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX; else to_vmx(vcpu)->msr_ia32_feature_control_valid_bits &= - ~FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX; + ~(FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX | + FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX); if (nested_vmx_allowed(vcpu)) { nested_vmx_cr_fixed1_bits_update(vcpu);