KVM: VMX: Use VMX feature flag to query BIOS enabling

Replace KVM's manual checks on IA32_FEAT_CTL with a query on the boot
CPU's MSR_IA32_FEAT_CTL and VMX feature flags.  The MSR_IA32_FEAT_CTL
indicates that IA32_FEAT_CTL has been configured and that dependent
features are accurately reflected in cpufeatures, e.g. the VMX flag is
now cleared during boot if VMX isn't fully enabled via IA32_FEAT_CTL,
including the case where the MSR isn't supported.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20191221044513.21680-16-sean.j.christopherson@intel.com
This commit is contained in:
Sean Christopherson 2019-12-20 20:45:09 -08:00 committed by Borislav Petkov
parent 21bd3467a5
commit a4d0b2fdbc

View File

@ -2204,31 +2204,8 @@ static __init int cpu_has_kvm_support(void)
static __init int vmx_disabled_by_bios(void)
{
u64 msr;
rdmsrl(MSR_IA32_FEAT_CTL, msr);
if (unlikely(!(msr & FEAT_CTL_LOCKED)))
return 1;
/* launched w/ TXT and VMX disabled */
if (!(msr & FEAT_CTL_VMX_ENABLED_INSIDE_SMX) &&
tboot_enabled())
return 1;
/* launched w/o TXT and VMX only enabled w/ TXT */
if (!(msr & FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX) &&
(msr & FEAT_CTL_VMX_ENABLED_INSIDE_SMX) &&
!tboot_enabled()) {
pr_warn("kvm: disable TXT in the BIOS or "
"activate TXT before enabling KVM\n");
return 1;
}
/* launched w/o TXT and VMX disabled */
if (!(msr & FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX) &&
!tboot_enabled())
return 1;
return 0;
return !boot_cpu_has(X86_FEATURE_MSR_IA32_FEAT_CTL) ||
!boot_cpu_has(X86_FEATURE_VMX);
}
static void kvm_cpu_vmxon(u64 addr)