[PATCH v5 16/19] KVM: VMX: Check for full VMX support when verifying CPU compatibility

Sean Christopherson
2019-12-21T04:46:43Z

Explicitly check the current CPU's IA32_FEAT_CTL and VMX feature flags
when verifying compatibility across physical CPUs. This effectively
adds a check on IA32_FEAT_CTL to ensure that VMX is fully enabled on
all CPUs.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/vmx/vmx.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 06e0e5262704..cdb4bf50ee14 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6838,6 +6838,12 @@ static int __init vmx_check_processor_compat(void)
struct vmcs_config vmcs_conf;
struct vmx_capability vmx_cap;

+ if (!this_cpu_has(X86_FEATURE_MSR_IA32_FEAT_CTL) ||
+ !this_cpu_has(X86_FEATURE_VMX)) {
+ pr_err("kvm: VMX is disabled on CPU %d\n", smp_processor_id());
+ return -EIO;
+ }
+
if (setup_vmcs_config(&vmcs_conf, &vmx_cap) < 0)
return -EIO;
if (nested)
--
2.24.1