KVM: x86: Ensure all logical CPUs have consistent reserved cr4 bits

Check the current CPU's reserved cr4 bits against the mask calculated
for the boot CPU to ensure consistent behavior across all CPUs.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8a907cd7b1e182c3d7c7c2f37e59beefad55a3a1..960b886e1e436090bff3589c1111535f22702c67 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9461,6 +9461,13 @@ void kvm_arch_hardware_unsetup(void)
 
 int kvm_arch_check_processor_compat(void)
 {
+       struct cpuinfo_x86 *c = &cpu_data(smp_processor_id());
+
+       WARN_ON(!irqs_disabled());
+
+       if (kvm_host_cr4_reserved_bits(c) != cr4_reserved_bits)
+               return -EIO;
+
        return kvm_x86_ops->check_processor_compatibility();
 }