On Mon, Apr 10, 2023, Xiaoyao Li wrote:
> Directly use vcpu->arch.cr4 is not recommended since it gets stale value
> if the cr4 is not available.
>
> Use kvm_read_cr4() instead to ensure correct value.
>
> Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
> ---
> arch/x86/kvm/vmx/vmx.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index d7bf14abdba1..befa2486836b 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -3431,7 +3431,7 @@ static bool vmx_is_valid_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
>
> void vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
> {
> - unsigned long old_cr4 = vcpu->arch.cr4;
> + unsigned long old_cr4 = kvm_read_cr4(vcpu);
Ha! I've been tempted to change this multiple times, but always thought I was
just being a bit obsessive :-)
Patches look good, but I'm going to hold them for 6.5 just in case this somehow
causes a problem, e.g. if there's a bizzaro nested path that "works" because KVM
_doesn't_ decache info from the current VMCS.
