On Wed, May 22, 2019 at 07:45:44PM -0400, Krish Sadhukhan wrote:
> Signed-off-by: Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx>
> Reviewed-by: Karl Heubaum <karl.heubaum@xxxxxxxxxx>
> ---
> lib/x86/processor.h | 8 ++++++++
> x86/vmexit.c | 2 +-
> 2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/lib/x86/processor.h b/lib/x86/processor.h
> index 15237a5..2ca988e 100644
> --- a/lib/x86/processor.h
> +++ b/lib/x86/processor.h
> @@ -476,4 +476,12 @@ static inline void set_bit(int bit, u8 *addr)
> : "+m" (*addr) : "Ir" (bit) : "cc", "memory");
> }
>
> +static inline int efer_nx_enabled(void)
cpu_has_efer_nx() would be more appropriate. Most readers would expect
"enabled" to mean we're checking MSR_EFER.NX==1.
This can have a boolean return value.
> +{
> + if (cpuid(0x80000001).d & (1 << 20))
> + return 1;
> + else
> + return 0;
> +}
This can simply be:
return cpuid(0x80000001).d & (1 << 20);
or if gcc complains about boolean stuff:
return !!(cpuid(0x80000001).d & (1 << 20));
> +
> #endif
> diff --git a/x86/vmexit.c b/x86/vmexit.c
> index c12dd24..7053a46 100644
> --- a/x86/vmexit.c
> +++ b/x86/vmexit.c
> @@ -526,7 +526,7 @@ static bool do_test(struct test *test)
>
> static void enable_nx(void *junk)
> {
> - if (cpuid(0x80000001).d & (1 << 20))
> + if (efer_nx_enabled())
> wrmsr(MSR_EFER, rdmsr(MSR_EFER) | EFER_NX_MASK);
> }
>
> --
> 2.20.1
>
