Re: [PATCH v3 1/3] Correct asm VMXOFF side effects

[Randy Dunlap]

On 7/4/20 1:38 PM, David P. Reed wrote:
> Tell gcc that VMXOFF instruction clobbers condition codes
> and memory when executed.
> Also, correct original comments to remove kernel-doc syntax
> per Randy Dunlap's request.

Looks good. Thanks.  For the comment changes:
Acked-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>

> Suggested-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> Signed-off-by: David P. Reed <dpreed@xxxxxxxxxxxx>
> ---
>  arch/x86/include/asm/virtext.h | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/include/asm/virtext.h b/arch/x86/include/asm/virtext.h
> index 9aad0e0876fb..0ede8d04535a 100644
> --- a/arch/x86/include/asm/virtext.h
> +++ b/arch/x86/include/asm/virtext.h
> @@ -30,7 +30,7 @@ static inline int cpu_has_vmx(void)
>  }
>  
>  
> -/** Disable VMX on the current CPU
> +/* Disable VMX on the current CPU
>   *
>   * vmxoff causes a undefined-opcode exception if vmxon was not run
>   * on the CPU previously. Only call this function if you know VMX
> @@ -38,7 +38,7 @@ static inline int cpu_has_vmx(void)
>   */
>  static inline void cpu_vmxoff(void)
>  {
> -	asm volatile ("vmxoff");
> +	asm volatile ("vmxoff" ::: "cc", "memory");
>  	cr4_clear_bits(X86_CR4_VMXE);
>  }
>  
> @@ -47,7 +47,7 @@ static inline int cpu_vmx_enabled(void)
>  	return __read_cr4() & X86_CR4_VMXE;
>  }
>  
> -/** Disable VMX if it is enabled on the current CPU
> +/* Disable VMX if it is enabled on the current CPU
>   *
>   * You shouldn't call this if cpu_has_vmx() returns 0.
>   */
> @@ -57,7 +57,7 @@ static inline void __cpu_emergency_vmxoff(void)
>  		cpu_vmxoff();
>  }
>  
> -/** Disable VMX if it is supported and enabled on the current CPU
> +/* Disable VMX if it is supported and enabled on the current CPU
>   */
>  static inline void cpu_emergency_vmxoff(void)
>  {
> 


-- 
~Randy