Re: [PATCH kvm-unit-tests] x86: Added LA57 support to is_canonical

[Paolo Bonzini <pbonzini@redhat.com>]

On 13/08/21 13:18, Lara Lazier wrote:
> In case LA57 is enabled, the function is_canonical would need to
> check if the address is correctly sign-extended from bit 57 (instead of 48)
> to bit 63.
> 
> Signed-off-by: Lara Lazier <laramglazier@gmail.com>
> ---
>   lib/x86/processor.h | 5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/x86/processor.h b/lib/x86/processor.h
> index a08ea1f..3b43fc4 100644
> --- a/lib/x86/processor.h
> +++ b/lib/x86/processor.h
> @@ -640,7 +640,10 @@ static inline void write_pkru(u32 pkru)
>   
>   static inline bool is_canonical(u64 addr)
>   {
> -	return (s64)(addr << 16) >> 16 == addr;
> +	int va_width = (raw_cpuid(0x80000008, 0).a & 0xff00) >> 8;
> +	int shift_amt = 64 - va_width;
> +
> +	return (s64)(addr << shift_amt) >> shift_amt == addr;
>   }
>   
>   static inline void clear_bit(int bit, u8 *addr)
> 

Queued, thanks.

Paolo