Re: [PATCH v3 1/2] x86/tdx: Fix off-by-one in port I/O handling

[Edgecombe, Rick P]

On Wed, 2026-05-27 at 13:05 +0100, Kiryl Shutsemau (Meta) wrote:
> handle_in() and handle_out() in arch/x86/coco/tdx/tdx.c use:
> 
>     u64 mask = GENMASK(BITS_PER_BYTE * size, 0);
> 
> GENMASK(h, l) includes bit h. For size=1 (INB), this produces
> GENMASK(8, 0) = 0x1FF (9 bits) instead of GENMASK(7, 0) = 0xFF (8
> bits). The mask is one bit too wide for all I/O sizes.
> 
> Fix the mask calculation.
> 
> Fixes: 03149948832a ("x86/tdx: Port I/O: Add runtime hypercalls")
> Reported-by: Borys Tsyrulnikov <tsyrulnikov.borys@xxxxxxxxx>
> Link:
> https://lore.kernel.org/all/CAKw_Dz96rfSQc6Rn+9QBcUFHhmkK+9zu+P=bxowfZwxrATCBRg@xxxxxxxxxxxxxx/
> Signed-off-by: Kiryl Shutsemau (Meta) <kas@xxxxxxxxxx>
> Reviewed-by: Kai Huang <kai.huang@xxxxxxxxx>
> Reviewed-by: Kuppuswamy Sathyanarayanan
> <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx

Reviewed-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx>