[PATCH v2 0/2] x86/tdx: Port I/O emulation fixes

[Kiryl Shutsemau (Meta)]

This series addresses two technical inaccuracies in the TDX guest port
I/O emulation code reported by Borys Tsyrulnikov.

The first patch fixes an off-by-one error in the GENMASK() macro usage
where the mask was being calculated as one bit too wide (e.g. 9 bits for
an 8-bit operation).

The second patch ensures that 32-bit port I/O operations (INL) correctly
zero-extend the result to the full 64-bit RAX register, as required by
the x86 architecture. Currently, the emulation preserves the upper 32
bits of RAX during such operations.

Both issues were introduced in the initial implementation of the runtime
hypercalls for port I/O.

v1: https://lore.kernel.org/all/20260331112430.71425-1-kas@xxxxxxxxxx/

Changes in v2:
  - Rephrase the size check in handle_in() as "if (size == 4)" for
    readability (Kuppuswamy)
  - Add Link: to the bug report on both patches (Kuppuswamy)
  - Collect Reviewed-by tags (Kai Huang, Kuppuswamy Sathyanarayanan)
  - Rebase onto v7.1-rc1

Kiryl Shutsemau (Meta) (2):
  x86/tdx: Fix off-by-one in port I/O handling
  x86/tdx: Fix zero-extension for 32-bit port I/O

 arch/x86/coco/tdx/tdx.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)


base-commit: 254f49634ee16a731174d2ae34bc50bd5f45e731
-- 
2.51.2