Re: [PATCH v7 05/10] x86/tdx: Handle port I/O

Thomas Gleixner
2021-10-17T19:58:39Z

On Tue, Oct 05 2021 at 13:41, Kuppuswamy Sathyanarayanan wrote:
> \
> static inline void outs##bwl(int port, const void *addr, unsigned long count) \
> { \
> - if (sev_key_active()) { \
> + if (sev_key_active() || \
> + cc_platform_has(CC_ATTR_GUEST_UNROLL_STRING_IO)) { \

Instead of adding an extra check, can you please replace that
sev_key_active() with cc_platform_has() completely?

> +/*
> + * tdx_handle_early_io() cannot be re-used in #VE handler for handling
> + * I/O because the way of handling string I/O is different between
> + * normal and early I/O case. Also, once trace support is enabled,
> + * tdx_handle_io() will be extended to use trace calls which is also
> + * not valid for early I/O cases.
> + */
> +static void tdx_handle_io(struct pt_regs *regs, u32 exit_qual)
> +{
> + struct tdx_hypercall_output outh;
> + int out, size, port, ret;
> + bool string;
> + u64 mask;
> +
> + string = VE_IS_IO_STRING(exit_qual);
> +
> + /* I/O strings ops are unrolled at build time. */

Fancy. The compiler can evaluate sev_key_active() and
cc_platform_has() at build time?

Thanks,

tglx