On 10/17/2023 3:14 AM, Kai Huang wrote:
> Some SEAMCALLs use the RDRAND hardware and can fail for the same reasons
> as RDRAND. Use the kernel RDRAND retry logic for them.
>
> There are three __seamcall*() variants. Do the SEAMCALL retry in common
> code and add a wrapper for each of them.
>
> Signed-off-by: Kai Huang <kai.huang@xxxxxxxxx>
> Reviewed-by: Kirill A. Shutemov <kirll.shutemov@xxxxxxxxxxxxxxx>
> ---
>
> v13 -> v14:
> - Use real function sc_retry() instead of using macros. (Dave)
> - Added Kirill's tag.
>
> v12 -> v13:
> - New implementation due to TDCALL assembly series.
> ---
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx
> arch/x86/include/asm/tdx.h | 26 ++++++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>
> diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
> index a252328734c7..d624aa25aab0 100644
> --- a/arch/x86/include/asm/tdx.h
> +++ b/arch/x86/include/asm/tdx.h
> @@ -24,6 +24,11 @@
> #define TDX_SEAMCALL_GP (TDX_SW_ERROR | X86_TRAP_GP)
> #define TDX_SEAMCALL_UD (TDX_SW_ERROR | X86_TRAP_UD)
>
> +/*
> + * TDX module SEAMCALL leaf function error codes
> + */
> +#define TDX_RND_NO_ENTROPY 0x8000020300000000ULL
> +
> #ifndef __ASSEMBLY__
>
> /*
> @@ -82,6 +87,27 @@ u64 __seamcall(u64 fn, struct tdx_module_args *args);
> u64 __seamcall_ret(u64 fn, struct tdx_module_args *args);
> u64 __seamcall_saved_ret(u64 fn, struct tdx_module_args *args);
>
> +#include <asm/archrandom.h>
> +
> +typedef u64 (*sc_func_t)(u64 fn, struct tdx_module_args *args);
> +
> +static inline u64 sc_retry(sc_func_t func, u64 fn,
> + struct tdx_module_args *args)
> +{
> + int retry = RDRAND_RETRY_LOOPS;
> + u64 ret;
> +
> + do {
> + ret = func(fn, args);
> + } while (ret == TDX_RND_NO_ENTROPY && --retry);
> +
> + return ret;
> +}
> +
> +#define seamcall(_fn, _args) sc_retry(__seamcall, (_fn), (_args))
> +#define seamcall_ret(_fn, _args) sc_retry(__seamcall_ret, (_fn), (_args))
> +#define seamcall_saved_ret(_fn, _args) sc_retry(__seamcall_saved_ret, (_fn), (_args))
> +
> bool platform_tdx_enabled(void);
> #else
> static inline bool platform_tdx_enabled(void) { return false; }
--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer
