Re: [PATCH PATCH 9/9] x86/rfds: Exclude P-only parts from the RFDS affected list

Andrew Cooper
2024-06-17T09:43:11Z

On 17/06/2024 10:12 am, Pawan Gupta wrote:
> diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
> index 7e3b09b0f82c..73ec66321758 100644
> --- a/arch/x86/kernel/cpu/common.c
> +++ b/arch/x86/kernel/cpu/common.c
> @@ -1209,6 +1209,9 @@ static const __initconst struct x86_cpu_id cpu_vuln_whitelist[] = {
> #define VULNBL_INTEL_STEPPINGS(vfm, steppings, issues) \
> X86_MATCH_VFM_STEPPINGS(INTEL_##vfm, steppings, issues)
>
> +#define VULNBL_INTEL_CPU_TYPE(vfm, cpu_type, issues) \
> + X86_MATCH_VFM_CPU_TYPE(INTEL_##vfm, cpu_type, issues)
> +
> #define VULNBL_AMD(family, blacklist) \
> VULNBL(AMD, family, X86_MODEL_ANY, blacklist)
>
> @@ -1255,9 +1258,7 @@ static const struct x86_cpu_id cpu_vuln_blacklist[] __initconst = {
> VULNBL_INTEL(TIGERLAKE, GDS),
> VULNBL_INTEL(LAKEFIELD, MMIO | MMIO_SBDS | RETBLEED),
> VULNBL_INTEL(ROCKETLAKE, MMIO | RETBLEED | GDS),
> - VULNBL_INTEL(ALDERLAKE, RFDS),
> VULNBL_INTEL(ALDERLAKE_L, RFDS),
> - VULNBL_INTEL(RAPTORLAKE, RFDS),
> VULNBL_INTEL(RAPTORLAKE_P, RFDS),
> VULNBL_INTEL(RAPTORLAKE_S, RFDS),
> VULNBL_INTEL(ATOM_GRACEMONT, RFDS),
> @@ -1271,6 +1272,8 @@ static const struct x86_cpu_id cpu_vuln_blacklist[] __initconst = {
> /* Match more than Vendor/Family/Model */
> VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPINGS(0x0, 0x0), MMIO | RETBLEED),
> VULNBL_INTEL (COMETLAKE_L, MMIO | MMIO_SBDS | RETBLEED | GDS),
> + VULNBL_INTEL_CPU_TYPE (RAPTORLAKE, X86_CPU_TYPE_INTEL_ATOM, RFDS),
> + VULNBL_INTEL_CPU_TYPE (ALDERLAKE, X86_CPU_TYPE_INTEL_ATOM, RFDS),

How does this work?

Being __initconst, this is only evaluated on the BSP.

P-only and mixed P/E systems won't see X86_CPU_TYPE_INTEL_ATOM, even if
there are ATOM APs to bring up later.

~Andrew