Re: [PATCH v10 1/6] x86/cpufeatures: Add X86_FEATURE_RMPOPT feature flag
Borislav Petkov <[email protected]>
| Newsgroups | dev.linux.lists.linux-coco,org.kernel.vger.kvm,org.kernel.vger.linux-crypto,org.kernel.vger.linux-kernel |
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| Message-ID | <20260720211259.GCal6PW5aCGieR5j3W@fat_crate.local> |
On Tue, Jun 30, 2026 at 06:09:44PM +0000, Ashish Kalra wrote: > arch/x86/include/asm/cpufeatures.h | 2 +- > arch/x86/kernel/cpu/scattered.c | 1 + > tools/arch/x86/include/asm/cpufeatures.h | 2 +- Yeah, apparently we don't do the tools/ change anymore: https://lore.kernel.org/r/[email protected] Final version: Author: Ashish Kalra <[email protected]> Date: Tue Jun 30 18:09:44 2026 +0000 x86/cpufeatures: Add X86_FEATURE_RMPOPT feature flag Add a flag indicating whether RMPOPT instruction is supported. RMPOPT is a new instruction that reduces the performance overhead of RMP checks for the hypervisor and non-SNP guests by allowing those checks to be skipped when 1-GB memory regions are known to contain no SEV-SNP guest memory. For more information on the RMPOPT instruction, see the AMD64 RMPOPT technical documentation. [ bp: Zap respective tools/ change. ] Suggested-by: Borislav Petkov (AMD) <[email protected]> Signed-off-by: Ashish Kalra <[email protected]> Signed-off-by: Borislav Petkov (AMD) <[email protected]> Reviewed-by: Dave Hansen <[email protected]> Reviewed-by: Ackerley Tng <[email protected]> Link: https://patch.msgid.link/39e9ee269a572c516a3f4e937bfe12d00697d5e6.1782841284.git.ashish.kalra@amd.com diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index 3d0940a3b9f3..dbccde9ee5cd 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -76,7 +76,7 @@ #define X86_FEATURE_K8 ( 3*32+ 4) /* Opteron, Athlon64 */ #define X86_FEATURE_ZEN5 ( 3*32+ 5) /* CPU based on Zen5 microarchitecture */ #define X86_FEATURE_ZEN6 ( 3*32+ 6) /* CPU based on Zen6 microarchitecture */ -/* Free ( 3*32+ 7) */ +#define X86_FEATURE_RMPOPT ( 3*32+ 7) /* Support for AMD RMPOPT instruction */ #define X86_FEATURE_CONSTANT_TSC ( 3*32+ 8) /* "constant_tsc" TSC ticks at a constant rate */ /* free: was #define X86_FEATURE_UP ( 3*32+ 9) * "up" SMP kernel running on UP */ #define X86_FEATURE_ART ( 3*32+10) /* "art" Always running timer (ART) */ diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c index 937129ce6a96..021c0bf22de2 100644 --- a/arch/x86/kernel/cpu/scattered.c +++ b/arch/x86/kernel/cpu/scattered.c @@ -67,6 +67,7 @@ static const struct cpuid_bit cpuid_bits[] = { { X86_FEATURE_PERFMON_V2, CPUID_EAX, 0, 0x80000022, 0 }, { X86_FEATURE_AMD_LBR_V2, CPUID_EAX, 1, 0x80000022, 0 }, { X86_FEATURE_AMD_LBR_PMC_FREEZE, CPUID_EAX, 2, 0x80000022, 0 }, + { X86_FEATURE_RMPOPT, CPUID_EDX, 0, 0x80000025, 0 }, { X86_FEATURE_AMD_HTR_CORES, CPUID_EAX, 30, 0x80000026, 0 }, { 0, 0, 0, 0, 0 } }; -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette