Messages in this thread Patch in this message | | | From | Ramakrishna Saripalli <> | Subject | [PATCH 2/5] x86/speculation: Implement support for PSFD detection and reporting | Date | Tue, 6 Apr 2021 10:50:01 -0500 |
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From: Ramakrishna Saripalli <rk.saripalli@amd.com>
All AMD processors that support Predictive Store Forwarding (PSF) provide a CPUID bit to detect support for mitigation of this feature. This bit is referred to as PSFD (Predictive Store Forwarding Disable)
If CPU advertises PSFD: - Advertise a generic feature (X86_FEATURE_PSFD) in Linux capability flags to indicate PSF mitigation is available.
- Advertise X86_BUG_PSF in Linux bug bits to indicate that CPU is affected by PSF security risks.
Signed-off-by: Ramakrishna Saripalli<rk.saripalli@amd.com> --- arch/x86/kernel/cpu/common.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index ab640abe26b6..4e604d58f3b3 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -893,6 +893,9 @@ static void init_speculation_control(struct cpuinfo_x86 *c) set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL); clear_cpu_cap(c, X86_FEATURE_VIRT_SSBD); } + + if (cpu_has(c, X86_FEATURE_AMD_PSFD)) + set_cpu_cap(c, X86_FEATURE_PSFD); } void get_cpu_cap(struct cpuinfo_x86 *c) @@ -1154,6 +1157,9 @@ static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c) !cpu_has(c, X86_FEATURE_AMD_SSB_NO)) setup_force_cpu_bug(X86_BUG_SPEC_STORE_BYPASS); + if (cpu_has(c, X86_FEATURE_AMD_PSFD)) + setup_force_cpu_bug(X86_BUG_PSF); + if (ia32_cap & ARCH_CAP_IBRS_ALL) setup_force_cpu_cap(X86_FEATURE_IBRS_ENHANCED); -- 2.25.1
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