5.10-stable review patch. If anyone has any objections, please let me know.
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From: Borislav Petkov (AMD) bp@alien8.de
commit f454b18e07f518bcd0c05af17a2239138bff52de upstream.
Fix erratum #1485 on Zen4 parts where running with STIBP disabled can cause an #UD exception. The performance impact of the fix is negligible.
Reported-by: René Rebe rene@exactcode.de Signed-off-by: Borislav Petkov (AMD) bp@alien8.de Tested-by: René Rebe rene@exactcode.de Cc: stable@kernel.org Link: https://lore.kernel.org/r/D99589F4-BC5D-430B-87B2-72C20370CF57@exactcode.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/include/asm/msr-index.h | 9 +++++++-- arch/x86/kernel/cpu/amd.c | 8 ++++++++ 2 files changed, 15 insertions(+), 2 deletions(-)
--- a/arch/x86/include/asm/msr-index.h +++ b/arch/x86/include/asm/msr-index.h @@ -541,12 +541,17 @@
#define MSR_AMD64_VIRT_SPEC_CTRL 0xc001011f
-/* Fam 17h MSRs */ -#define MSR_F17H_IRPERF 0xc00000e9 +/* Zen4 */ +#define MSR_ZEN4_BP_CFG 0xc001102e +#define MSR_ZEN4_BP_CFG_SHARED_BTB_FIX_BIT 5
+/* Zen 2 */ #define MSR_ZEN2_SPECTRAL_CHICKEN 0xc00110e3 #define MSR_ZEN2_SPECTRAL_CHICKEN_BIT BIT_ULL(1)
+/* Fam 17h MSRs */ +#define MSR_F17H_IRPERF 0xc00000e9 + /* Fam 16h MSRs */ #define MSR_F16H_L2I_PERF_CTL 0xc0010230 #define MSR_F16H_L2I_PERF_CTR 0xc0010231 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -81,6 +81,10 @@ static const int amd_div0[] = AMD_LEGACY_ERRATUM(AMD_MODEL_RANGE(0x17, 0x00, 0x0, 0x2f, 0xf), AMD_MODEL_RANGE(0x17, 0x50, 0x0, 0x5f, 0xf));
+static const int amd_erratum_1485[] = + AMD_LEGACY_ERRATUM(AMD_MODEL_RANGE(0x19, 0x10, 0x0, 0x1f, 0xf), + AMD_MODEL_RANGE(0x19, 0x60, 0x0, 0xaf, 0xf)); + static bool cpu_has_amd_erratum(struct cpuinfo_x86 *cpu, const int *erratum) { int osvw_id = *erratum++; @@ -1178,6 +1182,10 @@ static void init_amd(struct cpuinfo_x86 pr_notice_once("AMD Zen1 DIV0 bug detected. Disable SMT for full protection.\n"); setup_force_cpu_bug(X86_BUG_DIV0); } + + if (!cpu_has(c, X86_FEATURE_HYPERVISOR) && + cpu_has_amd_erratum(c, amd_erratum_1485)) + msr_set_bit(MSR_ZEN4_BP_CFG, MSR_ZEN4_BP_CFG_SHARED_BTB_FIX_BIT); }
#ifdef CONFIG_X86_32