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x86/cpu: Fix AMD erratum #1485 on Zen4-based CPUs

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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>
This commit is contained in:
Borislav Petkov (AMD) 2023-10-07 12:57:02 +02:00 committed by Ksawlii
parent c39a71f91d
commit 7c2487e4f5
2 changed files with 15 additions and 2 deletions
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9
arch/x86/include/asm/msr-index.h
View file

@ -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

8
arch/x86/kernel/cpu/amd.c
View file

@ -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 *c)
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