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x86/cpu/amd: Correct the microcode table for Zenbleed

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The good revisions are tied to exact steppings, meaning it's not valid to
match on model number alone, let alone a range.

This is probably only a latent issue.  From public microcode archives, the
following CPUs exist 17-30-00, 17-60-00, 17-70-00 and would be captured by the
model ranges.  They're likely pre-production steppings, and likely didn't get
Zenbleed microcode, but it's still incorrect to compare them to a different
steppings revision.

Either way, convert the logic to use x86_match_min_microcode_rev(), which is
the preferred mechanism.

Fixes: 522b1d6921 ("x86/cpu/amd: Add a Zenbleed fix")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: x86@kernel.org
Link: https://patch.msgid.link/20251126130352.880424-1-andrew.cooper3@citrix.com
This commit is contained in:
Andrew Cooper 2025-11-26 13:03:52 +00:00 committed by Ingo Molnar
parent 8f0b4cce44
commit fb7bfa31b8
1 changed files with 9 additions and 21 deletions
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30
arch/x86/kernel/cpu/amd.c
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@ -951,26 +951,14 @@ static void init_amd_zen1(struct cpuinfo_x86 *c)
}
}
static bool cpu_has_zenbleed_microcode(void)
{
u32 good_rev = 0;
switch (boot_cpu_data.x86_model) {
case 0x30 ... 0x3f: good_rev = 0x0830107b; break;
case 0x60 ... 0x67: good_rev = 0x0860010c; break;
case 0x68 ... 0x6f: good_rev = 0x08608107; break;
case 0x70 ... 0x7f: good_rev = 0x08701033; break;
case 0xa0 ... 0xaf: good_rev = 0x08a00009; break;
default:
return false;
}
if (boot_cpu_data.microcode < good_rev)
return false;
return true;
}
static const struct x86_cpu_id amd_zenbleed_microcode[] = {
ZEN_MODEL_STEP_UCODE(0x17, 0x31, 0x0, 0x0830107b),
ZEN_MODEL_STEP_UCODE(0x17, 0x60, 0x1, 0x0860010c),
ZEN_MODEL_STEP_UCODE(0x17, 0x68, 0x1, 0x08608107),
ZEN_MODEL_STEP_UCODE(0x17, 0x71, 0x0, 0x08701033),
ZEN_MODEL_STEP_UCODE(0x17, 0xa0, 0x0, 0x08a00009),
{}
};
static void zen2_zenbleed_check(struct cpuinfo_x86 *c)
{
@ -980,7 +968,7 @@ static void zen2_zenbleed_check(struct cpuinfo_x86 *c)
if (!cpu_has(c, X86_FEATURE_AVX))
return;
if (!cpu_has_zenbleed_microcode()) {
if (!x86_match_min_microcode_rev(amd_zenbleed_microcode)) {
pr_notice_once("Zenbleed: please update your microcode for the most optimal fix\n");
msr_set_bit(MSR_AMD64_DE_CFG, MSR_AMD64_DE_CFG_ZEN2_FP_BACKUP_FIX_BIT);
} else {