Commit 263e55949d89 for kernel

commit 263e55949d8902a6a09bdb92a1ab6a3f67231abe
Author: Sandipan Das <sandipan.das@amd.com>
Date:   Fri Apr 18 11:49:40 2025 +0530

    x86/cpu/amd: Fix workaround for erratum 1054

    Erratum 1054 affects AMD Zen processors that are a part of Family 17h
    Models 00-2Fh and the workaround is to not set HWCR[IRPerfEn]. However,
    when X86_FEATURE_ZEN1 was introduced, the condition to detect unaffected
    processors was incorrectly changed in a way that the IRPerfEn bit gets
    set only for unaffected Zen 1 processors.

    Ensure that HWCR[IRPerfEn] is set for all unaffected processors. This
    includes a subset of Zen 1 (Family 17h Models 30h and above) and all
    later processors. Also clear X86_FEATURE_IRPERF on affected processors
    so that the IRPerfCount register is not used by other entities like the
    MSR PMU driver.

    Fixes: 232afb557835 ("x86/CPU/AMD: Add X86_FEATURE_ZEN1")
    Signed-off-by: Sandipan Das <sandipan.das@amd.com>
    Signed-off-by: Ingo Molnar <mingo@kernel.org>
    Acked-by: Borislav Petkov <bp@alien8.de>
    Cc: stable@vger.kernel.org
    Link: https://lore.kernel.org/r/caa057a9d6f8ad579e2f1abaa71efbd5bd4eaf6d.1744956467.git.sandipan.das@amd.com

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index a839ff506f45..2b36379ff675 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -869,6 +869,16 @@ static void init_amd_zen1(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);
+
+	/*
+	 * Turn off the Instructions Retired free counter on machines that are
+	 * susceptible to erratum #1054 "Instructions Retired Performance
+	 * Counter May Be Inaccurate".
+	 */
+	if (c->x86_model < 0x30) {
+		msr_clear_bit(MSR_K7_HWCR, MSR_K7_HWCR_IRPERF_EN_BIT);
+		clear_cpu_cap(c, X86_FEATURE_IRPERF);
+	}
 }

 static bool cpu_has_zenbleed_microcode(void)
@@ -1052,13 +1062,8 @@ static void init_amd(struct cpuinfo_x86 *c)
 	if (!cpu_feature_enabled(X86_FEATURE_XENPV))
 		set_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS);

-	/*
-	 * Turn on the Instructions Retired free counter on machines not
-	 * susceptible to erratum #1054 "Instructions Retired Performance
-	 * Counter May Be Inaccurate".
-	 */
-	if (cpu_has(c, X86_FEATURE_IRPERF) &&
-	    (boot_cpu_has(X86_FEATURE_ZEN1) && c->x86_model > 0x2f))
+	/* Enable the Instructions Retired free counter */
+	if (cpu_has(c, X86_FEATURE_IRPERF))
 		msr_set_bit(MSR_K7_HWCR, MSR_K7_HWCR_IRPERF_EN_BIT);

 	check_null_seg_clears_base(c);