On Mon, Sep 23, 2024 at 03:41:12PM +0000, John Allen wrote:

A problem was introduced with f69759b ("x86/CPU/AMD: Move Zenbleed check to the Zen2 init function") where a bit in the DE_CFG MSR is getting set after a microcode late load.

The problem is that the microcode late load path calls into amd_check_microcode and subsequently zen2_zenbleed_check. Since the patch removes the cpu_has_amd_erratum check from zen2_zenbleed_check, this will cause all non-Zen2 cpus to go through the function and set the bit in the DE_CFG MSR.

Call into the zenbleed fix path on Zen2 cpus only.

Fixes: f69759be251d ("x86/CPU/AMD: Move Zenbleed check to the Zen2 init function")

Should probably go into stable as well.

Cc: stable@vger.kernel.org

Signed-off-by: John Allen john.allen@amd.com

arch/x86/kernel/cpu/amd.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 015971adadfc..368344e1394b 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -1202,5 +1202,6 @@ void amd_check_microcode(void) if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD) return;

• on_each_cpu(zenbleed_check_cpu, NULL, 1);

• if (boot_cpu_has(X86_FEATURE_ZEN2))

• on_each_cpu(zenbleed_check_cpu, NULL, 1);
  

}

2.34.1