x86/CPU/AMD: Disable INVLPGB on Zen2

AMD Cyan Skillfish (Family 17h, Model 47h, Stepping 0h) has an issue
that causes system oopses and panics when performing TLB flush using
INVLPGB.

However, the problem is that that machine has misconfigured CPUID and
should not report the INVLPGB bit in the first place. So zap the
kernel's representation of the flag so that nothing gets confused.

  [ bp: Massage. ]

Fixes: 767ae437a32d ("x86/mm: Add INVLPGB feature and Kconfig entry")
Signed-off-by: Mikhail Paulyshka <me@mixaill.net>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/1ebe845b-322b-4929-9093-b41074e9e939@mixaill.net

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index e1c4661f443012cb8415e0fd6d26519224d0c67f..1b1ff60e9202aba99a1d711510a9001a90fa7450 100644 (file)
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -937,6 +937,9 @@ static void init_amd_zen2(struct cpuinfo_x86 *c)
                msr_clear_bit(MSR_AMD64_CPUID_FN_7, 18);
                pr_emerg("RDSEED is not reliable on this platform; disabling.\n");
        }
+
+       /* Correct misconfigured CPUID on some clients. */
+       clear_cpu_cap(c, X86_FEATURE_INVLPGB);
 }
 
 static void init_amd_zen3(struct cpuinfo_x86 *c)