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From: Michael Roth <michael.roth@amd.com>
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Subject: [PATCH v1 05/26] x86/mtrr: Don't print errors if MtrrFixDramModEn is set when SNP enabled
Date: Sat, 30 Dec 2023 10:19:33 -0600
Message-ID: <20231230161954.569267-6-michael.roth@amd.com>
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From: Ashish Kalra <ashish.kalra@amd.com>

SNP enabled platforms require the MtrrFixDramModeEn bit to be set across
all CPUs when SNP is enabled. Therefore, don't print error messages when
MtrrFixDramModeEn is set when bringing CPUs online.

Reported-by: Jeremi Piotrowski <jpiotrowski@linux.microsoft.com>
Closes: https://lore.kernel.org/kvm/68b2d6bf-bce7-47f9-bebb-2652cc923ff9@linux.microsoft.com/
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
---
 arch/x86/kernel/cpu/mtrr/generic.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index d3524778a545..422a4ddc2ab7 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -108,6 +108,9 @@ static inline void k8_check_syscfg_dram_mod_en(void)
 	      (boot_cpu_data.x86 >= 0x0f)))
 		return;
 
+	if (cpu_feature_enabled(X86_FEATURE_SEV_SNP))
+		return;
+
 	rdmsr(MSR_AMD64_SYSCFG, lo, hi);
 	if (lo & K8_MTRRFIXRANGE_DRAM_MODIFY) {
 		pr_err(FW_WARN "MTRR: CPU %u: SYSCFG[MtrrFixDramModEn]"
-- 
2.25.1