linux-kernel - [PATCH v1 05/26] x86/mtrr: Don't print errors if MtrrFixDramModEn is set when SNP enabled

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20231230161954.569267-6-michael.roth@amd.com>
Date: Sat, 30 Dec 2023 10:19:33 -0600
From: Michael Roth <michael.roth@....com>
To: <x86@...nel.org>
CC: <kvm@...r.kernel.org>, <linux-coco@...ts.linux.dev>, <linux-mm@...ck.org>,
	<linux-crypto@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<tglx@...utronix.de>, <mingo@...hat.com>, <jroedel@...e.de>,
	<thomas.lendacky@....com>, <hpa@...or.com>, <ardb@...nel.org>,
	<pbonzini@...hat.com>, <seanjc@...gle.com>, <vkuznets@...hat.com>,
	<jmattson@...gle.com>, <luto@...nel.org>, <dave.hansen@...ux.intel.com>,
	<slp@...hat.com>, <pgonda@...gle.com>, <peterz@...radead.org>,
	<srinivas.pandruvada@...ux.intel.com>, <rientjes@...gle.com>,
	<tobin@....com>, <bp@...en8.de>, <vbabka@...e.cz>, <kirill@...temov.name>,
	<ak@...ux.intel.com>, <tony.luck@...el.com>,
	<sathyanarayanan.kuppuswamy@...ux.intel.com>, <alpergun@...gle.com>,
	<jarkko@...nel.org>, <ashish.kalra@....com>, <nikunj.dadhania@....com>,
	<pankaj.gupta@....com>, <liam.merwick@...cle.com>, <zhi.a.wang@...el.com>,
	Jeremi Piotrowski <jpiotrowski@...ux.microsoft.com>
Subject: [PATCH v1 05/26] x86/mtrr: Don't print errors if MtrrFixDramModEn is set when SNP enabled

From: Ashish Kalra <ashish.kalra@....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@...ux.microsoft.com>
Closes: https://lore.kernel.org/kvm/68b2d6bf-bce7-47f9-bebb-2652cc923ff9@linux.microsoft.com/
Signed-off-by: Ashish Kalra <ashish.kalra@....com>
Signed-off-by: Michael Roth <michael.roth@....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