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Message-ID: <69fd07b45b63fde44a39dbae045343037ccb39f9.1722368407.git.thomas.lendacky@amd.com>
Date: Tue, 30 Jul 2024 14:40:03 -0500
From: Tom Lendacky <thomas.lendacky@....com>
To: <linux-kernel@...r.kernel.org>, <x86@...nel.org>
CC: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>,
Michael Roth <michael.roth@....com>, Ashish Kalra <ashish.kalra@....com>
Subject: [PATCH v2 3/7] x86/sev: Require the RMPREAD instruction after Fam19h
Limit usage of the non-architectural RMP format to Fam19h processors.
The RMPREAD instruction, with its architecture defined output, is
available, and should be used, for RMP access beyond Fam19h.
Signed-off-by: Tom Lendacky <thomas.lendacky@....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 be5889bded49..0b39249640ee 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -358,7 +358,8 @@ static void bsp_determine_snp(struct cpuinfo_x86 *c)
* for which the RMP table entry format is currently defined for.
*/
if (!cpu_has(c, X86_FEATURE_HYPERVISOR) &&
- c->x86 >= 0x19 && snp_probe_rmptable_info()) {
+ (c->x86 == 0x19 || cpu_feature_enabled(X86_FEATURE_RMPREAD)) &&
+ snp_probe_rmptable_info()) {
cc_platform_set(CC_ATTR_HOST_SEV_SNP);
} else {
setup_clear_cpu_cap(X86_FEATURE_SEV_SNP);
--
2.43.2
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