linux-kernel - [tip: x86/urgent] x86/CPU/AMD: Clear virtualized VMLOAD/VMSAVE on Zen4 client

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Message-ID: <173082669399.32228.18413426871343797924.tip-bot2@tip-bot2>
Date: Tue, 05 Nov 2024 17:11:33 -0000
From: "tip-bot2 for Mario Limonciello" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Mario Limonciello <mario.limonciello@....com>,
 "Borislav Petkov (AMD)" <bp@...en8.de>, stable@...r.kernel.org,
 x86@...nel.org, linux-kernel@...r.kernel.org
Subject:
 [tip: x86/urgent] x86/CPU/AMD: Clear virtualized VMLOAD/VMSAVE on Zen4 client

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     a5ca1dc46a6b610dd4627d8b633d6c84f9724ef0
Gitweb:        https://git.kernel.org/tip/a5ca1dc46a6b610dd4627d8b633d6c84f9724ef0
Author:        Mario Limonciello <mario.limonciello@....com>
AuthorDate:    Tue, 05 Nov 2024 10:02:34 -06:00
Committer:     Borislav Petkov (AMD) <bp@...en8.de>
CommitterDate: Tue, 05 Nov 2024 17:48:32 +01:00

x86/CPU/AMD: Clear virtualized VMLOAD/VMSAVE on Zen4 client

A number of Zen4 client SoCs advertise the ability to use virtualized
VMLOAD/VMSAVE, but using these instructions is reported to be a cause
of a random host reboot.

These instructions aren't intended to be advertised on Zen4 client
so clear the capability.

Signed-off-by: Mario Limonciello <mario.limonciello@....com>
Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
Cc: stable@...r.kernel.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=219009
---
 arch/x86/kernel/cpu/amd.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index fab5cae..823f44f 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -924,6 +924,17 @@ static void init_amd_zen4(struct cpuinfo_x86 *c)
 {
 	if (!cpu_has(c, X86_FEATURE_HYPERVISOR))
 		msr_set_bit(MSR_ZEN4_BP_CFG, MSR_ZEN4_BP_CFG_SHARED_BTB_FIX_BIT);
+
+	/*
+	 * These Zen4 SoCs advertise support for virtualized VMLOAD/VMSAVE
+	 * in some BIOS versions but they can lead to random host reboots.
+	 */
+	switch (c->x86_model) {
+	case 0x18 ... 0x1f:
+	case 0x60 ... 0x7f:
+		clear_cpu_cap(c, X86_FEATURE_V_VMSAVE_VMLOAD);
+		break;
+	}
 }
 
 static void init_amd_zen5(struct cpuinfo_x86 *c)