[PATCH 6.1.y] x86/CPU/AMD: Clear virtualized VMLOAD/VMSAVE on Zen4 client

[Artem Dinaburg <artem@trailofbits.com>]

From: Mario Limonciello <mario.limonciello@amd.com>

[ Upstream commit a5ca1dc46a6b610dd4627d8b633d6c84f9724ef0 ]

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@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: stable@vger.kernel.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=219009
Assisted-by: LLM
Signed-off-by: Artem Dinaburg <artem@trailofbits.com>
---
Hi Greg, Sasha, and x86 amd maintainers,

I am working through the small CVE backports still missing from 6.1.y.
This one addresses CVE-2024-53114. It clears virtualized VMLOAD/VMSAVE on
affected Zen 4 client models.

The corresponding 6.6.y backport is already in the 6.6.y stable queue.
The fix is already present in 6.12.y, 6.18.y, and 7.2.y, but not
in 6.1.y.
The code change is identical to upstream.

Could you please queue it for 6.1.y?

CVE: CVE-2024-53114
Upstream: a5ca1dc46a6b610dd4627d8b633d6c84f9724ef0

AI assistance: An LLM helped identify, adapt, and validate this backport; I
reviewed the resulting code and validation evidence.

Thanks,
Artem Dinaburg

 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 a61606a614bd71..8d9c067992e5f5 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -1161,6 +1161,17 @@ static void init_amd_zen3(struct cpuinfo_x86 *c)
 static void init_amd_zen4(struct cpuinfo_x86 *c)
 {
 	init_amd_zen_common();
+
+	/*
+	 * 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(struct cpuinfo_x86 *c)
-- 
2.39.5