[PATCH 6.6.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 6.6.y.
This one addresses CVE-2024-53114. It clears virtualized VMLOAD/VMSAVE on
affected Zen 4 client models.

The fix is already present in 6.12.y, 6.18.y, and 7.2.y, but not in 6.6.y.
This fix also affects 6.1.y, which will need a separate backport; this
submission contains only the 6.6.y patch.
The code change is identical to upstream.

Could you please queue it for 6.6.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 a2313fa8a0729e..955da4c2385fa0 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -1196,6 +1196,17 @@ 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_zen5(struct cpuinfo_x86 *c)
-- 
2.39.5