This is a note to let you know that I've just added the patch titled
KVM: x86: Mask off reserved bits in CPUID.80000008H
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-x86-mask-off-reserved-bits-in-cpuid.80000008h.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 7030d8530e533844e2f4b0e7476498afcd324634 Mon Sep 17 00:00:00 2001
From: Jim Mattson <jmattson@xxxxxxxxxx>
Date: Thu, 29 Sep 2022 15:52:00 -0700
Subject: KVM: x86: Mask off reserved bits in CPUID.80000008H
From: Jim Mattson <jmattson@xxxxxxxxxx>
commit 7030d8530e533844e2f4b0e7476498afcd324634 upstream.
KVM_GET_SUPPORTED_CPUID should only enumerate features that KVM
actually supports. The following ranges of CPUID.80000008H are reserved
and should be masked off:
ECX[31:18]
ECX[11:8]
In addition, the PerfTscSize field at ECX[17:16] should also be zero
because KVM does not set the PERFTSC bit at CPUID.80000001H.ECX[27].
Fixes: 24c82e576b78 ("KVM: Sanitize cpuid")
Signed-off-by: Jim Mattson <jmattson@xxxxxxxxxx>
Message-Id: <20220929225203.2234702-3-jmattson@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/cpuid.c | 1 +
1 file changed, 1 insertion(+)
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -937,6 +937,7 @@ static inline int __do_cpuid_func(struct
g_phys_as = phys_as;
entry->eax = g_phys_as | (virt_as << 8);
+ entry->ecx &= ~(GENMASK(31, 16) | GENMASK(11, 8));
entry->edx = 0;
cpuid_entry_override(entry, CPUID_8000_0008_EBX);
break;
Patches currently in stable-queue which might be from jmattson@xxxxxxxxxx are
queue-5.15/kvm-x86-mask-off-reserved-bits-in-cpuid.80000008h.patch
queue-5.15/kvm-x86-mask-off-reserved-bits-in-cpuid.80000006h.patch
queue-5.15/kvm-x86-mask-off-reserved-bits-in-cpuid.80000001h.patch
queue-5.15/kvm-x86-mask-off-reserved-bits-in-cpuid.8000001ah.patch
queue-5.15/kvm-x86-mask-off-reserved-bits-in-cpuid.8000001fh.patch
