This is a note to let you know that I've just added the patch titled
KVM: x86/mmu: Treat NX as a valid SPTE bit for NPT
to the 5.19-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-mmu-treat-nx-as-a-valid-spte-bit-for-npt.patch
and it can be found in the queue-5.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 1d4354d553be3fc86438d397274ddf854202ea95
Author: Sean Christopherson <seanjc@xxxxxxxxxx>
Date: Sat Jul 23 01:30:29 2022 +0000
KVM: x86/mmu: Treat NX as a valid SPTE bit for NPT
[ Upstream commit 6c6ab524cfae0799e55c82b2c1d61f1af0156f8d ]
Treat the NX bit as valid when using NPT, as KVM will set the NX bit when
the NX huge page mitigation is enabled (mindblowing) and trigger the WARN
that fires on reserved SPTE bits being set.
KVM has required NX support for SVM since commit b26a71a1a5b9 ("KVM: SVM:
Refuse to load kvm_amd if NX support is not available") for exactly this
reason, but apparently it never occurred to anyone to actually test NPT
with the mitigation enabled.
------------[ cut here ]------------
spte = 0x800000018a600ee7, level = 2, rsvd bits = 0x800f0000001fe000
WARNING: CPU: 152 PID: 15966 at arch/x86/kvm/mmu/spte.c:215 make_spte+0x327/0x340 [kvm]
Hardware name: Google, Inc. Arcadia_IT_80/Arcadia_IT_80, BIOS 10.48.0 01/27/2022
RIP: 0010:make_spte+0x327/0x340 [kvm]
Call Trace:
<TASK>
tdp_mmu_map_handle_target_level+0xc3/0x230 [kvm]
kvm_tdp_mmu_map+0x343/0x3b0 [kvm]
direct_page_fault+0x1ae/0x2a0 [kvm]
kvm_tdp_page_fault+0x7d/0x90 [kvm]
kvm_mmu_page_fault+0xfb/0x2e0 [kvm]
npf_interception+0x55/0x90 [kvm_amd]
svm_invoke_exit_handler+0x31/0xf0 [kvm_amd]
svm_handle_exit+0xf6/0x1d0 [kvm_amd]
vcpu_enter_guest+0xb6d/0xee0 [kvm]
? kvm_pmu_trigger_event+0x6d/0x230 [kvm]
vcpu_run+0x65/0x2c0 [kvm]
kvm_arch_vcpu_ioctl_run+0x355/0x610 [kvm]
kvm_vcpu_ioctl+0x551/0x610 [kvm]
__se_sys_ioctl+0x77/0xc0
__x64_sys_ioctl+0x1d/0x20
do_syscall_64+0x44/0xa0
entry_SYSCALL_64_after_hwframe+0x46/0xb0
</TASK>
---[ end trace 0000000000000000 ]---
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Message-Id: <20220723013029.1753623-1-seanjc@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 17252f39bd7c..a1d17a826807 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4567,7 +4567,7 @@ reset_tdp_shadow_zero_bits_mask(struct kvm_mmu *context)
if (boot_cpu_is_amd())
__reset_rsvds_bits_mask(shadow_zero_check, reserved_hpa_bits(),
- context->root_role.level, false,
+ context->root_role.level, true,
boot_cpu_has(X86_FEATURE_GBPAGES),
false, true);
else
