* [PATCH 1/1] KVM: x86/mmu: Set memory encryption "value", not "mask", in shadow PDPTRs
@ 2022-06-08 1:20 Yuan Yao
2022-06-08 12:37 ` Paolo Bonzini
0 siblings, 1 reply; 3+ messages in thread
From: Yuan Yao @ 2022-06-08 1:20 UTC (permalink / raw)
To: kvm, linux-kernel
Cc: Paolo Bonzini, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li,
Jim Mattson, Joerg Roedel, Kai Huang, Yuan Yao
Assign shadow_me_value, not shadow_me_mask, to PAE root entries,
a.k.a. shadow PDPTRs, when host memory encryption is supported. The
"mask" is the set of all possible memory encryption bits, e.g. MKTME
KeyIDs, whereas "value" holds the actual value that needs to be
stuffed into host page tables.
Using shadow_me_mask results in a failed VM-Entry due to setting
reserved PA bits in the PDPTRs, and ultimately causes an OOPS due to
physical addresses with non-zero MKTME bits sending to_shadow_page()
into the weeds:
set kvm_intel.dump_invalid_vmcs=1 to dump internal KVM state.
BUG: unable to handle page fault for address: ffd43f00063049e8
PGD 86dfd8067 P4D 0
Oops: 0000 [#1] PREEMPT SMP
RIP: 0010:mmu_free_root_page+0x3c/0x90 [kvm]
kvm_mmu_free_roots+0xd1/0x200 [kvm]
__kvm_mmu_unload+0x29/0x70 [kvm]
kvm_mmu_unload+0x13/0x20 [kvm]
kvm_arch_destroy_vm+0x8a/0x190 [kvm]
kvm_put_kvm+0x197/0x2d0 [kvm]
kvm_vm_release+0x21/0x30 [kvm]
__fput+0x8e/0x260
____fput+0xe/0x10
task_work_run+0x6f/0xb0
do_exit+0x327/0xa90
do_group_exit+0x35/0xa0
get_signal+0x911/0x930
arch_do_signal_or_restart+0x37/0x720
exit_to_user_mode_prepare+0xb2/0x140
syscall_exit_to_user_mode+0x16/0x30
do_syscall_64+0x4e/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
Fixes: e54f1ff244ac ("KVM: x86/mmu: Add shadow_me_value and repurpose shadow_me_mask")
Signed-off-by: Yuan Yao <yuan.yao@intel.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
---
arch/x86/kvm/mmu/mmu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index efe5a3dca1e0..6bd144f1e60c 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3411,7 +3411,7 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
root = mmu_alloc_root(vcpu, i << (30 - PAGE_SHIFT),
i << 30, PT32_ROOT_LEVEL, true);
mmu->pae_root[i] = root | PT_PRESENT_MASK |
- shadow_me_mask;
+ shadow_me_value;
}
mmu->root.hpa = __pa(mmu->pae_root);
} else {
--
2.27.0
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH 1/1] KVM: x86/mmu: Set memory encryption "value", not "mask", in shadow PDPTRs
2022-06-08 1:20 [PATCH 1/1] KVM: x86/mmu: Set memory encryption "value", not "mask", in shadow PDPTRs Yuan Yao
@ 2022-06-08 12:37 ` Paolo Bonzini
2022-06-08 22:53 ` Yuan Yao
0 siblings, 1 reply; 3+ messages in thread
From: Paolo Bonzini @ 2022-06-08 12:37 UTC (permalink / raw)
To: Yuan Yao, kvm, linux-kernel
Cc: Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li, Jim Mattson,
Joerg Roedel, Kai Huang, Yuan Yao
On 6/8/22 03:20, Yuan Yao wrote:
> Assign shadow_me_value, not shadow_me_mask, to PAE root entries,
> a.k.a. shadow PDPTRs, when host memory encryption is supported. The
> "mask" is the set of all possible memory encryption bits, e.g. MKTME
> KeyIDs, whereas "value" holds the actual value that needs to be
> stuffed into host page tables.
>
> Using shadow_me_mask results in a failed VM-Entry due to setting
> reserved PA bits in the PDPTRs, and ultimately causes an OOPS due to
> physical addresses with non-zero MKTME bits sending to_shadow_page()
> into the weeds:
>
> set kvm_intel.dump_invalid_vmcs=1 to dump internal KVM state.
> BUG: unable to handle page fault for address: ffd43f00063049e8
> PGD 86dfd8067 P4D 0
> Oops: 0000 [#1] PREEMPT SMP
> RIP: 0010:mmu_free_root_page+0x3c/0x90 [kvm]
> kvm_mmu_free_roots+0xd1/0x200 [kvm]
> __kvm_mmu_unload+0x29/0x70 [kvm]
> kvm_mmu_unload+0x13/0x20 [kvm]
> kvm_arch_destroy_vm+0x8a/0x190 [kvm]
> kvm_put_kvm+0x197/0x2d0 [kvm]
> kvm_vm_release+0x21/0x30 [kvm]
> __fput+0x8e/0x260
> ____fput+0xe/0x10
> task_work_run+0x6f/0xb0
> do_exit+0x327/0xa90
> do_group_exit+0x35/0xa0
> get_signal+0x911/0x930
> arch_do_signal_or_restart+0x37/0x720
> exit_to_user_mode_prepare+0xb2/0x140
> syscall_exit_to_user_mode+0x16/0x30
> do_syscall_64+0x4e/0x90
> entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> Fixes: e54f1ff244ac ("KVM: x86/mmu: Add shadow_me_value and repurpose shadow_me_mask")
> Signed-off-by: Yuan Yao <yuan.yao@intel.com>
> Reviewed-by: Kai Huang <kai.huang@intel.com>
> ---
> arch/x86/kvm/mmu/mmu.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index efe5a3dca1e0..6bd144f1e60c 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -3411,7 +3411,7 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
> root = mmu_alloc_root(vcpu, i << (30 - PAGE_SHIFT),
> i << 30, PT32_ROOT_LEVEL, true);
> mmu->pae_root[i] = root | PT_PRESENT_MASK |
> - shadow_me_mask;
> + shadow_me_value;
> }
> mmu->root.hpa = __pa(mmu->pae_root);
> } else {
Queued, thanks.
Paolo
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH 1/1] KVM: x86/mmu: Set memory encryption "value", not "mask", in shadow PDPTRs
2022-06-08 12:37 ` Paolo Bonzini
@ 2022-06-08 22:53 ` Yuan Yao
0 siblings, 0 replies; 3+ messages in thread
From: Yuan Yao @ 2022-06-08 22:53 UTC (permalink / raw)
To: Paolo Bonzini
Cc: Yuan Yao, kvm, linux-kernel, Sean Christopherson,
Vitaly Kuznetsov, Wanpeng Li, Jim Mattson, Joerg Roedel,
Kai Huang
On Wed, Jun 08, 2022 at 02:37:27PM +0200, Paolo Bonzini wrote:
> On 6/8/22 03:20, Yuan Yao wrote:
> > Assign shadow_me_value, not shadow_me_mask, to PAE root entries,
> > a.k.a. shadow PDPTRs, when host memory encryption is supported. The
> > "mask" is the set of all possible memory encryption bits, e.g. MKTME
> > KeyIDs, whereas "value" holds the actual value that needs to be
> > stuffed into host page tables.
> >
> > Using shadow_me_mask results in a failed VM-Entry due to setting
> > reserved PA bits in the PDPTRs, and ultimately causes an OOPS due to
> > physical addresses with non-zero MKTME bits sending to_shadow_page()
> > into the weeds:
> >
> > set kvm_intel.dump_invalid_vmcs=1 to dump internal KVM state.
> > BUG: unable to handle page fault for address: ffd43f00063049e8
> > PGD 86dfd8067 P4D 0
> > Oops: 0000 [#1] PREEMPT SMP
> > RIP: 0010:mmu_free_root_page+0x3c/0x90 [kvm]
> > kvm_mmu_free_roots+0xd1/0x200 [kvm]
> > __kvm_mmu_unload+0x29/0x70 [kvm]
> > kvm_mmu_unload+0x13/0x20 [kvm]
> > kvm_arch_destroy_vm+0x8a/0x190 [kvm]
> > kvm_put_kvm+0x197/0x2d0 [kvm]
> > kvm_vm_release+0x21/0x30 [kvm]
> > __fput+0x8e/0x260
> > ____fput+0xe/0x10
> > task_work_run+0x6f/0xb0
> > do_exit+0x327/0xa90
> > do_group_exit+0x35/0xa0
> > get_signal+0x911/0x930
> > arch_do_signal_or_restart+0x37/0x720
> > exit_to_user_mode_prepare+0xb2/0x140
> > syscall_exit_to_user_mode+0x16/0x30
> > do_syscall_64+0x4e/0x90
> > entry_SYSCALL_64_after_hwframe+0x44/0xae
> >
> > Fixes: e54f1ff244ac ("KVM: x86/mmu: Add shadow_me_value and repurpose shadow_me_mask")
> > Signed-off-by: Yuan Yao <yuan.yao@intel.com>
> > Reviewed-by: Kai Huang <kai.huang@intel.com>
> > ---
> > arch/x86/kvm/mmu/mmu.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> > index efe5a3dca1e0..6bd144f1e60c 100644
> > --- a/arch/x86/kvm/mmu/mmu.c
> > +++ b/arch/x86/kvm/mmu/mmu.c
> > @@ -3411,7 +3411,7 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
> > root = mmu_alloc_root(vcpu, i << (30 - PAGE_SHIFT),
> > i << 30, PT32_ROOT_LEVEL, true);
> > mmu->pae_root[i] = root | PT_PRESENT_MASK |
> > - shadow_me_mask;
> > + shadow_me_value;
> > }
> > mmu->root.hpa = __pa(mmu->pae_root);
> > } else {
>
> Queued, thanks.
>
> Paolo
Thanks Paolo, and Thanks again to Sean Christopherson
<seanjc@google.com>'s nice help for patch subject/format on this patch
(was [PATCH 1/1] KVM: MMU: Fix VM entry failure and OOPS for shdaow
page table).
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2022-06-08 22:53 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2022-06-08 1:20 [PATCH 1/1] KVM: x86/mmu: Set memory encryption "value", not "mask", in shadow PDPTRs Yuan Yao
2022-06-08 12:37 ` Paolo Bonzini
2022-06-08 22:53 ` Yuan Yao
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