From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: stable@vger.kernel.org
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>
Subject: [PATCH stable-4.19 1/2] KVM: nVMX: do not use dangling shadow VMCS after guest reset
Date: Thu, 25 Jul 2019 12:46:44 +0200 [thread overview]
Message-ID: <20190725104645.30642-2-vkuznets@redhat.com> (raw)
In-Reply-To: <20190725104645.30642-1-vkuznets@redhat.com>
From: Paolo Bonzini <pbonzini@redhat.com>
[ Upstream commit 88dddc11a8d6b09201b4db9d255b3394d9bc9e57 ]
If a KVM guest is reset while running a nested guest, free_nested will
disable the shadow VMCS execution control in the vmcs01. However,
on the next KVM_RUN vmx_vcpu_run would nevertheless try to sync
the VMCS12 to the shadow VMCS which has since been freed.
This causes a vmptrld of a NULL pointer on my machime, but Jan reports
the host to hang altogether. Let's see how much this trivial patch fixes.
Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Liran Alon <liran.alon@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/vmx.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 73d6d585dd66..880bc36a0d5d 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8457,6 +8457,7 @@ static void vmx_disable_shadow_vmcs(struct vcpu_vmx *vmx)
{
vmcs_clear_bits(SECONDARY_VM_EXEC_CONTROL, SECONDARY_EXEC_SHADOW_VMCS);
vmcs_write64(VMCS_LINK_POINTER, -1ull);
+ vmx->nested.sync_shadow_vmcs = false;
}
static inline void nested_release_vmcs12(struct vcpu_vmx *vmx)
@@ -8468,7 +8469,6 @@ static inline void nested_release_vmcs12(struct vcpu_vmx *vmx)
/* copy to memory all shadowed fields in case
they were modified */
copy_shadow_to_vmcs12(vmx);
- vmx->nested.sync_shadow_vmcs = false;
vmx_disable_shadow_vmcs(vmx);
}
vmx->nested.posted_intr_nv = -1;
@@ -8668,6 +8668,9 @@ static void copy_shadow_to_vmcs12(struct vcpu_vmx *vmx)
u64 field_value;
struct vmcs *shadow_vmcs = vmx->vmcs01.shadow_vmcs;
+ if (WARN_ON(!shadow_vmcs))
+ return;
+
preempt_disable();
vmcs_load(shadow_vmcs);
@@ -8706,6 +8709,9 @@ static void copy_vmcs12_to_shadow(struct vcpu_vmx *vmx)
u64 field_value = 0;
struct vmcs *shadow_vmcs = vmx->vmcs01.shadow_vmcs;
+ if (WARN_ON(!shadow_vmcs))
+ return;
+
vmcs_load(shadow_vmcs);
for (q = 0; q < ARRAY_SIZE(fields); q++) {
--
2.20.1
next prev parent reply other threads:[~2019-07-25 10:47 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-25 10:46 [PATCH stable-4.19 0/2] KVM: nVMX: guest reset fixes Vitaly Kuznetsov
2019-07-25 10:46 ` Vitaly Kuznetsov [this message]
2019-07-29 8:58 ` [PATCH stable-4.19 1/2] KVM: nVMX: do not use dangling shadow VMCS after guest reset Jack Wang
2019-07-29 9:10 ` Paolo Bonzini
2019-07-29 9:29 ` Jack Wang
2019-07-29 9:30 ` Paolo Bonzini
2019-07-29 15:31 ` Greg Kroah-Hartman
2019-07-25 10:46 ` [PATCH stable-4.19 2/2] KVM: nVMX: Clear pending KVM_REQ_GET_VMCS12_PAGES when leaving nested Vitaly Kuznetsov
2019-07-25 11:24 ` [PATCH stable-4.19 0/2] KVM: nVMX: guest reset fixes Paolo Bonzini
2019-07-26 13:48 ` Greg KH
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