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| author |   Paolo Bonzini <pbonzini@redhat.com> | 2019-07-19 18:41:10 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2019-07-20 09:00:47 +0200 |
| commit | 88dddc11a8d6b09201b4db9d255b3394d9bc9e57 (patch) | |
| tree | 286cb8c531c862040deb05e5746f65dacf1c9150 /arch/x86 | |
| parent | KVM: VMX: dump VMCS on failed entry (diff) | |
| download | linux-dev-88dddc11a8d6b09201b4db9d255b3394d9bc9e57.tar.xz linux-dev-88dddc11a8d6b09201b4db9d255b3394d9bc9e57.zip | |
KVM: nVMX: do not use dangling shadow VMCS after guest reset
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>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/vmx/nested.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 4f23e34f628b..0f1378789bd0 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -194,6 +194,7 @@ static void vmx_disable_shadow_vmcs(struct vcpu_vmx *vmx) { secondary_exec_controls_clearbit(vmx, SECONDARY_EXEC_SHADOW_VMCS); vmcs_write64(VMCS_LINK_POINTER, -1ull); + vmx->nested.need_vmcs12_to_shadow_sync = false; } static inline void nested_release_evmcs(struct kvm_vcpu *vcpu) @@ -1341,6 +1342,9 @@ static void copy_shadow_to_vmcs12(struct vcpu_vmx *vmx) unsigned long val; int i; + if (WARN_ON(!shadow_vmcs)) + return; + preempt_disable(); vmcs_load(shadow_vmcs); @@ -1373,6 +1377,9 @@ static void copy_vmcs12_to_shadow(struct vcpu_vmx *vmx) unsigned long val; int i, q; + if (WARN_ON(!shadow_vmcs)) + return; + vmcs_load(shadow_vmcs); for (q = 0; q < ARRAY_SIZE(fields); q++) { @@ -4436,7 +4443,6 @@ static inline void nested_release_vmcs12(struct kvm_vcpu *vcpu) /* copy to memory all shadowed fields in case they were modified */ copy_shadow_to_vmcs12(vmx); - vmx->nested.need_vmcs12_to_shadow_sync = false; vmx_disable_shadow_vmcs(vmx); } vmx->nested.posted_intr_nv = -1; |