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| author | Paolo Bonzini <pbonzini@redhat.com> | 2019-07-19 18:41:10 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-07-28 08:28:37 +0200 |
| commit | 93e7720cc238bfb9784bb2b8d340b4595e7891b1 (patch) | |
| tree | bd5dd1a059e3c329907de01757b936a3969db3f1 | |
| parent | 7f1f86276515f6816a98f6ca3ef99c827d54642f (diff) | |
| download | linux-stable-93e7720cc238bfb9784bb2b8d340b4595e7891b1.tar.gz linux-stable-93e7720cc238bfb9784bb2b8d340b4595e7891b1.tar.bz2 linux-stable-93e7720cc238bfb9784bb2b8d340b4595e7891b1.zip | |
KVM: nVMX: do not use dangling shadow VMCS after guest reset
commit 88dddc11a8d6b09201b4db9d255b3394d9bc9e57 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 f83e79a4d0b2..d36565dcc767 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -184,6 +184,7 @@ 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.need_vmcs12_sync = false; } static inline void nested_release_evmcs(struct kvm_vcpu *vcpu) @@ -1328,6 +1329,9 @@ 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); @@ -1366,6 +1370,9 @@ 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++) { @@ -4336,7 +4343,6 @@ 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_sync = false; vmx_disable_shadow_vmcs(vmx); } vmx->nested.posted_intr_nv = -1; |