diff options
| author | Paolo Bonzini <pbonzini@redhat.com> | 2019-07-19 18:41:10 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-07-31 07:28:57 +0200 |
| commit | 67055806bec952799e6ff5a15605c7c4a75c1c4f (patch) | |
| tree | f765df09f3a7f35846dff89b0615659446b776ca /arch/x86/kvm/vmx.c | |
| parent | e25ec1499721beabd1916e9d8283a65b4d6349bd (diff) | |
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>
Diffstat (limited to 'arch/x86/kvm/vmx.c')
| -rw-r--r-- | arch/x86/kvm/vmx.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 9b2486e8ec00..ae484edcf7a3 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -7694,6 +7694,7 @@ 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) @@ -7705,7 +7706,6 @@ 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; @@ -7891,6 +7891,9 @@ static void copy_shadow_to_vmcs12(struct vcpu_vmx *vmx) const unsigned long *fields = shadow_read_write_fields; const int num_fields = max_shadow_read_write_fields; + if (WARN_ON(!shadow_vmcs)) + return; + preempt_disable(); vmcs_load(shadow_vmcs); @@ -7938,6 +7941,9 @@ 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++) { |