aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorPaolo Bonzini <pbonzini@redhat.com>2019-07-19 18:41:10 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2019-07-20 09:00:47 +0200
commit88dddc11a8d6b09201b4db9d255b3394d9bc9e57 (patch)
tree286cb8c531c862040deb05e5746f65dacf1c9150
parent3b20e03a1066ab2056711166c1b41d421d1ff7b7 (diff)
downloadlinux-stericsson-88dddc11a8d6b09201b4db9d255b3394d9bc9e57.tar.gz
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>
-rw-r--r--arch/x86/kvm/vmx/nested.c8
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;