> On 21 Jul 2019, at 14:52, Jan Kiszka <jan.kiszka@xxxxxx> wrote: > > From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> > > Letting this pend may cause nested_get_vmcs12_pages to run against an > invalid state, corrupting the effective vmcs of L1. > > This was triggerable in QEMU after a guest corruption in L2, followed by > a L1 reset. > > Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> Good catch. Reviewed-by: Liran Alon <liran.alon@xxxxxxxxxx> This would have been more easily diagnosed in case free_nested() would NULL cached_vmcs12 and cached_shadow_vmcs12 after kfree() and add to get_vmcs12() & get_shadow_vmcs12() a relevant BUG_ON() call. I would submit such a patch separately. -Liran > --- > > And another gremlin. I'm afraid there is at least one more because > vmport access from L2 is still failing in QEMU. This is just another > fallout from that. At least the host seems stable now. > > arch/x86/kvm/vmx/nested.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c > index 0f1378789bd0..4cdab4b4eff1 100644 > --- a/arch/x86/kvm/vmx/nested.c > +++ b/arch/x86/kvm/vmx/nested.c > @@ -220,6 +220,8 @@ static void free_nested(struct kvm_vcpu *vcpu) > if (!vmx->nested.vmxon && !vmx->nested.smm.vmxon) > return; > > + kvm_clear_request(KVM_REQ_GET_VMCS12_PAGES, vcpu); > + > vmx->nested.vmxon = false; > vmx->nested.smm.vmxon = false; > free_vpid(vmx->nested.vpid02); > -- > 2.16.4
