Messages in this thread | | | Subject | Re: [PATCH] KVM: nVMX: Use vmx_need_pf_intercept() when deciding if L0 wants a #PF | From | Paolo Bonzini <> | Date | Thu, 12 Aug 2021 18:18:53 +0200 |
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On 12/08/21 06:56, Sean Christopherson wrote: > Use vmx_need_pf_intercept() when determining if L0 wants to handle a #PF > in L2 or if the VM-Exit should be forwarded to L1. The current logic fails > to account for the case where #PF is intercepted to handle > guest.MAXPHYADDR < host.MAXPHYADDR and ends up reflecting all #PFs into > L1. At best, L1 will complain and inject the #PF back into L2. At > worst, L1 will eat the unexpected fault and cause L2 to hang on infinite > page faults. > > Note, while the bug was technically introduced by the commit that added > support for the MAXPHYADDR madness, the shame is all on commit > a0c134347baf ("KVM: VMX: introduce vmx_need_pf_intercept"). > > Fixes: 1dbf5d68af6f ("KVM: VMX: Add guest physical address check in EPT violation and misconfig") > Cc: stable@vger.kernel.org > Cc: Peter Shier <pshier@google.com> > Cc: Oliver Upton <oupton@google.com> > Cc: Jim Mattson <jmattson@google.com> > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > arch/x86/kvm/vmx/nested.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c > index bc6327950657..8bcbe57b560f 100644 > --- a/arch/x86/kvm/vmx/nested.c > +++ b/arch/x86/kvm/vmx/nested.c > @@ -5830,7 +5830,8 @@ static bool nested_vmx_l0_wants_exit(struct kvm_vcpu *vcpu, > if (is_nmi(intr_info)) > return true; > else if (is_page_fault(intr_info)) > - return vcpu->arch.apf.host_apf_flags || !enable_ept; > + return vcpu->arch.apf.host_apf_flags || > + vmx_need_pf_intercept(vcpu); > else if (is_debug(intr_info) && > vcpu->guest_debug & > (KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP)) >
Queued, thanks.
Paolo
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