KVM: nVMX: Put vmcs12 pages if nested VM-Enter fails due to invalid guest state

Put all vmcs12 pages if KVM synthesizes a nested VM-Exit due to invalid
guest while emulating VMLAUNCH or VMRESUME.  The invalid guest state path
doesn't use nested_vmx_vmexit() as that API is intended to be used if and
only if L2 is active, and the open coded equivalent neglects to put the
vmcs12 pages.  Failure to put the vmcs12 pages leaks any pinned pages
(and/or mappings) if L1 retries VMLAUNCH/VMRESUME.

Note, the !from_vmenter scenario doesn't suffer the same problem, as
vmx_get_nested_state_pages() only gets/pins/maps the vmcs12 pages if L2 is
active, i.e. if a "full" VM-Exit is guaranteed before KVM will retry
getting vmcs12 pages.

Fixes: 96c66e87deee ("KVM/nVMX: Use kvm_vcpu_map when mapping the virtual APIC page")
Fixes: 3278e0492554 ("KVM/nVMX: Use kvm_vcpu_map when mapping the posted interrupt descriptor table")
Fixes: fe1911aa443e ("KVM: nVMX: Use kvm_vcpu_map() to get/pin vmcs12's APIC-access page")
Reported-by: Minh Nguyen <minhnguyen.080505@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index bb0eb40b44483866c22425c25e52235115fb5f11..220d42ebc82e50a90dead11b9d1eca55aa703289 100644 (file)
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -3761,6 +3761,8 @@ vmentry_fail_vmexit:
        if (!from_vmentry)
                return NVMX_VMENTRY_VMEXIT;
 
+       nested_put_vmcs12_pages(vcpu);
+
        load_vmcs12_host_state(vcpu, vmcs12);
        vmcs12->vm_exit_reason = exit_reason.full;
        if (enable_shadow_vmcs || nested_vmx_is_evmptr12_valid(vmx))