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

[Paolo Bonzini]

From: Sean Christopherson <seanjc@xxxxxxxxxx>

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@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
 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 bb0eb40b4448..220d42ebc82e 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -3761,6 +3761,8 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,
 	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))
-- 
2.54.0