3.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Marcelo Tosatti <mtosa...@redhat.com>

commit 989c6b34f6a9480e397b170cc62237e89bf4fdb9 upstream.

It is possible for __direct_map to be called on invalid root_hpa
(-1), two examples:

1) try_async_pf -> can_do_async_pf
    -> vmx_interrupt_allowed -> nested_vmx_vmexit
2) vmx_handle_exit -> vmx_interrupt_allowed -> nested_vmx_vmexit

Then to load_vmcs12_host_state and kvm_mmu_reset_context.

Check for this possibility, let fault exception be regenerated.

BZ: https://bugzilla.redhat.com/show_bug.cgi?id=924916

Signed-off-by: Marcelo Tosatti <mtosa...@redhat.com>
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
Cc: Josh Boyer <jwbo...@fedoraproject.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 arch/x86/kvm/mmu.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2585,6 +2585,9 @@ static int __direct_map(struct kvm_vcpu
        int emulate = 0;
        gfn_t pseudo_gfn;
 
+       if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
+               return 0;
+
        for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) {
                if (iterator.level == level) {
                        mmu_set_spte(vcpu, iterator.sptep, ACC_ALL,


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