KVM: Fix mmu_reload() clash with nested vmx event injection

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Currently the inject_pending_event() call during guest entry happens after
kvm_mmu_reload().  This is for historical reasons - we used to
inject_pending_event() in atomic context, while kvm_mmu_reload() needs task
context.

A problem is that nested vmx can cause the mmu context to be reset, if event
injection is intercepted and causes a #VMEXIT instead (the #VMEXIT resets
CR0/CR3/CR4).  If this happens, we end up with invalid root_hpa, and since
kvm_mmu_reload() has already run, no one will fix it and we end up entering
the guest this way.

Fix by reordering event injection to be before kvm_mmu_reload().  Use
->cancel_injection() to undo if kvm_mmu_reload() fails.

https://bugzilla.kernel.org/show_bug.cgi?id=42980

Reported-by: Luke-Jr <luke-jr+linuxbugs@utopios.org>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

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Avi Kivity 2012-05-14 18:07:56 +03:00 • committed by Marcelo Tosatti

parent c142786c62

commit d8368af8b4

1 changed files with 6 additions and 4 deletions

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arch/x86/kvm/x86.c

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