KVM: MMU: fast invalidate all mmio sptes
This patch tries to introduce a very simple and scale way to invalidate
all mmio sptes - it need not walk any shadow pages and hold mmu-lock
KVM maintains a global mmio valid generation-number which is stored in
kvm->memslots.generation and every mmio spte stores the current global
generation-number into his available bits when it is created
When KVM need zap all mmio sptes, it just simply increase the global
generation-number. When guests do mmio access, KVM intercepts a MMIO #PF
then it walks the shadow page table and get the mmio spte. If the
generation-number on the spte does not equal the global generation-number,
it will go to the normal #PF handler to update the mmio spte
Since 19 bits are used to store generation-number on mmio spte, we zap all
mmio sptes when the number is round
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 85c8d51..f4a5b3f 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -5369,6 +5369,10 @@
if (likely(ret == RET_MMIO_PF_EMULATE))
return x86_emulate_instruction(vcpu, gpa, 0, NULL, 0) ==
EMULATE_DONE;
+
+ if (unlikely(ret == RET_MMIO_PF_INVALID))
+ return kvm_mmu_page_fault(vcpu, gpa, 0, NULL, 0);
+
if (unlikely(ret == RET_MMIO_PF_RETRY))
return 1;