[PATCH] KVM: MMU: Page table write flood protection
In fork() (or when we protect a page that is no longer a page table), we can
experience floods of writes to a page, which have to be emulated. This is
expensive.
So, if we detect such a flood, zap the page so subsequent writes can proceed
natively.
Signed-off-by: Avi Kivity <avi@qumranet.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index 6e4daf4..201b273 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -238,6 +238,9 @@
struct kvm_mmu_page page_header_buf[KVM_NUM_MMU_PAGES];
struct kvm_mmu mmu;
+ gfn_t last_pt_write_gfn;
+ int last_pt_write_count;
+
struct kvm_guest_debug guest_debug;
char fx_buf[FX_BUF_SIZE];