Revert "KVM: Avoid useless memory write when possible"
This reverts commit a3c870bdce4d34332ebdba7eb9969592c4c6b243. While it
does save useless updates, it (probably) defeats the fork detector, causing
a massive performance loss.
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 46efbe7..a8d8db8 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -1070,10 +1070,8 @@
return 0;
mark_page_dirty(vcpu->kvm, gpa >> PAGE_SHIFT);
virt = kmap_atomic(page, KM_USER0);
- if (memcmp(virt + offset_in_page(gpa), val, bytes)) {
- kvm_mmu_pte_write(vcpu, gpa, virt + offset, val, bytes);
- memcpy(virt + offset_in_page(gpa), val, bytes);
- }
+ kvm_mmu_pte_write(vcpu, gpa, virt + offset, val, bytes);
+ memcpy(virt + offset_in_page(gpa), val, bytes);
kunmap_atomic(virt, KM_USER0);
return 1;
}