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authorAvi Kivity <avi@qumranet.com>2007-07-23 18:33:14 +0300
committerAvi Kivity <avi@qumranet.com>2007-07-25 14:30:56 +0300
commit7cfa4b0a43286b1da3afa4f5f99d52e65a8f30fc (patch)
tree2ab8a60fa7ed5164fa650452db9af957e07bb235
parent5e58cfe41c7e5902c32bb7f62993d43fb4c48ccf (diff)
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>
-rw-r--r--drivers/kvm/kvm_main.c6
1 files changed, 2 insertions, 4 deletions
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 46efbe70801..a8d8db8e3cc 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -1070,10 +1070,8 @@ static int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
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;
}