Commit 7cfa4b0a authored by Avi Kivity's avatar Avi Kivity

Revert "KVM: Avoid useless memory write when possible"

This reverts commit a3c870bd.  While it
does save useless updates, it (probably) defeats the fork detector, causing
a massive performance loss.
Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent 5e58cfe4
...@@ -1070,10 +1070,8 @@ static int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa, ...@@ -1070,10 +1070,8 @@ static int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
return 0; return 0;
mark_page_dirty(vcpu->kvm, gpa >> PAGE_SHIFT); mark_page_dirty(vcpu->kvm, gpa >> PAGE_SHIFT);
virt = kmap_atomic(page, KM_USER0); 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); kvm_mmu_pte_write(vcpu, gpa, virt + offset, val, bytes);
memcpy(virt + offset_in_page(gpa), val, bytes); memcpy(virt + offset_in_page(gpa), val, bytes);
}
kunmap_atomic(virt, KM_USER0); kunmap_atomic(virt, KM_USER0);
return 1; return 1;
} }
......
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