KVM: Change kvm_{read,write}_guest() to use copy_{from,to}_user()
This changes kvm_write_guest_page/kvm_read_guest_page to use
copy_to_user/read_from_user, as a result we get better speed
and better dirty bit tracking.
Signed-off-by: Izik Eidus <izike@qumranet.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 04544ae..d68901b 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -630,20 +630,15 @@
int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset,
int len)
{
- void *page_virt;
- struct page *page;
+ int r;
+ unsigned long addr;
- page = gfn_to_page(kvm, gfn);
- if (is_error_page(page)) {
- kvm_release_page(page);
+ addr = gfn_to_hva(kvm, gfn);
+ if (kvm_is_error_hva(addr))
return -EFAULT;
- }
- page_virt = kmap_atomic(page, KM_USER0);
-
- memcpy(data, page_virt + offset, len);
-
- kunmap_atomic(page_virt, KM_USER0);
- kvm_release_page(page);
+ r = copy_from_user(data, (void __user *)addr + offset, len);
+ if (r)
+ return -EFAULT;
return 0;
}
EXPORT_SYMBOL_GPL(kvm_read_guest_page);
@@ -671,21 +666,16 @@
int kvm_write_guest_page(struct kvm *kvm, gfn_t gfn, const void *data,
int offset, int len)
{
- void *page_virt;
- struct page *page;
+ int r;
+ unsigned long addr;
- page = gfn_to_page(kvm, gfn);
- if (is_error_page(page)) {
- kvm_release_page(page);
+ addr = gfn_to_hva(kvm, gfn);
+ if (kvm_is_error_hva(addr))
return -EFAULT;
- }
- page_virt = kmap_atomic(page, KM_USER0);
-
- memcpy(page_virt + offset, data, len);
-
- kunmap_atomic(page_virt, KM_USER0);
+ r = copy_to_user((void __user *)addr + offset, data, len);
+ if (r)
+ return -EFAULT;
mark_page_dirty(kvm, gfn);
- kvm_release_page(page);
return 0;
}
EXPORT_SYMBOL_GPL(kvm_write_guest_page);