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KVM: Change kvm_{read,write}_guest() to use copy_{from,to}_user()

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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>
This commit is contained in:
Izik Eidus 2007-11-11 22:10:22 +02:00 committed by Avi Kivity
parent 539cb6608c
commit e0506bcba5
1 changed files with 14 additions and 24 deletions
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38
drivers/kvm/kvm_main.c
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@ -630,20 +630,15 @@ static int next_segment(unsigned long len, int offset)
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;
r = copy_from_user(data, (void __user *)addr + offset, len);
if (r)
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);
return 0;
}
EXPORT_SYMBOL_GPL(kvm_read_guest_page);
@ -671,21 +666,16 @@ EXPORT_SYMBOL_GPL(kvm_read_guest);
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;
r = copy_to_user((void __user *)addr + offset, data, len);
if (r)
return -EFAULT;
}
page_virt = kmap_atomic(page, KM_USER0);
memcpy(page_virt + offset, data, len);
kunmap_atomic(page_virt, KM_USER0);
mark_page_dirty(kvm, gfn);
kvm_release_page(page);
return 0;
}
EXPORT_SYMBOL_GPL(kvm_write_guest_page);