summaryrefslogtreecommitdiffstats
path: root/arch/x86/kvm/paging_tmpl.h
diff options
context:
space:
mode:
authorTakuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>2011-05-07 16:31:36 +0900
committerAvi Kivity <avi@redhat.com>2011-05-22 08:47:54 -0400
commit12cb814f3bb35736420cc6bfc9fed7b6a9d3a828 (patch)
tree86371ff3cc2a2e9e08211cd20c464b8efbabb1d6 /arch/x86/kvm/paging_tmpl.h
parent5ce941ee4258b836cf818d2ac159d8cf3ebad648 (diff)
downloadblackbird-op-linux-12cb814f3bb35736420cc6bfc9fed7b6a9d3a828.tar.gz
blackbird-op-linux-12cb814f3bb35736420cc6bfc9fed7b6a9d3a828.zip
KVM: MMU: Clean up gpte reading with copy_from_user()
When we optimized walk_addr_generic() by not using the generic guest memory reader, we replaced copy_from_user() with get_user(): commit e30d2a170506830d5eef5e9d7990c5aedf1b0a51 KVM: MMU: Optimize guest page table walk commit 15e2ac9a43d4d7d08088e404fddf2533a8e7d52e KVM: MMU: Fix 64-bit paging breakage on x86_32 But as Andi pointed out later, copy_from_user() does the same as get_user() as long as we give a constant size to it. So we use copy_from_user() to clean up the code. The only, noticeable, regression introduced by this is 64-bit gpte reading on x86_32 hosts needed for PAE guests. But this can be mitigated by implementing 8-byte get_user() for x86_32, if needed. Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/x86/kvm/paging_tmpl.h')
-rw-r--r--arch/x86/kvm/paging_tmpl.h16
1 files changed, 1 insertions, 15 deletions
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 52450a6b784f..88ca456ccd68 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -115,20 +115,6 @@ static unsigned FNAME(gpte_access)(struct kvm_vcpu *vcpu, pt_element_t gpte)
return access;
}
-static int FNAME(read_gpte)(pt_element_t *pte, pt_element_t __user *ptep_user)
-{
-#if defined(CONFIG_X86_32) && (PTTYPE == 64)
- u32 *p = (u32 *)pte;
- u32 __user *p_user = (u32 __user *)ptep_user;
-
- if (unlikely(get_user(*p, p_user)))
- return -EFAULT;
- return get_user(*(p + 1), p_user + 1);
-#else
- return get_user(*pte, ptep_user);
-#endif
-}
-
/*
* Fetch a guest pte for a guest virtual address
*/
@@ -199,7 +185,7 @@ walk:
}
ptep_user = (pt_element_t __user *)((void *)host_addr + offset);
- if (unlikely(FNAME(read_gpte)(&pte, ptep_user))) {
+ if (unlikely(copy_from_user(&pte, ptep_user, sizeof(pte)))) {
present = false;
break;
}
OpenPOWER on IntegriCloud