[PATCH] KVM: MMU: Perform access checks in walk_addr()

Check pte permission bits in walk_addr(), instead of scattering the checks all
over the code.  This has the following benefits:

1. We no longer set the accessed bit for accessed which fail permission checks.
2. Setting the accessed bit is simplified.
3. Under some circumstances, we used to pretend a page fault was fixed when
   it would actually fail the access checks.  This caused an unnecessary
   vmexit.
4. The error code for guest page faults is now correct.

The fix helps netbsd further along booting, and allows kvm to pass the new mmu
testsuite.

Signed-off-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 10 deletions

diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index c6f972914f08..a05d0609d918 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -992,16 +992,6 @@ static inline int fix_read_pf(u64 *shadow_ent)
         return 0;
 }
 
-static int may_access(u64 pte, int write, int user)
-{
-
-        if (user && !(pte & PT_USER_MASK))
-                return 0;
-        if (write && !(pte & PT_WRITABLE_MASK))
-                return 0;
-        return 1;
-}
-
 static void paging_free(struct kvm_vcpu *vcpu)
 {
         nonpaging_free(vcpu);