Patchwork [4/7] KVM: PPC: Book3S PR: Don't keep scanning HPTEG after we find a match

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Submitter Alexander Graf
Date June 30, 2013, 1:38 a.m.
Message ID <1372556328-18617-5-git-send-email-agraf@suse.de>
Download mbox | patch
Permalink /patch/255824/
State New
Headers show

Comments

Alexander Graf - June 30, 2013, 1:38 a.m.
From: Paul Mackerras <paulus@samba.org>

The loop in kvmppc_mmu_book3s_64_xlate() that looks up a translation
in the guest hashed page table (HPT) keeps going if it finds an
HPTE that matches but doesn't allow access.  This is incorrect; it
is different from what the hardware does, and there should never be
more than one matching HPTE anyway.  This fixes it to stop when any
matching HPTE is found.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
---
 arch/powerpc/kvm/book3s_64_mmu.c | 14 ++------------
 1 file changed, 2 insertions(+), 12 deletions(-)

Patch

diff --git a/arch/powerpc/kvm/book3s_64_mmu.c b/arch/powerpc/kvm/book3s_64_mmu.c
index b871721..2e93bb5 100644
--- a/arch/powerpc/kvm/book3s_64_mmu.c
+++ b/arch/powerpc/kvm/book3s_64_mmu.c
@@ -167,7 +167,6 @@  static int kvmppc_mmu_book3s_64_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
 	int i;
 	u8 key = 0;
 	bool found = false;
-	bool perm_err = false;
 	int second = 0;
 	ulong mp_ea = vcpu->arch.magic_page_ea;
 
@@ -248,11 +247,6 @@  do_second:
 				break;
 			}
 
-			if (!gpte->may_read) {
-				perm_err = true;
-				continue;
-			}
-
 			dprintk("KVM MMU: Translated 0x%lx [0x%llx] -> 0x%llx "
 				"-> 0x%lx\n",
 				eaddr, avpn, gpte->vpage, gpte->raddr);
@@ -281,6 +275,8 @@  do_second:
 		if (pteg[i+1] != oldr)
 			copy_to_user((void __user *)ptegp, pteg, sizeof(pteg));
 
+		if (!gpte->may_read)
+			return -EPERM;
 		return 0;
 	} else {
 		dprintk("KVM MMU: No PTE found (ea=0x%lx sdr1=0x%llx "
@@ -296,13 +292,7 @@  do_second:
 		}
 	}
 
-
 no_page_found:
-
-
-	if (perm_err)
-		return -EPERM;
-
 	return -ENOENT;
 
 no_seg_found: