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[Qemu-devel] [PATCH 36/45] mmu-hash*: Don't update PTE flags when permis
From: |
David Gibson |
Subject: |
[Qemu-devel] [PATCH 36/45] mmu-hash*: Don't update PTE flags when permission is denied |
Date: |
Wed, 6 Mar 2013 14:44:24 +1100 |
BEHAVIOUR CHANGE
Currently if ppc_hash{32,64}_translate() finds a PTE matching the given
virtual address, it will always update the PTE's R & C (Referenced and
Changed) bits. This happens even if the PTE's permissions mean we are
about to deny the translation.
This is clearly a bug, although we get away with it because:
a) It will only incorrectly set, never reset the bits, which should not
cause guest correctness problems.
b) Linux guests never use the R & C bits anyway.
This patch fixes the behaviour, only updating R & C when access is granted
by the PTE.
Signed-off-by: David Gibson <address@hidden>
---
target-ppc/mmu-hash32.c | 12 +++++++-----
target-ppc/mmu-hash64.c | 12 +++++++-----
2 files changed, 14 insertions(+), 10 deletions(-)
diff --git a/target-ppc/mmu-hash32.c b/target-ppc/mmu-hash32.c
index 3488092..ae606fd 100644
--- a/target-ppc/mmu-hash32.c
+++ b/target-ppc/mmu-hash32.c
@@ -439,15 +439,17 @@ static int ppc_hash32_translate(CPUPPCState *env, struct
mmu_ctx_hash32 *ctx,
ctx->raddr = pte.pte1;
ctx->prot = access;
ret = ppc_hash32_check_prot(ctx->prot, rwx);
- if (ret == 0) {
- /* Access granted */
- LOG_MMU("PTE access granted !\n");
- } else {
+
+ if (ret) {
/* Access right violation */
LOG_MMU("PTE access rejected\n");
+ return ret;
}
- /* Update page flags */
+ LOG_MMU("PTE access granted !\n");
+
+ /* 8. Update PTE referenced and changed bits if necessary */
+
if (ppc_hash32_pte_update_flags(ctx, &pte.pte1, ret, rwx) == 1) {
ppc_hash32_store_hpte1(env, pte_offset, pte.pte1);
}
diff --git a/target-ppc/mmu-hash64.c b/target-ppc/mmu-hash64.c
index 2e109f4..f7aa352 100644
--- a/target-ppc/mmu-hash64.c
+++ b/target-ppc/mmu-hash64.c
@@ -460,15 +460,17 @@ static int ppc_hash64_translate(CPUPPCState *env, struct
mmu_ctx_hash64 *ctx,
ctx->raddr = pte.pte1;
ctx->prot = access;
ret = ppc_hash64_check_prot(ctx->prot, rwx);
- if (ret == 0) {
- /* Access granted */
- LOG_MMU("PTE access granted !\n");
- } else {
+
+ if (ret) {
/* Access right violation */
LOG_MMU("PTE access rejected\n");
+ return ret;
}
- /* Update page flags */
+ LOG_MMU("PTE access granted !\n");
+
+ /* 6. Update PTE referenced and changed bits if necessary */
+
if (ppc_hash64_pte_update_flags(ctx, &pte.pte1, ret, rwx) == 1) {
ppc_hash64_store_hpte1(env, pte_offset, pte.pte1);
}
--
1.7.10.4
- [Qemu-devel] [PATCH 25/45] mmu-hash*: Don't keep looking for PTEs after we find a match, (continued)
- [Qemu-devel] [PATCH 25/45] mmu-hash*: Don't keep looking for PTEs after we find a match, David Gibson, 2013/03/05
- [Qemu-devel] [PATCH 27/45] mmu-hash*: Make find_pte{32, 64} do more of the job of finding ptes, David Gibson, 2013/03/05
- [Qemu-devel] [PATCH 28/45] mmu-hash*: Remove permission checking from find_pte{32, 64}(), David Gibson, 2013/03/05
- [Qemu-devel] [PATCH 32/45] mmu-hash32: Split BAT size logic from permissions logic, David Gibson, 2013/03/05
- [Qemu-devel] [PATCH 26/45] mmu-hash*: Separate PTEG searching from permissions checking, David Gibson, 2013/03/05
- [Qemu-devel] [PATCH 30/45] mmu-hash*: Fold pte_check*() logic into caller, David Gibson, 2013/03/05
- [Qemu-devel] [PATCH 35/45] mmu-hash32: Don't look up page tables on BAT permission error, David Gibson, 2013/03/05
- [Qemu-devel] [PATCH 31/45] mmu-hash32: Remove odd pointer usage from BAT code, David Gibson, 2013/03/05
- [Qemu-devel] [PATCH 37/45] mmu-hash32: Remove nx from context structure, David Gibson, 2013/03/05
- [Qemu-devel] [PATCH 33/45] mmu-hash32: Clean up BAT matching logic, David Gibson, 2013/03/05
- [Qemu-devel] [PATCH 36/45] mmu-hash*: Don't update PTE flags when permission is denied,
David Gibson <=
- [Qemu-devel] [PATCH 34/45] mmu-hash32: Cleanup BAT lookup, David Gibson, 2013/03/05
- [Qemu-devel] [PATCH 39/45] mmu-hash64: Factor SLB N bit into permissions bits, David Gibson, 2013/03/05
- [Qemu-devel] [PATCH 42/45] mmu-hash*: Correctly mask RPN from hash PTE, David Gibson, 2013/03/05
- [Qemu-devel] [PATCH 41/45] mmu-hash*: Clean up real address calculation, David Gibson, 2013/03/05
- [Qemu-devel] [PATCH 40/45] mmu-hash*: Clean up PTE flags update, David Gibson, 2013/03/05
- [Qemu-devel] [PATCH 38/45] mmu-hash*: Clean up permission checking, David Gibson, 2013/03/05
- [Qemu-devel] [PATCH 43/45] mmu-hash*: Don't use full ppc_hash{32, 64}_translate() path for get_phys_page_debug(), David Gibson, 2013/03/05
- [Qemu-devel] [PATCH 44/45] mmu-hash*: Merge translate and fault handling functions, David Gibson, 2013/03/05
- [Qemu-devel] [PATCH 45/45] mmu-hash64: Implement Virtual Page Class Key Protection, David Gibson, 2013/03/05