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-rw-r--r--arch/x86/include/asm/xen/page.h31
-rw-r--r--arch/x86/xen/p2m.c10
2 files changed, 24 insertions, 17 deletions
diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index 6aef9fbc09b7..b913915e8e63 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -79,30 +79,38 @@ static inline int phys_to_machine_mapping_valid(unsigned long pfn)
return get_phys_to_machine(pfn) != INVALID_P2M_ENTRY;
}
-static inline unsigned long mfn_to_pfn(unsigned long mfn)
+static inline unsigned long mfn_to_pfn_no_overrides(unsigned long mfn)
{
unsigned long pfn;
- int ret = 0;
+ int ret;
if (xen_feature(XENFEAT_auto_translated_physmap))
return mfn;
- if (unlikely(mfn >= machine_to_phys_nr)) {
- pfn = ~0;
- goto try_override;
- }
- pfn = 0;
+ if (unlikely(mfn >= machine_to_phys_nr))
+ return ~0;
+
/*
* The array access can fail (e.g., device space beyond end of RAM).
* In such cases it doesn't matter what we return (we return garbage),
* but we must handle the fault without crashing!
*/
ret = __get_user(pfn, &machine_to_phys_mapping[mfn]);
-try_override:
- /* ret might be < 0 if there are no entries in the m2p for mfn */
if (ret < 0)
- pfn = ~0;
- else if (get_phys_to_machine(pfn) != mfn)
+ return ~0;
+
+ return pfn;
+}
+
+static inline unsigned long mfn_to_pfn(unsigned long mfn)
+{
+ unsigned long pfn;
+
+ if (xen_feature(XENFEAT_auto_translated_physmap))
+ return mfn;
+
+ pfn = mfn_to_pfn_no_overrides(mfn);
+ if (get_phys_to_machine(pfn) != mfn) {
/*
* If this appears to be a foreign mfn (because the pfn
* doesn't map back to the mfn), then check the local override
@@ -111,6 +119,7 @@ try_override:
* m2p_find_override_pfn returns ~0 if it doesn't find anything.
*/
pfn = m2p_find_override_pfn(mfn, ~0);
+ }
/*
* pfn is ~0 if there are no entries in the m2p for mfn or if the
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 8b901e8d782d..a61c7d5811be 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -879,7 +879,6 @@ int m2p_add_override(unsigned long mfn, struct page *page,
unsigned long uninitialized_var(address);
unsigned level;
pte_t *ptep = NULL;
- int ret = 0;
pfn = page_to_pfn(page);
if (!PageHighMem(page)) {
@@ -926,8 +925,8 @@ int m2p_add_override(unsigned long mfn, struct page *page,
* frontend pages while they are being shared with the backend,
* because mfn_to_pfn (that ends up being called by GUPF) will
* return the backend pfn rather than the frontend pfn. */
- ret = __get_user(pfn, &machine_to_phys_mapping[mfn]);
- if (ret == 0 && get_phys_to_machine(pfn) == mfn)
+ pfn = mfn_to_pfn_no_overrides(mfn);
+ if (get_phys_to_machine(pfn) == mfn)
set_phys_to_machine(pfn, FOREIGN_FRAME(mfn));
return 0;
@@ -942,7 +941,6 @@ int m2p_remove_override(struct page *page,
unsigned long uninitialized_var(address);
unsigned level;
pte_t *ptep = NULL;
- int ret = 0;
pfn = page_to_pfn(page);
mfn = get_phys_to_machine(pfn);
@@ -1029,8 +1027,8 @@ int m2p_remove_override(struct page *page,
* the original pfn causes mfn_to_pfn(mfn) to return the frontend
* pfn again. */
mfn &= ~FOREIGN_FRAME_BIT;
- ret = __get_user(pfn, &machine_to_phys_mapping[mfn]);
- if (ret == 0 && get_phys_to_machine(pfn) == FOREIGN_FRAME(mfn) &&
+ pfn = mfn_to_pfn_no_overrides(mfn);
+ if (get_phys_to_machine(pfn) == FOREIGN_FRAME(mfn) &&
m2p_find_override(mfn) == NULL)
set_phys_to_machine(pfn, mfn);