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[Qemu-devel] [PATCH 2/2] xen-mapcache: pass the right size argument to t
From: |
Stefano Stabellini |
Subject: |
[Qemu-devel] [PATCH 2/2] xen-mapcache: pass the right size argument to test_bits |
Date: |
Tue, 2 Apr 2013 14:25:22 +0100 |
From: Hanweidong <address@hidden>
Compute the correct size for test_bits().
qemu_get_ram_ptr() and qemu_safe_ram_ptr() will call xen_map_cache()
with size is 0 if the requested address is in the RAM. Then
xen_map_cache() will pass the size 0 to test_bits() for checking if the
corresponding pfn was mapped in cache. But test_bits() will always
return 1 when size is 0 without any bit testing. Actually, for this
case, test_bits should check one bit. So this patch introduced a
__test_bit_size which is greater than 0 and a multiple of XC_PAGE_SIZE,
then test_bits can work correctly with __test_bit_size
>> XC_PAGE_SHIFT as its size.
Signed-off-by: Zhenguo Wang <address@hidden>
Signed-off-by: Weidong Han <address@hidden>
Signed-off-by: Stefano Stabellini <address@hidden>
---
xen-mapcache.c | 26 ++++++++++++++++++++++----
1 files changed, 22 insertions(+), 4 deletions(-)
diff --git a/xen-mapcache.c b/xen-mapcache.c
index a80cbdb..5a626cd 100644
--- a/xen-mapcache.c
+++ b/xen-mapcache.c
@@ -200,6 +200,7 @@ uint8_t *xen_map_cache(hwaddr phys_addr, hwaddr size,
hwaddr address_index;
hwaddr address_offset;
hwaddr __size = size;
+ hwaddr __test_bit_size = size;
bool translated = false;
tryagain:
@@ -208,9 +209,23 @@ tryagain:
trace_xen_map_cache(phys_addr);
+ /* __test_bit_size is always a multiple of XC_PAGE_SIZE */
+ if (size) {
+ __test_bit_size = size + (phys_addr & (XC_PAGE_SIZE - 1));
+
+ if (__test_bit_size % XC_PAGE_SIZE) {
+ __test_bit_size += XC_PAGE_SIZE - (__test_bit_size % XC_PAGE_SIZE);
+ }
+ } else {
+ __test_bit_size = XC_PAGE_SIZE;
+ }
+
if (mapcache->last_entry != NULL &&
mapcache->last_entry->paddr_index == address_index &&
- !lock && !__size) {
+ !lock && !__size &&
+ test_bits(address_offset >> XC_PAGE_SHIFT,
+ __test_bit_size >> XC_PAGE_SHIFT,
+ mapcache->last_entry->valid_mapping)) {
trace_xen_map_cache_return(mapcache->last_entry->vaddr_base +
address_offset);
return mapcache->last_entry->vaddr_base + address_offset;
}
@@ -229,7 +244,8 @@ tryagain:
while (entry && entry->lock && entry->vaddr_base &&
(entry->paddr_index != address_index || entry->size != __size ||
- !test_bits(address_offset >> XC_PAGE_SHIFT, size >> XC_PAGE_SHIFT,
+ !test_bits(address_offset >> XC_PAGE_SHIFT,
+ __test_bit_size >> XC_PAGE_SHIFT,
entry->valid_mapping))) {
pentry = entry;
entry = entry->next;
@@ -241,13 +257,15 @@ tryagain:
} else if (!entry->lock) {
if (!entry->vaddr_base || entry->paddr_index != address_index ||
entry->size != __size ||
- !test_bits(address_offset >> XC_PAGE_SHIFT, size >>
XC_PAGE_SHIFT,
+ !test_bits(address_offset >> XC_PAGE_SHIFT,
+ __test_bit_size >> XC_PAGE_SHIFT,
entry->valid_mapping)) {
xen_remap_bucket(entry, __size, address_index);
}
}
- if(!test_bits(address_offset >> XC_PAGE_SHIFT, size >> XC_PAGE_SHIFT,
+ if(!test_bits(address_offset >> XC_PAGE_SHIFT,
+ __test_bit_size >> XC_PAGE_SHIFT,
entry->valid_mapping)) {
mapcache->last_entry = NULL;
if (!translated && mapcache->phys_offset_to_gaddr) {
--
1.7.2.5
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