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xen-mapcache: pass the right size argument to test_bits

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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 <wangzhenguo@huawei.com>
Signed-off-by: Weidong Han <hanweidong@huawei.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
This commit is contained in:
Hanweidong 2013-04-02 13:22:41 +00:00 committed by Stefano Stabellini
parent e2deee3ea6
commit 044d4e1aae
1 changed files with 22 additions and 4 deletions
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26
xen-mapcache.c
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@ -200,6 +200,7 @@ uint8_t *xen_map_cache(hwaddr phys_addr, hwaddr size,
hwaddr address_index; hwaddr address_index;
hwaddr address_offset; hwaddr address_offset;
hwaddr __size = size; hwaddr __size = size;
hwaddr __test_bit_size = size;
bool translated = false; bool translated = false;
tryagain: tryagain:
@ -208,9 +209,23 @@ tryagain:
trace_xen_map_cache(phys_addr); 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 && if (mapcache->last_entry != NULL &&
mapcache->last_entry->paddr_index == address_index && 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); trace_xen_map_cache_return(mapcache->last_entry->vaddr_base + address_offset);
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 && while (entry && entry->lock && entry->vaddr_base &&
(entry->paddr_index != address_index || entry->size != __size || (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))) { entry->valid_mapping))) {
pentry = entry; pentry = entry;
entry = entry->next; entry = entry->next;
@ -241,13 +257,15 @@ tryagain:
} else if (!entry->lock) { } else if (!entry->lock) {
if (!entry->vaddr_base || entry->paddr_index != address_index || if (!entry->vaddr_base || entry->paddr_index != address_index ||
entry->size != __size || 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)) { entry->valid_mapping)) {
xen_remap_bucket(entry, __size, address_index); 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)) { entry->valid_mapping)) {
mapcache->last_entry = NULL; mapcache->last_entry = NULL;
if (!translated && mapcache->phys_offset_to_gaddr) { if (!translated && mapcache->phys_offset_to_gaddr) {