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xen/mapcache: introduce xen_replace_cache_entry()

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This new call is trying to update a requested map cache entry
according to the changes in the physmap. The call is searching
for the entry, unmaps it and maps again at the same place using
a new guest address. If the mapping is dummy this call will
make it real.

This function makes use of a new xenforeignmemory_map2() call
with an extended interface that was recently introduced in
libxenforeignmemory [1].

[1] https://www.mail-archive.com/xen-devel@lists.xen.org/msg113007.html

Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>
Reviewed-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
This commit is contained in:
Igor Druzhinin 2017-07-10 23:40:02 +01:00 • committed by Stefano Stabellini
parent 759235653d
commit 5ba3d75645
4 changed files with 119 additions and 9 deletions
Download patch file Download diff file Expand all files Collapse all files

85
hw/i386/xen/xen-mapcache.c
View file

@ -151,6 +151,7 @@ void xen_map_cache_init(phys_offset_to_gaddr_t f, void *opaque)
}
static void xen_remap_bucket(MapCacheEntry *entry,
void *vaddr,
hwaddr size,
hwaddr address_index,
bool dummy)
@ -167,7 +168,9 @@ static void xen_remap_bucket(MapCacheEntry *entry,
err = g_malloc0(nb_pfn * sizeof (int));
if (entry->vaddr_base != NULL) {
ram_block_notify_remove(entry->vaddr_base, entry->size);
if (!(entry->flags & XEN_MAPCACHE_ENTRY_DUMMY)) {
ram_block_notify_remove(entry->vaddr_base, entry->size);
}
if (munmap(entry->vaddr_base, entry->size) != 0) {
perror("unmap fails");
exit(-1);
@ -181,11 +184,11 @@ static void xen_remap_bucket(MapCacheEntry *entry,
}
if (!dummy) {
vaddr_base = xenforeignmemory_map(xen_fmem, xen_domid,
PROT_READ | PROT_WRITE,
vaddr_base = xenforeignmemory_map2(xen_fmem, xen_domid, vaddr,
PROT_READ | PROT_WRITE, 0,
nb_pfn, pfns, err);
if (vaddr_base == NULL) {
perror("xenforeignmemory_map");
perror("xenforeignmemory_map2");
exit(-1);
}
} else {
@ -193,7 +196,7 @@ static void xen_remap_bucket(MapCacheEntry *entry,
* We create dummy mappings where we are unable to create a foreign
* mapping immediately due to certain circumstances (i.e. on resume now)
*/
vaddr_base = mmap(NULL, size, PROT_READ | PROT_WRITE,
vaddr_base = mmap(vaddr, size, PROT_READ | PROT_WRITE,
MAP_ANON | MAP_SHARED, -1, 0);
if (vaddr_base == NULL) {
perror("mmap");
@ -201,6 +204,10 @@ static void xen_remap_bucket(MapCacheEntry *entry,
}
}
if (!(entry->flags & XEN_MAPCACHE_ENTRY_DUMMY)) {
ram_block_notify_add(vaddr_base, size);
}
entry->vaddr_base = vaddr_base;
entry->paddr_index = address_index;
entry->size = size;
@ -213,7 +220,6 @@ static void xen_remap_bucket(MapCacheEntry *entry,
entry->flags &= ~(XEN_MAPCACHE_ENTRY_DUMMY);
}
ram_block_notify_add(entry->vaddr_base, entry->size);
bitmap_zero(entry->valid_mapping, nb_pfn);
for (i = 0; i < nb_pfn; i++) {
if (!err[i]) {
@ -286,14 +292,14 @@ tryagain:
if (!entry) {
entry = g_malloc0(sizeof (MapCacheEntry));
pentry->next = entry;
xen_remap_bucket(entry, cache_size, address_index, dummy);
xen_remap_bucket(entry, NULL, cache_size, address_index, dummy);
} else if (!entry->lock) {
if (!entry->vaddr_base || entry->paddr_index != address_index ||
entry->size != cache_size ||
!test_bits(address_offset >> XC_PAGE_SHIFT,
test_bit_size >> XC_PAGE_SHIFT,
entry->valid_mapping)) {
xen_remap_bucket(entry, cache_size, address_index, dummy);
xen_remap_bucket(entry, NULL, cache_size, address_index, dummy);
}
}
@ -490,3 +496,66 @@ void xen_invalidate_map_cache(void)
mapcache_unlock();
}
static uint8_t *xen_replace_cache_entry_unlocked(hwaddr old_phys_addr,
hwaddr new_phys_addr,
hwaddr size)
{
MapCacheEntry *entry;
hwaddr address_index, address_offset;
hwaddr test_bit_size, cache_size = size;
address_index = old_phys_addr >> MCACHE_BUCKET_SHIFT;
address_offset = old_phys_addr & (MCACHE_BUCKET_SIZE - 1);
assert(size);
/* test_bit_size is always a multiple of XC_PAGE_SIZE */
test_bit_size = size + (old_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);
}
cache_size = size + address_offset;
if (cache_size % MCACHE_BUCKET_SIZE) {
cache_size += MCACHE_BUCKET_SIZE - (cache_size % MCACHE_BUCKET_SIZE);
}
entry = &mapcache->entry[address_index % mapcache->nr_buckets];
while (entry && !(entry->paddr_index == address_index &&
entry->size == cache_size)) {
entry = entry->next;
}
if (!entry) {
DPRINTF("Trying to update an entry for %lx " \
"that is not in the mapcache!\n", old_phys_addr);
return NULL;
}
address_index = new_phys_addr >> MCACHE_BUCKET_SHIFT;
address_offset = new_phys_addr & (MCACHE_BUCKET_SIZE - 1);
fprintf(stderr, "Replacing a dummy mapcache entry for %lx with %lx\n",
old_phys_addr, new_phys_addr);
xen_remap_bucket(entry, entry->vaddr_base,
cache_size, address_index, false);
if (!test_bits(address_offset >> XC_PAGE_SHIFT,
test_bit_size >> XC_PAGE_SHIFT,
entry->valid_mapping)) {
DPRINTF("Unable to update a mapcache entry for %lx!\n", old_phys_addr);
return NULL;
}
return entry->vaddr_base + address_offset;
}
uint8_t *xen_replace_cache_entry(hwaddr old_phys_addr,
hwaddr new_phys_addr,
hwaddr size)
{
uint8_t *p;
mapcache_lock();
p = xen_replace_cache_entry_unlocked(old_phys_addr, new_phys_addr, size);
mapcache_unlock();
return p;
}