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migration/ram: Simplify host page handling in ram_load_postcopy() 

Add two new helper functions. This will come in come handy once we want to
handle ram block resizes while postcopy is active.

Note that ram_block_from_stream() will already print proper errors.

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20210429112708.12291-8-david@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
  dgilbert: Added brackets in host_page_from_ram_block_offset
     to cause uintptr_t to cast the sum, to fix armhf-cross build
This commit is contained in:
David Hildenbrand 2021-04-29 13:27:05 +02:00 committed by Dr. David Alan Gilbert
parent cc61c703b6
commit 6a23f6399a
1 changed files with 32 additions and 23 deletions
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55
migration/ram.c
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@ -3085,6 +3085,20 @@ static inline void *host_from_ram_block_offset(RAMBlock *block,
return block->host + offset;
}
static void *host_page_from_ram_block_offset(RAMBlock *block,
ram_addr_t offset)
{
/* Note: Explicitly no check against offset_in_ramblock(). */
return (void *)QEMU_ALIGN_DOWN((uintptr_t)(block->host + offset),
block->page_size);
}
static ram_addr_t host_page_offset_from_ram_block_offset(RAMBlock *block,
ram_addr_t offset)
{
return ((uintptr_t)block->host + offset) & (block->page_size - 1);
}
static inline void *colo_cache_from_block_offset(RAMBlock *block,
ram_addr_t offset, bool record_bitmap)
{
@ -3481,13 +3495,12 @@ static int ram_load_postcopy(QEMUFile *f)
MigrationIncomingState *mis = migration_incoming_get_current();
/* Temporary page that is later 'placed' */
void *postcopy_host_page = mis->postcopy_tmp_page;
void *this_host = NULL;
void *host_page = NULL;
bool all_zero = true;
int target_pages = 0;
while (!ret && !(flags & RAM_SAVE_FLAG_EOS)) {
ram_addr_t addr;
void *host = NULL;
void *page_buffer = NULL;
void *place_source = NULL;
RAMBlock *block = NULL;
@ -3512,9 +3525,12 @@ static int ram_load_postcopy(QEMUFile *f)
if (flags & (RAM_SAVE_FLAG_ZERO | RAM_SAVE_FLAG_PAGE |
RAM_SAVE_FLAG_COMPRESS_PAGE)) {
block = ram_block_from_stream(f, flags);
if (!block) {
ret = -EINVAL;
break;
}
host = host_from_ram_block_offset(block, addr);
if (!host) {
if (!offset_in_ramblock(block, addr)) {
error_report("Illegal RAM offset " RAM_ADDR_FMT, addr);
ret = -EINVAL;
break;
@ -3532,19 +3548,17 @@ static int ram_load_postcopy(QEMUFile *f)
* of a host page in one chunk.
*/
page_buffer = postcopy_host_page +
((uintptr_t)host & (block->page_size - 1));
host_page_offset_from_ram_block_offset(block, addr);
/* If all TP are zero then we can optimise the place */
if (target_pages == 1) {
this_host = (void *)QEMU_ALIGN_DOWN((uintptr_t)host,
block->page_size);
} else {
host_page = host_page_from_ram_block_offset(block, addr);
} else if (host_page != host_page_from_ram_block_offset(block,
addr)) {
/* not the 1st TP within the HP */
if (QEMU_ALIGN_DOWN((uintptr_t)host, block->page_size) !=
(uintptr_t)this_host) {
error_report("Non-same host page %p/%p",
host, this_host);
ret = -EINVAL;
break;
}
error_report("Non-same host page %p/%p", host_page,
host_page_from_ram_block_offset(block, addr));
ret = -EINVAL;
break;
}
/*
@ -3623,16 +3637,11 @@ static int ram_load_postcopy(QEMUFile *f)
}
if (!ret && place_needed) {
/* This gets called at the last target page in the host page */
void *place_dest = (void *)QEMU_ALIGN_DOWN((uintptr_t)host,
block->page_size);
if (all_zero) {
ret = postcopy_place_page_zero(mis, place_dest,
block);
ret = postcopy_place_page_zero(mis, host_page, block);
} else {
ret = postcopy_place_page(mis, place_dest,
place_source, block);
ret = postcopy_place_page(mis, host_page, place_source,
block);
}
place_needed = false;
target_pages = 0;