motorhead/qemu
1
0
Fork 0
mirror of https://github.com/Motorhead1991/qemu.git synced 2025-08-06 09:13:55 -06:00
Code Issues Projects Releases Packages Wiki Activity Actions

Memory: Enable writeback for given memory region

Browse source 
Add an option to trigger memory writeback to sync given memory region
with the corresponding backing store, case one is available.
This extends the support for persistent memory, allowing syncing on-demand.

Signed-off-by: Beata Michalska <beata.michalska@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20191121000843.24844-3-beata.michalska@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Beata Michalska 2019-11-21 00:08:41 +00:00 • committed by Peter Maydell
parent 9e70492b43
commit 61c490e25e
6 changed files with 101 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

38
util/cutils.c
View file

@ -164,6 +164,44 @@ int qemu_fdatasync(int fd)
#endif
}
/**
* Sync changes made to the memory mapped file back to the backing
* storage. For POSIX compliant systems this will fallback
* to regular msync call. Otherwise it will trigger whole file sync
* (including the metadata case there is no support to skip that otherwise)
*
* @addr - start of the memory area to be synced
* @length - length of the are to be synced
* @fd - file descriptor for the file to be synced
* (mandatory only for POSIX non-compliant systems)
*/
int qemu_msync(void *addr, size_t length, int fd)
{
#ifdef CONFIG_POSIX
size_t align_mask = ~(qemu_real_host_page_size - 1);
/**
* There are no strict reqs as per the length of mapping
* to be synced. Still the length needs to follow the address
* alignment changes. Additionally - round the size to the multiple
* of PAGE_SIZE
*/
length += ((uintptr_t)addr & (qemu_real_host_page_size - 1));
length = (length + ~align_mask) & align_mask;
addr = (void *)((uintptr_t)addr & align_mask);
return msync(addr, length, MS_SYNC);
#else /* CONFIG_POSIX */
/**
* Perform the sync based on the file descriptor
* The sync range will most probably be wider than the one
* requested - but it will still get the job done
*/
return qemu_fdatasync(fd);
#endif /* CONFIG_POSIX */
}
#ifndef _WIN32
/* Sets a specific flag */
int fcntl_setfl(int fd, int flag)