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migration/postcopy: Use uffd helpers

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Use the uffd_copy_page, uffd_zero_page and uffd_wakeup helpers
rather than calling ioctl ourselves.

They return -errno on error, and print an error_report themselves.
I think this actually makes postcopy_place_page actually more
consistent in it's callers.

Signed-off-by: Dr. David Alan Gilbert <dave@treblig.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20240919134626.166183-7-dave@treblig.org
[peterx: fix i386 build]
Signed-off-by: Peter Xu <peterx@redhat.com>
This commit is contained in:
Dr. David Alan Gilbert 2024-09-19 14:46:25 +01:00 committed by Peter Xu
parent 6f81bd1a3e
commit 3ba55a33e8
1 changed files with 14 additions and 34 deletions
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48
migration/postcopy-ram.c
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@ -746,18 +746,10 @@ int postcopy_wake_shared(struct PostCopyFD *pcfd,
RAMBlock *rb)
{
size_t pagesize = qemu_ram_pagesize(rb);
struct uffdio_range range;
int ret;
trace_postcopy_wake_shared(client_addr, qemu_ram_get_idstr(rb));
range.start = ROUND_DOWN(client_addr, pagesize);
range.len = pagesize;
ret = ioctl(pcfd->fd, UFFDIO_WAKE, &range);
if (ret) {
error_report("%s: Failed to wake: %zx in %s (%s)",
__func__, (size_t)client_addr, qemu_ram_get_idstr(rb),
strerror(errno));
}
return ret;
return uffd_wakeup(pcfd->fd,
(void *)(uintptr_t)ROUND_DOWN(client_addr, pagesize),
pagesize);
}
static int postcopy_request_page(MigrationIncomingState *mis, RAMBlock *rb,
@ -1275,18 +1267,10 @@ static int qemu_ufd_copy_ioctl(MigrationIncomingState *mis, void *host_addr,
int ret;
if (from_addr) {
struct uffdio_copy copy_struct;
copy_struct.dst = (uint64_t)(uintptr_t)host_addr;
copy_struct.src = (uint64_t)(uintptr_t)from_addr;
copy_struct.len = pagesize;
copy_struct.mode = 0;
ret = ioctl(userfault_fd, UFFDIO_COPY, &copy_struct);
ret = uffd_copy_page(userfault_fd, host_addr, from_addr, pagesize,
false);
} else {
struct uffdio_zeropage zero_struct;
zero_struct.range.start = (uint64_t)(uintptr_t)host_addr;
zero_struct.range.len = pagesize;
zero_struct.mode = 0;
ret = ioctl(userfault_fd, UFFDIO_ZEROPAGE, &zero_struct);
ret = uffd_zero_page(userfault_fd, host_addr, pagesize, false);
}
if (!ret) {
qemu_mutex_lock(&mis->page_request_mutex);
@ -1343,18 +1327,16 @@ int postcopy_place_page(MigrationIncomingState *mis, void *host, void *from,
RAMBlock *rb)
{
size_t pagesize = qemu_ram_pagesize(rb);
int e;
/* copy also acks to the kernel waking the stalled thread up
* TODO: We can inhibit that ack and only do it if it was requested
* which would be slightly cheaper, but we'd have to be careful
* of the order of updating our page state.
*/
if (qemu_ufd_copy_ioctl(mis, host, from, pagesize, rb)) {
int e = errno;
error_report("%s: %s copy host: %p from: %p (size: %zd)",
__func__, strerror(e), host, from, pagesize);
return -e;
e = qemu_ufd_copy_ioctl(mis, host, from, pagesize, rb);
if (e) {
return e;
}
trace_postcopy_place_page(host);
@ -1376,12 +1358,10 @@ int postcopy_place_page_zero(MigrationIncomingState *mis, void *host,
* but it's not available for everything (e.g. hugetlbpages)
*/
if (qemu_ram_is_uf_zeroable(rb)) {
if (qemu_ufd_copy_ioctl(mis, host, NULL, pagesize, rb)) {
int e = errno;
error_report("%s: %s zero host: %p",
__func__, strerror(e), host);
return -e;
int e;
e = qemu_ufd_copy_ioctl(mis, host, NULL, pagesize, rb);
if (e) {
return e;
}
return postcopy_notify_shared_wake(rb,
qemu_ram_block_host_offset(rb,