From 3ba55a33e82c9902c211d6325bc550afcca7ddf9 Mon Sep 17 00:00:00 2001 From: "Dr. David Alan Gilbert" Date: Thu, 19 Sep 2024 14:46:25 +0100 Subject: [PATCH] migration/postcopy: Use uffd helpers 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 Reviewed-by: Peter Xu Link: https://lore.kernel.org/r/20240919134626.166183-7-dave@treblig.org [peterx: fix i386 build] Signed-off-by: Peter Xu --- migration/postcopy-ram.c | 48 ++++++++++++---------------------------- 1 file changed, 14 insertions(+), 34 deletions(-) diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c index 0fe9d83d44..83f6160a36 100644 --- a/migration/postcopy-ram.c +++ b/migration/postcopy-ram.c @@ -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, ©_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,