From ca7611abb178a1c2c7a3fd9c62d7c54369bffea1 Mon Sep 17 00:00:00 2001 From: William Roche Date: Tue, 21 Jan 2025 22:54:26 +0000 Subject: [PATCH] system/physmem: take into account fd_offset for file fallocate Punching a hole in a file with fallocate needs to take into account the fd_offset value for a correct file location. But guest_memfd internal use doesn't currently consider fd_offset. Fixes: 4b870dc4d0c0 ("hostmem-file: add offset option") Signed-off-by: William Roche --- system/physmem.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/system/physmem.c b/system/physmem.c index c76503aea82..7e4da793112 100644 --- a/system/physmem.c +++ b/system/physmem.c @@ -3655,6 +3655,7 @@ int ram_block_discard_range(RAMBlock *rb, uint64_t start, size_t length) need_madvise = (rb->page_size == qemu_real_host_page_size()); need_fallocate = rb->fd != -1; if (need_fallocate) { + uint64_t file_offset = start + rb->fd_offset; /* For a file, this causes the area of the file to be zero'd * if read, and for hugetlbfs also causes it to be unmapped * so a userfault will trigger. @@ -3689,18 +3690,18 @@ int ram_block_discard_range(RAMBlock *rb, uint64_t start, size_t length) } ret = fallocate(rb->fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, - start, length); + file_offset, length); if (ret) { ret = -errno; error_report("%s: Failed to fallocate %s:%" PRIx64 " +%zx (%d)", - __func__, rb->idstr, start, length, ret); + __func__, rb->idstr, file_offset, length, ret); goto err; } #else ret = -ENOSYS; error_report("%s: fallocate not available/file" "%s:%" PRIx64 " +%zx (%d)", - __func__, rb->idstr, start, length, ret); + __func__, rb->idstr, file_offset, length, ret); goto err; #endif } @@ -3747,6 +3748,7 @@ int ram_block_discard_guest_memfd_range(RAMBlock *rb, uint64_t start, int ret = -1; #ifdef CONFIG_FALLOCATE_PUNCH_HOLE + /* ignore fd_offset with guest_memfd */ ret = fallocate(rb->guest_memfd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, start, length);