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authorStefan Hajnoczi <stefanha@redhat.com>2019-08-30 10:30:56 +0100
committerPaolo Bonzini <pbonzini@redhat.com>2019-09-16 12:32:21 +0200
commit72d41eb4b8f923de91e8f06dc20aa86b0a9155fb (patch)
treef7983fc765558472fc89962142374e4c6f286869 /backends
parent41a2635124117d1fac7e45b3cafa2c1ac68417fd (diff)
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memory: fetch pmem size in get_file_size()
Neither stat(2) nor lseek(2) report the size of Linux devdax pmem character device nodes. Commit 314aec4a6e06844937f1677f6cba21981005f389 ("hostmem-file: reject invalid pmem file sizes") added code to hostmem-file.c to fetch the size from sysfs and compare against the user-provided size=NUM parameter: if (backend->size > size) { error_setg(errp, "size property %" PRIu64 " is larger than " "pmem file \"%s\" size %" PRIu64, backend->size, fb->mem_path, size); return; } It turns out that exec.c:qemu_ram_alloc_from_fd() already has an equivalent size check but it skips devdax pmem character devices because lseek(2) returns 0: if (file_size > 0 && file_size < size) { error_setg(errp, "backing store %s size 0x%" PRIx64 " does not match 'size' option 0x" RAM_ADDR_FMT, mem_path, file_size, size); return NULL; } This patch moves the devdax pmem file size code into get_file_size() so that we check the memory size in a single place: qemu_ram_alloc_from_fd(). This simplifies the code and makes it more general. This also fixes the problem that hostmem-file only checks the devdax pmem file size when the pmem=on parameter is given. An unchecked size=NUM parameter can lead to SIGBUS in QEMU so we must always fetch the file size for Linux devdax pmem character device nodes. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20190830093056.12572-1-stefanha@redhat.com> Reviewed-by: Eduardo Habkost <ehabkost@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'backends')
-rw-r--r--backends/hostmem-file.c22
1 files changed, 0 insertions, 22 deletions
diff --git a/backends/hostmem-file.c b/backends/hostmem-file.c
index ecc15e3..be64020 100644
--- a/backends/hostmem-file.c
+++ b/backends/hostmem-file.c
@@ -58,28 +58,6 @@ file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)
return;
}
- /*
- * Verify pmem file size since starting a guest with an incorrect size
- * leads to confusing failures inside the guest.
- */
- if (fb->is_pmem) {
- Error *local_err = NULL;
- uint64_t size;
-
- size = qemu_get_pmem_size(fb->mem_path, &local_err);
- if (local_err) {
- error_propagate(errp, local_err);
- return;
- }
-
- if (size && backend->size > size) {
- error_setg(errp, "size property %" PRIu64 " is larger than "
- "pmem file \"%s\" size %" PRIu64, backend->size,
- fb->mem_path, size);
- return;
- }
- }
-
backend->force_prealloc = mem_prealloc;
name = host_memory_backend_get_name(backend);
memory_region_init_ram_from_file(&backend->mr, OBJECT(backend),