Add support for booting guests to host block devices in read-only mode.
Cc: Asias He <asias.he...@gmail.com>
Cc: Cyrill Gorcunov <gorcu...@gmail.com>
Cc: Prasad Joshi <prasadjoshi...@gmail.com>
Cc: Sasha Levin <levinsasha...@gmail.com>
Cc: Ingo Molnar <mi...@elte.hu>
Signed-off-by: Pekka Enberg <penb...@kernel.org>
---
tools/kvm/disk-image.c | 39 +++++++++++++++++++++++++++++++--------
1 files changed, 31 insertions(+), 8 deletions(-)
diff --git a/tools/kvm/disk-image.c b/tools/kvm/disk-image.c
index fff71b4..f5e11b9 100644
--- a/tools/kvm/disk-image.c
+++ b/tools/kvm/disk-image.c
@@ -4,6 +4,9 @@
#include "kvm/qcow.h"
#include "kvm/util.h"
+#include <linux/fs.h> /* for BLKGETSIZE64 */
+
+#include <sys/ioctl.h>
#include <sys/types.h>
#include <inttypes.h>
#include <sys/mman.h>
@@ -110,24 +113,44 @@ static struct disk_image_operations raw_image_ro_mmap_ops
= {
.close = raw_image__close_sector_ro_mmap,
};
-static struct disk_image *raw_image__probe(int fd, bool readonly)
+static struct disk_image *raw_image__probe(int fd, struct stat *st, bool
readonly)
{
- struct stat st;
+ if (readonly)
+ return disk_image__new_readonly(fd, st->st_size,
&raw_image_ro_mmap_ops);
+ else
+ return disk_image__new(fd, st->st_size, &raw_image_ops);
+}
- if (fstat(fd, &st) < 0)
+static struct disk_image *blkdev__probe(const char *filename, struct stat *st)
+{
+ uint64_t size;
+ int fd;
+
+ if (!S_ISBLK(st->st_mode))
return NULL;
- if (readonly)
- return disk_image__new_readonly(fd, st.st_size,
&raw_image_ro_mmap_ops);
- else
- return disk_image__new(fd, st.st_size, &raw_image_ops);
+ fd = open(filename, O_RDONLY);
+ if (fd < 0)
+ return NULL;
+
+ if (ioctl(fd, BLKGETSIZE64, &size) < 0)
+ return NULL;
+
+ return disk_image__new_readonly(fd, size, &raw_image_ro_mmap_ops);
}
struct disk_image *disk_image__open(const char *filename, bool readonly)
{
struct disk_image *self;
+ struct stat st;
int fd;
+ if (stat(filename, &st) < 0)
+ return NULL;
+
+ if (S_ISBLK(st.st_mode))
+ return blkdev__probe(filename, &st);
+
fd = open(filename, readonly ? O_RDONLY : O_RDWR);
if (fd < 0)
return NULL;
@@ -136,7 +159,7 @@ struct disk_image *disk_image__open(const char *filename,
bool readonly)
if (self)
return self;
- self = raw_image__probe(fd, readonly);
+ self = raw_image__probe(fd, &st, readonly);
if (self)
return self;
--
1.7.0.4
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