blkdebug: Make required alignment configurable

The new 'align' option of blkdebug can be used in order to emulate
backends with a required 4k alignment on hosts which only really require
512 byte alignment.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/block/blkdebug.c b/block/blkdebug.c
index c8f8d56758..2c03698f93 100644
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -364,6 +364,11 @@ static QemuOptsList runtime_opts = {
             .type = QEMU_OPT_STRING,
             .help = "[internal use only, will be removed]",
         },
+        {
+            .name = "align",
+            .type = QEMU_OPT_SIZE,
+            .help = "Required alignment in bytes",
+        },
         { /* end of list */ }
     },
 };
@@ -375,6 +380,7 @@ static int blkdebug_open(BlockDriverState *bs, QDict *options, int flags,
     QemuOpts *opts;
     Error *local_err = NULL;
     const char *config;
+    uint64_t align;
     int ret;
 
     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
@@ -403,6 +409,16 @@ static int blkdebug_open(BlockDriverState *bs, QDict *options, int flags,
         goto fail;
     }
 
+    /* Set request alignment */
+    align = qemu_opt_get_size(opts, "align", bs->request_alignment);
+    if (align > 0 && align < INT_MAX && !(align & (align - 1))) {
+        bs->request_alignment = align;
+    } else {
+        error_setg(errp, "Invalid alignment");
+        ret = -EINVAL;
+        goto fail;
+    }
+
     ret = 0;
 fail:
     qemu_opts_del(opts);