If a user decides to punish a guest by revoking its block device via
drive_del, and subsequently also attempts to remove the pci device
backing it, and the device is using blockdev_auto_del() then we get a
segfault when we attempt to access dinfo->auto_del.[1]

The fix is to check if drive_get_by_blockdev() actually returns a valid
dinfo pointer or not.

1. (qemu) pci_add auto storage file=images/test01.raw,if=virtio,id=block1,snapshot=on
   (qemu) drive_del block1
   (qemu) pci_del 5
   *segfault*
Signed-off-by: NRyan Harper <ryanh@us.ibm.com>
Tested-by: NLuiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Currently device hotplug removal code is tied to device removal via
ACPI.  All pci devices that are removable via device_del() require the
guest to respond to the request.  In some cases the guest may not
respond leaving the device still accessible to the guest.  The management
layer doesn't currently have a reliable way to revoke access to host
resource in the presence of an uncooperative guest.

This patch implements a new monitor command, drive_del, which
provides an explicit command to revoke access to a host block device.

drive_del first quiesces the block device (qemu_aio_flush;
bdrv_flush() and bdrv_close()).  This prevents further IO from being
submitted against the host device.  Finally, drive_del cleans up
pointers between the drive object (host resource) and the device
object (guest resource).
Signed-off-by: NRyan Harper <ryanh@us.ibm.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This implements the rerror option for SCSI disks.

It also includes minor changes to the write path where the same code is used
that was criticized in the review for the changes to the read path required for
rerror support.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>

Switch tree to lookup-by-name using qemu_find_opts().
Also hook up virtfs options so qemu_find_opts works for them too.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Block device change command did not copy BDRV_O_SNAPSHOT flag. Thus
the new image did not have this flag and the file got deleted during
opening.

Fix by copying BDRV_O_SNAPSHOT flag.
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Since commit cb4e5f8e, monitor command change makes the new media
readonly iff the type hint is BDRV_TYPE_CDROM, i.e. the drive was
created with media=cdrom.  The intention is to avoid changing a block
device's read-only-ness.  However, BDRV_TYPE_CDROM is only a hint.  It
is currently sufficent for read-only.  But it's not necessary, and it
may not remain sufficient.

Use bdrv_is_read_only() instead.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

We automatically delete blockdev host parts on unplug of the guest
device.  Too much magic, but we can't change that now.

The delete happens early in the guest device teardown, before the
connection to the host part is severed.  Thus, the guest part's
pointer to the host part dangles for a brief time.  No actual harm
comes from this, but we'll catch such dangling pointers a few commits
down the road.  Clean up the dangling pointers by delaying the
automatic deletion until the guest part's pointer is gone.

Device usb-storage deliberately makes two qdev properties refer to the
same drive, because it automatically creates a second device.  Again,
too much magic we can't change now.  Multiple references worked okay
before, but now free_drive() dies for the second one.  Zap the extra
reference.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Unused since commit 6ced55a5.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Historically, user monitor arguments beginning with '-' (eg. '-f')
were passed as integers down to handlers.

I've maintained this behavior in the new monitor because we didn't
have a boolean type at the very beginning of QMP. Today we have it
and this behavior is causing trouble to QMP's argument checker.

This commit fixes the problem by doing the following changes:

1. User Monitor

   Before: the optional arg was represented as a QInt, we'd pass 1
           down to handlers if the user specified the argument or
           0 otherwise

   This commit: the optional arg is represented as a QBool, we pass
                true down to handlers if the user specified the
                argument, otherwise _nothing_ is passed

2. QMP

   Before: the client was required to pass the arg as QBool, but we'd
           convert it to QInt internally. If the argument wasn't passed,
           we'd pass 0 down

   This commit: still require a QBool, but doesn't do any conversion and
                doesn't pass any default value

3. Convert existing handlers (do_eject()/do_migrate()) to the new way

   Before: Both handlers would expect a QInt value, either 0 or 1

   This commit: Change the handlers to accept a QBool, they handle the
                following cases:

                   A) true is passed: the option is enabled
                   B) false is passed: the option is disabled
                   C) nothing is passed: option not specified, use
                                         default behavior
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>

This changes the monitor eject_device() function to not check for
bdrv_is_inserted().

Example run where the bug manifests itself:

(output of 'info block' is stripped to include only the CD-ROM device)

  (qemu) info block
  ide1-cd0: type=cdrom removable=1 locked=0 [not inserted]
  (qemu) change ide1-cd0 /dev/cdrom host_cdrom
  (qemu) info block
  ide1-cd0: type=cdrom removable=1 locked=0 file=/dev/cdrom ro=1 drv=host_cdrom encrypted=0
  (qemu) eject ide1-cd0
  (qemu) info block
  ide1-cd0: type=cdrom removable=1 locked=0 file=/dev/cdrom ro=1 drv=host_cdrom encrypted=0

  # at this point, a disk was inserted on the host CD-ROM drive

  (qemu) info block
  ide1-cd0: type=cdrom removable=1 locked=0 file=/dev/cdrom ro=1 drv=host_cdrom encrypted=0
  (qemu) eject ide1-cd0
  (qemu) info block
  ide1-cd0: type=cdrom removable=1 locked=0 [not inserted]
  (qemu)

The first eject command didn't work because the is_inserted() check
failed.

I have no clue why the code had the is_inserted() check, as it doesn't matter
if there is a disk present at the host drive, when the user wants the virtual
device to be disconnected from the host device.

The is_inserted() check has another side effect: a memory leak if the "change"
command is used multiple times, as do_change() calls eject_device() before
re-opening the block device, but bdrv_close() is never called.
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This is the list of drives defined with drive_init().  Hide it, so it
doesn't get abused.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

do_commit() and mux_proc_byte() iterate over the list of drives
defined with drive_init().  This misses host block devices defined by
other means.  Such means don't exist now, but will be introduced later
in this series.

Change them to use new bdrv_commit_all(), which iterates over all host
block devices.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

That's where they belong semantically (block device host part), even
though the actions are actually executed by guest device code.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Empty file used to create an empty drive (no media).  Since commit
9dfd7c7a, it's an error: "qemu: could not open disk image : No such
file or directory".  Older versions of libvirt can choke on this.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

We should use 'dinfo->serial' length, 'serial' is a pointer, so
the serial number length is currently limited to the pointer size.

This fixes https://bugs.launchpad.net/qemu/+bug/584143 and is also
valid for stable.
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Anything that moves hundreds of lines out of vl.c can't be all bad.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>