Commit Graph

13 Commits

Author SHA1 Message Date
Kevin Wolf 4fabffc112 Specification for qcow2 version 3
This updates the qcow2 specification to cover version 3. It contains the
following changes:

- Added compatible/incompatible/auto-clear feature bits plus an optional
  feature name table to allow useful error messages even if an older
  version doesn't know some feature at all.

- Configurable refcount width. If you don't want to use internal
  snapshots, make refcounts one bit and save cache space and I/O.

- Zero cluster flags. This allows discard even with a backing file that
  doesn't contain zeros. It is also useful for copy-on-read/image
  streaming, as you'll want to keep sparseness without accessing the
  remote image for an unallocated cluster all the time.

- Fixed internal snapshot metadata to use 64 bit VM state size. You
  can't save a snapshot of a VM with >= 4 GB RAM today.

- Extended internal snapshot metadata to contain the disk size, so that
  resizing images that have snapshots can be allowed in the future.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-20 15:57:27 +02:00
Alex Williamson 9290f364c1 acpi_piix4: Re-define PCI hotplug eject register read
The PCI hotplug eject register has always returned 0, so let's redefine
it as a hotplug feature register.  The existing model of using separate
up & down read-only registers and an eject via write to this register
becomes the base implementation.  As we make use of new interfaces we'll
set bits here to allow the BIOS and AML implementation to optimize for
the platform implementation.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2012-04-15 12:17:23 +03:00
Alex Williamson 31745aabcd acpi_piix4: Remove PCI_RMV_BASE write code
Clarify this register as read-only and remove write code.  No
change in existing behavior.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2012-04-15 12:17:23 +03:00
Alex Williamson ba737541ed acpi_piix4: Disallow write to up/down PCI hotplug registers
The write side of these registers is never used and actually can't be
used as defined because any read/modify/write sequence from the guest
potentially races with qemu.  Drop the write support and define these
as read-only registers.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2012-04-15 12:17:22 +03:00
Stefan Weil 6576b74b0b Replace Qemu by QEMU in internal documentation
The official spelling is QEMU.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2012-04-07 13:58:25 +00:00
Kevin Wolf c2c9a46609 qcow2: Allow >4 GB VM state
This is a compatible extension to the snapshot header format that allows
saving a 64 bit VM state size.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-15 12:40:33 +01:00
Zhi Yong Wu 3789985f40 qcow2: fix some errors and typo in qcow2.txt
Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-28 19:25:49 +02:00
Stefan Hajnoczi d54f10bba7 docs: Describe zero data clusters in QED specification
Zero data clusters are a space-efficient way of storing zeroed regions
of the image.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-04-13 12:06:40 +02:00
Kevin Wolf 03feae7305 Add qcow2 documentation
This adds a description of the qcow2 file format to the docs/ directory.
Besides documenting what's there, which is never wrong, the document should
provide a good basis for the discussion of format extensions (called "qcow3"
in previous discussions)

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2011-03-16 09:56:18 +01:00
Marcelo Tosatti 9c046d96d4 document QEMU<->ACPIBIOS PCI hotplug interface
Document how QEMU communicates with ACPI BIOS for PCI hotplug.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2011-01-17 17:29:42 +02:00
Stefan Hajnoczi e59d688ad1 docs: Fix missing carets in QED specification
For some reason the carets ('^') in the QED specification disappeared.
This patch puts them back.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-12-17 17:05:06 +01:00
Stefan Hajnoczi 71af014f14 docs: Add QED image format specification
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-12-17 16:11:04 +01:00
Cam Macdonell b6828931eb Device specification for shared memory PCI device
Signed-off-by: Cam Macdonell <cam@cs.ualberta.ca>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2010-08-10 16:25:15 -05:00