On 01/20/2016 09:51 AM, John Snow wrote:
requires: 1448895398-13465-1-git-send-email-ehabk...@redhat.com pc: Add pc-*-2.6 machine classesYes, it's been broken for ten years. No, it's not a CVE. The problem is that QEMU doesn't have a configuration option for the type of floppy drive you want. It determines that based on the type of diskette inserted at boot time. If you don't insert one, it always chooses a 1.44MB type. If you want to insert a 2.88MB floppy after boot, you simply cannot. "Wow, who cares?" Good question -- Unfortunately, the virtio-win floppy disk images that Red Hat/Fedora ship require a 2.88MB drive, so if you forgot to insert them at boot, you'd have to change your VM configuration and try again. For a one-shot operation, that's kind of obnoxious -- it'd be nice to allow one to just insert the diskette on-demand. "OK, What are you changing in this decades-old device?" (1) Add a new property to allow users to specify what kind of drive they want without relying on magical guessing behavior. Choices are: 120, 144, 288, auto, and none. 120, 144 and 288 refer to 1.20MB, 1.44MB, and 2.88MB drives. auto refers to the auto-detect behavior QEMU currently has. none ... hides the drive. You probably don't want to use this, but it's there if you feel like creating a drive you can't use. (2) Add a new "fallback" property for use with the "auto" drive type that allows us to specify the backup behavior, too. In most cases this property won't be needed, but it is provided for allowing QEMU to be fully backwards compatible. (3) Add the concept of physical diskette size to QEMU, classifying 120-style diskettes as fundamentally different from 144 and 288 ones. (4) Revamp the automatic guessing heuristic to understand that 2.88MB style drives can accept 1.44MB diskettes. (5) Change the automatic fallback type for the automatic guessing heuristic from 1.44MB to 2.88MB for 2.6 machines and beyond, leaving 2.5- machines set to default to auto/144. (6) A lot of code cleanup in general. "Won't this break everything, you madman?" No: I tested this in MS-DOS 6.22, Fedora 23 and Windows 8.1. All seemed perfectly happy with 2.88MB drives as the default for 1.44 or 2.88MB floppy diskette images. And: Older machine types will happily still default to the 1.44 type just like they used to, so really nothing should change at all for most guests. If there ARE any guests affected in 2.6+ machine types, you are urged to use an explicit drive type that matches your application if the automatic behavior is unsuitable. === v4: === Hopefully a more logical patch order with smaller changes. 001/12:[----] [--] 'fdc: move pick_geometry' 002/12:[down] 'fdc: reduce number of pick_geometry arguments' 003/12:[down] 'fdc: add drive type qapi enum' 004/12:[0008] [FC] 'fdc: add disk field' 005/12:[down] 'fdc: Throw an assertion on misconfigured fd_formats table' 006/12:[down] 'fdc: add pick_drive' 007/12:[0018] [FC] 'fdc: Add fallback option' 008/12:[down] 'fdc: add drive type option' 009/12:[----] [-C] 'fdc: add physical disk sizes' 010/12:[0014] [FC] 'fdc: rework pick_geometry' 011/12:[----] [--] 'qtest/fdc: Support for 2.88MB drives' 012/12:[0010] [FC] 'fdc: change auto fallback drive for ISA FDC to 288' 02: Kept both debug printfs in fd_revalidate. 03: New patch, QAPI enumeration change only. 04: Re-ordered FDrive fields Fallout from 03. 05: New patch. 06: Almost completely re-done. 07: Added media_validated property Fallout from patch re-ordering. 08: Re-ordered. 10: Changed return type of pick_geometry to int. Changed one error pathway to abort, as it's not a run-time problem. 12: Rebased on top of current master. === v3: === 001/11:[----] [--] 'fdc: move pick_geometry' 002/11:[----] [--] 'fdc: refactor pick_geometry' 003/11:[----] [--] 'fdc: add disk field' 004/11:[0037] [FC] 'fdc: add default drive type option' 005/11:[down] 'fdc: Add fallback option' 006/11:[----] [-C] 'fdc: do not call revalidate on eject' 007/11:[0030] [FC] 'fdc: implement new drive type property' 008/11:[----] [-C] 'fdc: add physical disk sizes' 009/11:[0018] [FC] 'fdc: rework pick_geometry' 010/11:[----] [--] 'qtest/fdc: Support for 2.88MB drives' 011/11:[down] 'fdc: change auto fallback drive for ISA FDC to 288' 04: Remove typeA/typeB members of FDCtrl. Store e.g. -fdtypeA options directly into FDCtrl.drives[x].drive instead. 05: Add a new fallback= option that controls fdtype{A,B}=auto behavior. 07: replace get_default_drive_type which is no longer needed add get_fallback_drive_type. 09: Reworked the auto/fallback section of pick_geometry. ________________________________________________________________________________ For convenience, this branch is available at: https://github.com/jnsnow/qemu.git branch fdc-default https://github.com/jnsnow/qemu/tree/fdc-default This version is tagged fdc-default-v4: https://github.com/jnsnow/qemu/releases/tag/fdc-default-v4 John Snow (12): fdc: move pick_geometry fdc: reduce number of pick_geometry arguments fdc: add drive type qapi enum fdc: add disk field fdc: Throw an assertion on misconfigured fd_formats table fdc: add pick_drive fdc: Add fallback option fdc: add drive type option fdc: add physical disk sizes fdc: rework pick_geometry qtest/fdc: Support for 2.88MB drives fdc: change auto fallback drive for ISA FDC to 288 hw/block/fdc.c | 315 +++++++++++++++++++++++++++++-------------- hw/core/qdev-properties.c | 11 ++ hw/i386/pc.c | 17 +-- include/hw/block/fdc.h | 9 +- include/hw/compat.h | 4 + include/hw/qdev-properties.h | 1 + qapi/block.json | 16 +++ tests/fdc-test.c | 2 +- 8 files changed, 259 insertions(+), 116 deletions(-)
should we recreate ACPI tables after geometry switch? This would be especially interesting for the case of Win2k12 (or Win8.1 if you prefer) under OVMF. Den
