Gentle ping. Sam
> On 8 Jul 2019, at 20:30, Sam Eiderman <shmuel.eider...@oracle.com> wrote: > > Thanks Gerd, > > Gentle ping on this. > > Sam > >> On 1 Jul 2019, at 10:41, Gerd Hoffmann <kra...@redhat.com> wrote: >> >> On Wed, Jun 26, 2019 at 03:39:40PM +0300, Sam Eiderman wrote: >>> v1: >>> >>> Non-standard logical geometries break under QEMU. >>> >>> A virtual disk which contains an operating system which depends on >>> logical geometries (consistent values being reported from BIOS INT13 >>> AH=08) will most likely break under QEMU/SeaBIOS if it has non-standard >>> logical geometries - for example 56 SPT (sectors per track). >>> No matter what QEMU will guess - SeaBIOS, for large enough disks - will >>> use LBA translation, which will report 63 SPT instead. >>> >>> In addition we can not enforce SeaBIOS to rely on phyiscal geometries at >>> all. A virtio-blk-pci virtual disk with 255 phyiscal heads can not >>> report more than 16 physical heads when moved to an IDE controller, the >>> ATA spec allows a maximum of 16 heads - this is an artifact of >>> virtualization. >>> >>> By supplying the logical geometies directly we are able to support such >>> "exotic" disks. >>> >>> We will use fw_cfg to do just that. >>> >>> v2: >>> >>> Fix missing parenthesis check in >>> "hd-geo-test: Add tests for lchs override" >>> >>> v3: >>> >>> * Rename fw_cfg key to "bios-geometry". >>> * Remove "extendible" interface. >>> * Add cpu_to_le32 fix as Laszlo suggested or big endian hosts >>> * Fix last qtest commit - automatic docker tester for some reason does not >>> have qemu-img set >>> >>> v4: >>> >>> * Change fw_cfg interface from mixed textual/binary to textual only >>> >>> v5: >>> >>> * Fix line > 80 chars in tests/hd-geo-test.c >> >> Reviewed-by: Gerd Hoffmann <kra...@redhat.com> >> >> cheers, >> Gerd >> >
