Am 17.07.2019 um 21:03 hat Sam Eiderman geschrieben: > Gentle ping. Through which tree is this supposed to go? I feel this is more firmware interface related than block layer stuff.
Kevin > > 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 > >> > > >
