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| author | Sam Eiderman | 2019-10-16 18:41:44 +0200 |
|---|---|---|
| committer | John Snow | 2019-10-31 16:47:38 +0100 |
| commit | aea60a13b9d43bb4c5748a1216af954a0e9d22d4 (patch) | |
| tree | 8b8a8e2439331639633636a48136604f9dc65720 /include/sysemu | |
| parent | bootdevice: Refactor get_boot_devices_list (diff) | |
| download | qemu-aea60a13b9d43bb4c5748a1216af954a0e9d22d4.tar.gz qemu-aea60a13b9d43bb4c5748a1216af954a0e9d22d4.tar.xz qemu-aea60a13b9d43bb4c5748a1216af954a0e9d22d4.zip | |
bootdevice: FW_CFG interface for LCHS values
Using fw_cfg, supply logical CHS values directly from QEMU to the BIOS.
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 report - SeaBIOS, for large enough disks - will
use LBA translation, which will report 63 SPT instead.
In addition we cannot force SeaBIOS to rely on physical geometries at
all. A virtio-blk-pci virtual disk with 255 phyiscal heads cannot
report more than 16 physical heads when moved to an IDE controller,
since the ATA spec allows a maximum of 16 heads - this is an artifact of
virtualization.
By supplying the logical geometries directly we are able to support such
"exotic" disks.
We serialize this information in a similar way to the "bootorder"
interface.
The new fw_cfg entry is "bios-geometry".
Reviewed-by: Karl Heubaum <karl.heubaum@oracle.com>
Reviewed-by: Arbel Moshe <arbel.moshe@oracle.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Sam Eiderman <shmuel.eiderman@oracle.com>
Signed-off-by: Sam Eiderman <sameid@google.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Diffstat (limited to 'include/sysemu')
| -rw-r--r-- | include/sysemu/sysemu.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h index 5bc5c79cbc..80c57fdc4e 100644 --- a/include/sysemu/sysemu.h +++ b/include/sysemu/sysemu.h @@ -106,6 +106,7 @@ void validate_bootdevices(const char *devices, Error **errp); void add_boot_device_lchs(DeviceState *dev, const char *suffix, uint32_t lcyls, uint32_t lheads, uint32_t lsecs); void del_boot_device_lchs(DeviceState *dev, const char *suffix); +char *get_boot_devices_lchs_list(size_t *size); /* handler to set the boot_device order for a specific type of MachineClass */ typedef void QEMUBootSetHandler(void *opaque, const char *boot_order, |