On 10/16/19 6:41 PM, Sam Eiderman wrote:
From: Sam Eiderman shmuel.eiderman@oracle.com
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
bootdevice.c | 31 +++++++++++++++++++++++++++++++ hw/nvram/fw_cfg.c | 14 +++++++++++--- include/sysemu/sysemu.h | 1 + 3 files changed, 43 insertions(+), 3 deletions(-)
diff --git a/bootdevice.c b/bootdevice.c index 2cf6b37c57..03aaffcc8d 100644 --- a/bootdevice.c +++ b/bootdevice.c @@ -405,3 +405,34 @@ void del_boot_device_lchs(DeviceState *dev, const char *suffix) } } }
+char *get_boot_devices_lchs_list(size_t *size) +{
- FWLCHSEntry *i;
- size_t total = 0;
- char *list = NULL;
- QTAILQ_FOREACH(i, &fw_lchs, link) {
char *bootpath;char *chs_string;size_t len;bootpath = get_boot_device_path(i->dev, false, i->suffix);chs_string = g_strdup_printf("%s %" PRIu32 " %" PRIu32 " %" PRIu32,bootpath, i->lcyls, i->lheads, i->lsecs);if (total) {list[total - 1] = '\n';}len = strlen(chs_string) + 1;list = g_realloc(list, total + len);memcpy(&list[total], chs_string, len);total += len;g_free(chs_string);g_free(bootpath);- }
Hmm maybe assert(size != NULL) or if(size) {
- *size = total;
} or simply document "@size must not be NULL" in the declaration.
Can be a follow-up cleaning patch.
Regardless: Tested-by: Philippe Mathieu-Daudé philmd@redhat.com
- return list;
+} diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c index 7dc3ac378e..18aff658c0 100644 --- a/hw/nvram/fw_cfg.c +++ b/hw/nvram/fw_cfg.c @@ -920,13 +920,21 @@ void *fw_cfg_modify_file(FWCfgState *s, const char *filename,
static void fw_cfg_machine_reset(void *opaque) {
- MachineClass *mc = MACHINE_GET_CLASS(qdev_get_machine());
- FWCfgState *s = opaque; void *ptr; size_t len;
- FWCfgState *s = opaque;
- char *bootindex = get_boot_devices_list(&len);
- char *buf;
- ptr = fw_cfg_modify_file(s, "bootorder", (uint8_t *)bootindex, len);
buf = get_boot_devices_list(&len);
ptr = fw_cfg_modify_file(s, "bootorder", (uint8_t *)buf, len); g_free(ptr);
if (!mc->legacy_fw_cfg_order) {
buf = get_boot_devices_lchs_list(&len);ptr = fw_cfg_modify_file(s, "bios-geometry", (uint8_t *)buf, len);g_free(ptr);} }
static void fw_cfg_machine_ready(struct Notifier *n, void *data)
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,
Tested-by: Philippe Mathieu-Daudé philmd@redhat.com