[libvirt] [PULL 8/9] bootdevice: FW_CFG interface for LCHS values
From: Sam Eiderman <shmuel.eiderman(a)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(a)oracle.com>
Reviewed-by: Arbel Moshe <arbel.moshe(a)oracle.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd(a)redhat.com>
Signed-off-by: Sam Eiderman <shmuel.eiderman(a)oracle.com>
Signed-off-by: Sam Eiderman <sameid(a)google.com>
Tested-by: Philippe Mathieu-Daudé <philmd(a)redhat.com>
Signed-off-by: John Snow <jsnow(a)redhat.com>
---
include/sysemu/sysemu.h | 1 +
bootdevice.c | 31 +++++++++++++++++++++++++++++++
hw/nvram/fw_cfg.c | 14 +++++++++++---
3 files changed, 43 insertions(+), 3 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,
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);
+ }
+
+ *size = total;
+
+ return list;
+}
diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
index aef1727250..44a3c19326 100644
--- a/hw/nvram/fw_cfg.c
+++ b/hw/nvram/fw_cfg.c
@@ -949,13 +949,21 @@ 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)
--
2.21.0