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[PULL v2 7/8] bootdevice: FW_CFG interface for LCHS values
From: |
John Snow |
Subject: |
[PULL v2 7/8] bootdevice: FW_CFG interface for LCHS values |
Date: |
Thu, 3 Oct 2019 15:32:44 -0400 |
From: Sam Eiderman <address@hidden>
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 <address@hidden>
Reviewed-by: Arbel Moshe <address@hidden>
Signed-off-by: Sam Eiderman <address@hidden>
Message-id: address@hidden
Signed-off-by: John Snow <address@hidden>
---
include/sysemu/sysemu.h | 1 +
bootdevice.c | 32 ++++++++++++++++++++++++++++++++
hw/nvram/fw_cfg.c | 14 +++++++++++---
3 files changed, 44 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 2b12fb85a4..b034ad7bdc 100644
--- a/bootdevice.c
+++ b/bootdevice.c
@@ -405,3 +405,35 @@ void del_boot_device_lchs(DeviceState *dev, const char
*suffix)
}
}
}
+
+/* Serialized as: (device name\0 + lchs struct) x devices */
+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 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)
--
2.21.0
- [PULL v2 0/8] Ide patches, John Snow, 2019/10/03
- [PULL v2 1/8] block: Refactor macros - fix tabbing, John Snow, 2019/10/03
- [PULL v2 2/8] block: Support providing LCHS from user, John Snow, 2019/10/03
- [PULL v2 3/8] bootdevice: Add interface to gather LCHS, John Snow, 2019/10/03
- [PULL v2 4/8] scsi: Propagate unrealize() callback to scsi-hd, John Snow, 2019/10/03
- [PULL v2 5/8] bootdevice: Gather LCHS from all relevant devices, John Snow, 2019/10/03
- [PULL v2 6/8] bootdevice: Refactor get_boot_devices_list, John Snow, 2019/10/03
- [PULL v2 7/8] bootdevice: FW_CFG interface for LCHS values,
John Snow <=
- [PULL v2 8/8] hd-geo-test: Add tests for lchs override, John Snow, 2019/10/03
- Re: [PULL v2 0/8] Ide patches, no-reply, 2019/10/03
- Re: [PULL v2 0/8] Ide patches, Peter Maydell, 2019/10/07