16 Oct
2019
16 Oct
'19
11:02 a.m.
Gentle Ping,
Philippe, John?
Just wondering if the series is okay, as Gerd pointed out this series is a blocker for the corresponding changes in SeaBIOS for v 1.13
Sam
On Tue, Oct 8, 2019 at 2:51 PM Sam Eiderman sameid@google.com wrote:
On Tue, Oct 8, 2019, 13:34 Philippe Mathieu-Daudé philmd@redhat.com wrote:
Hi Sam,
On 9/29/19 12:13 PM, Sam Eiderman wrote:
Philippe, thanks for the fast review,
Fast is not always the friend of careful.
John, thanks for picking up this hot potato :-)
Sam
On Thu, Sep 26, 2019 at 10:16 PM Philippe Mathieu-Daudé <philmd@redhat.com mailto:philmd@redhat.com> wrote:
On 9/26/19 9:09 PM, Philippe Mathieu-Daudé wrote: > On 9/26/19 8:26 PM, John Snow wrote: >> On 9/26/19 5:57 AM, Philippe Mathieu-Daudé wrote: >>> Hi Sam, >>> >>> On 9/25/19 1:06 PM, Sam Eiderman wrote: >>>> From: Sam Eiderman <shmuel.eiderman@oracle.com <mailto: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 <mailto:karl.heubaum@oracle.com>> >>>> Reviewed-by: Arbel Moshe <arbel.moshe@oracle.com <mailto:arbel.moshe@oracle.com>> >>>> Signed-off-by: Sam Eiderman <shmuel.eiderman@oracle.com <mailto:shmuel.eiderman@oracle.com>> >>>> --- >>>> bootdevice.c | 32 ++++++++++++++++++++++++++++++++ >>>> hw/nvram/fw_cfg.c | 14 +++++++++++--- >>>> include/sysemu/sysemu.h | 1 + >>>> 3 files changed, 44 insertions(+), 3 deletions(-) >>>> >>>> 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 */I suppose the lchs struct is serialized in little-endian.
Nice catch, that's just a bad comment, should be removed. There used to be a struct with 3 uint32_t values, Laszlo pointed out that there is an endianess problem (this was fixed in v3) later Kevin suggested to make it a textual interface and the struct was removed (in v4) but the comment remained.
>>>> +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);Sam. can you check if you don't need endianness conversion here?
Hmm, since this is a textual interface, I believe this should work no?
uint32_t a = 4; g_strdup_printf("%s" PRIu32, a);
Should return "4" no matter the endianess? (Taken care of by glib?)
>>> >>> Hmm maybe we can g_free(bootpath) directly here. >>> >> >> I think it's okay to do it at the bottom of the loop. No real benefit to >> being that eager to free resources in my mind. I expect setup at the top >> of a block and teardown at the bottom of a block. >> >> Trying to do too much in the middle gets messy in my opinion, not that >> it seems to matter here. > > No problem. > >>>> + >>>> + 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); >>> >>> OK. Can you add a test in tests/fw_cfg-test.c please? >>> >> >> :D >> >>>> + 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); >>> >>> Please add some documentation. At least 'size' must be non-NULL. >>> >> >> Sure; but I wasn't going to gate on it because this series went unloved >> for so long. At this point, a follow-up patch is fine. > > OK > >> >>> Ideally you should add doc for the other functions added in 3/8 >>> "bootdevice: Add interface to gather LCHS" too. >>> >> >> Same thing here. >> >>> John, what do you think about extracting the *boot_device* functions out >>> of "sysemu.h"? >>> >> >> Potentially worthwhile; but not critical at the moment. The source tree >> is not the best-organized thing as-is and I don't think it's fair to >> hold this series up for much longer for nice-to-haves, ultimately. >> >> More targeted improvements might avoid the "whose responsibility is it >> to stage this?" hot potato we played with this one; so I'd rather have >> smaller follow-up patches handled by the respective maintainers. > > Sure, fair enough. I forgot: Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com <mailto:philmd@redhat.com>>Meanwhile I withdraw my fast R-b :(
Regards,
Phil.