On Tue, Oct 8, 2019, 13:34 Philippe Mathieu-Daudé <phi...@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 > > <phi...@redhat.com <mailto:phi...@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.eider...@oracle.com > > <mailto:shmuel.eider...@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.heub...@oracle.com > > <mailto:karl.heub...@oracle.com>> > > >>>> Reviewed-by: Arbel Moshe <arbel.mo...@oracle.com > > <mailto:arbel.mo...@oracle.com>> > > >>>> Signed-off-by: Sam Eiderman <shmuel.eider...@oracle.com > > <mailto:shmuel.eider...@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 <phi...@redhat.com > > <mailto:phi...@redhat.com>> > > Meanwhile I withdraw my fast R-b :( > > Regards, > > Phil. >
