| Message ID | 20120729002647.GA19206@comcast.net |
|---|---|
| State | New |
| Headers | show |
Matthew Ogilvie <mmogilvi_qemu@miniinfo.net> writes: > On Sat, Jul 28, 2012 at 08:33:54AM +0200, Markus Armbruster wrote: >> Matthew Ogilvie <mmogilvi_qemu@miniinfo.net> writes: > [...] >> > 1. It doesn't seem to recognize the hard drive geometry, even >> > if I use "-hdachs" and keep it carefully inside ancient >> > limitations. Note that at the time, hard drives did not support >> > self-identification commands for the geometry; you had to >> > configure it in BIOS. I also have some old notes from when my >> > dad was asking Microport about compatibility; apparently >> > they wanted to know the specific BIOS version in order to >> > decide about compatibility. Maybe UNIX is bypassing later >> > standards for looking up geometry, and trying to get it in >> > some non-standard way (straight from CMOS or something?) >> >> Please run QEMU with -trace events=trace-events, where trace-events is a >> file containing the line "hd_geometry_*". Post results, along with your >> full command line. >> >> [...] > > Thanks for the suggestion. I've narrowed down a couple of problems > based on it: > > First, the -hdachs command line option is silently ignored depending > on its relative order compared to other command line options. I've > attached a patch below. Recommend to post patches with Subject: [PATCH] ..., so that maintainers spot them. > ---- > > Second, this UNIX kernel and/or bootloader always seems to think > it has 17 sectors per track, no matter what I tell qemu (using a blank > image; no partition table). But UNIX does recognize the number > of cylinders and heads correctly, and I've verified that > the number of sectors per track is also correct in the fixed disk > parameter table, by using the monitor's "x" (examine) command. > > Potentially guess_chs_for_size() could be enhanced to return 17 > for small drive images when appropriate, to be consistent with most > legacy drives having 17. Or maybe there is some more > obscure way to get UNIX to recognize non-17 sectors. > Or either document a third party way to put a basic partition table > on a new image, or add that ability to qemu-img, so that code > like that in guess_disk_lchs() or similar code that might exist > in some operating systems would have something to work with. > I also found a 1988 posting that suggests some leads for > further investigation: > http://www.megalextoria.com/usenet-archive/news076f1/b96/comp/unix/microport/00000798.html > > But I'm not really inclined to worry much more about this > right now, because I have a usable workaround: Always define > my disk image size to be consistent with 17 sectors per > track, and tell qemu to use 17. Yes, that's best. > ---- > > (Now if I can just figure out what's up with the sporadic panic > in UNIX's interrupt handlers...) > > ---- > > From: Matthew Ogilvie <mmogilvi_qemu@miniinfo.net> > Date: Sat, 28 Jul 2012 17:01:14 -0600 > Subject: [PATCH] vl.c: fix -hdachs/-hda argument order parsing issues > > Without this patch, the -hdachs argument had to occur either > BEFORE the corresponding "-hda" option, or AFTER the plain > disk image name (if neither -hda nor -drive is used). Otherwise > it would effectively be ignored. > > Option -hdachs still has no effect on -drive, but that seems > reasonable. Pretty sure it's intentional. > Signed-off-by: Matthew Ogilvie <mmogilvi_qemu@miniinfo.net> > --- > vl.c | 15 +++++++++++++-- > 1 file changed, 13 insertions(+), 2 deletions(-) > > diff --git a/vl.c b/vl.c > index c18bb80..e0611eb 100644 > --- a/vl.c > +++ b/vl.c > @@ -2374,7 +2374,18 @@ int main(int argc, char **argv, char **envp) > if (optind >= argc) > break; > if (argv[optind][0] != '-') { > - hda_opts = drive_add(IF_DEFAULT, 0, argv[optind++], HD_OPTS); > + char buf[256]; > + if (cyls == 0) > + snprintf(buf, sizeof(buf), "%s", HD_OPTS); > + else > + snprintf(buf, sizeof(buf), > + "%s,cyls=%d,heads=%d,secs=%d%s", > + HD_OPTS , cyls, heads, secs, > + translation == BIOS_ATA_TRANSLATION_LBA ? > + ",trans=lba" : > + translation == BIOS_ATA_TRANSLATION_NONE ? > + ",trans=none" : ""); > + hda_opts = drive_add(IF_DEFAULT, 0, argv[optind++], buf); > } else { > const QEMUOption *popt; > I suspect this was broken in commit e4bcb14c, Dec 2007. Makes me doubt -hdachs is used much. Duplicates the code under case QEMU_OPTION_hda. Should be factored out. > @@ -2404,7 +2415,7 @@ int main(int argc, char **argv, char **envp) > ",trans=lba" : > translation == BIOS_ATA_TRANSLATION_NONE ? > ",trans=none" : ""); > - drive_add(IF_DEFAULT, 0, optarg, buf); > + hda_opts = drive_add(IF_DEFAULT, 0, optarg, buf); > break; > } > case QEMU_OPTION_hdb: This part fixes up commit 5645b0f4.
diff --git a/vl.c b/vl.c index c18bb80..e0611eb 100644 --- a/vl.c +++ b/vl.c @@ -2374,7 +2374,18 @@ int main(int argc, char **argv, char **envp) if (optind >= argc) break; if (argv[optind][0] != '-') { - hda_opts = drive_add(IF_DEFAULT, 0, argv[optind++], HD_OPTS); + char buf[256]; + if (cyls == 0) + snprintf(buf, sizeof(buf), "%s", HD_OPTS); + else + snprintf(buf, sizeof(buf), + "%s,cyls=%d,heads=%d,secs=%d%s", + HD_OPTS , cyls, heads, secs, + translation == BIOS_ATA_TRANSLATION_LBA ? + ",trans=lba" : + translation == BIOS_ATA_TRANSLATION_NONE ? + ",trans=none" : ""); + hda_opts = drive_add(IF_DEFAULT, 0, argv[optind++], buf); } else { const QEMUOption *popt; @@ -2404,7 +2415,7 @@ int main(int argc, char **argv, char **envp) ",trans=lba" : translation == BIOS_ATA_TRANSLATION_NONE ? ",trans=none" : ""); - drive_add(IF_DEFAULT, 0, optarg, buf); + hda_opts = drive_add(IF_DEFAULT, 0, optarg, buf); break; } case QEMU_OPTION_hdb: