Re: ZFS boot problems with memory > 1MB

On Tuesday 23 February 2010 12:36:31 pm Brandon Gooch wrote:
> On Tue, Feb 23, 2010 at 10:24 AM, John Baldwin <jhb_at_freebsd.org> wrote:
> > On Tuesday 23 February 2010 10:28:49 am Brandon Gooch wrote:
> >> On Tue, Feb 23, 2010 at 7:29 AM, Andriy Gapon <avg_at_icyb.net.ua> wrote:
> >> > on 23/02/2010 13:18 Renato Botelho said the following:
> >> >> On Mon, Feb 22, 2010 at 7:35 PM, Chris Hedley
> >> >> <freebsd-current_at_chrishedley.com> wrote:
> >> > [snip]
> >> >>> Do you have USB legacy support enabled in your BIOS?  I'm not sure if
> >> >>> there's an option for the loader to use USB devices natively, but the BIOS's
> >> >>> legacy option where it provides AT/PS2 emulation is probably the easiest way
> >> >>> to get the keyboard working.
> >> >>
> >> >> Yes, I do, but it seems to be a regression on FreeBSD itself, I had this problem
> >> >> in the past and I checked the same things i need to check in the past again and
> >> >> everything is fine.
> >> >
> >> > A more precise way to state that would be "a regression in FreeBSD boot/loader".
> >> > I think that you are referring to the issue that was fixed by r189017.
> >> > It might be worthwhile investigating what was done in that revision and what
> >> > happened in sys/boot code since then.
> >> >
> >> > One possibility is that your BIOS uses memory above 1MB for USB emulation, but
> >> > doesn't mark that memory as used in system memory map.  In that case that memory
> >> > could be overwritten by the loader.  If that's true then the blame is on the BIOS.
> >> >  Alternatively, our code might be parsing the system memory map incorrectly.
> >> > But I am just making wild guesses here.
> >> >
> >>
> >> I don't know if it is at all related, but this commit has caused
> >> problems for me booting at least one of my machines:
> >>
> >> http://svn.freebsd.org/viewvc/base/head/sys/boot/i386/zfsboot/zfsboot.c?r1=199714&r2=200309
> >>
> >> Commit message:
> >>
> >> Revision 200309 - (view) (annotate) - [select for diffs]
> >> Modified Wed Dec 9 20:36:56 2009 UTC (2 months, 2 weeks ago) by jhb
> >> File length: 24893 byte(s)
> >> Diff to previous 199714
> >> - Port bios_getmem() from libi386 to {gpt,}zfsboot() and use it to
> >>   safely allocate a heap region above 1MB.  This enables {gpt,}zfsboot()
> >>   to allocate much larger buffers than before.
> >> - Use a larger buffer (1MB instead of 128K) for temporary ZFS buffers.  This
> >>   allows more reliable reading of compressed files in a raidz/raidz2 pool.
> >>
> >> Submitted by: Matt Reimer  mattjreimer of gmail
> >> MFC after:    1 week
> >
> > Starting a new thread, which problems are you seeing with this change?  ZFS is
> > a good bit more memory hungry than UFS, so it really needs to use high memory
> > for its heap.  Also, I wonder if you still have problems if you use the older
> > zfsboot with the newer zfsloader?  Finally, you need to use disklabel -B or
> > some such to update the zfsboot bits for this change to take effect.
> >
> > --
> > John Baldwin
> >
> 
> I filed a PR so it wouldn't fall through the cracks:
> 
> http://www.freebsd.org/cgi/query-pr.cgi?pr=144234
> 
> I guess I tried a combination of various revisions of bootstrap code
> and loaders when I first encountered the issue. It was when I wrote a
> recent gptzfsboot to the geom that I saw the symptoms:
> 
> error 1 lba 48
> error 1 lba 1
> No ZFS pools located, can't boot
> 
> I just wound up using sys/boot/i386/zfsboot/zfsboot.c revision 199714
> to build a working gptzfsboot on another system and wrote that to the
> disk to get the machine operational.

Try this:

Index: zfsboot.c
===================================================================
--- zfsboot.c	(revision 204207)
+++ zfsboot.c	(working copy)
_at__at_ -467,6 +467,7 _at__at_
 static inline void
 putc(int c)
 {
+    v86.ctl = 0;
     v86.addr = 0x10;
     v86.eax = 0xe00 | (c & 0xff);
     v86.ebx = 0x7;
_at__at_ -617,6 +618,8 _at__at_
     off_t off;
     struct dsk *dsk;
 
+    dmadat = (void *)(roundup2(__base + (int32_t)&_end, 0x10000) - __base);
+
     bios_getmem();
 
     if (high_heap_size > 0) {
_at__at_ -627,9 +630,6 _at__at_
 	heap_end = (char *) PTOV(bios_basemem);
     }
 
-    dmadat = (void *)(roundup2(__base + (int32_t)&_end, 0x10000) - __base);
-    v86.ctl = V86_FLAGS;
-
     dsk = malloc(sizeof(struct dsk));
     dsk->drive = *(uint8_t *)PTOV(ARGS);
     dsk->type = dsk->drive & DRV_HARD ? TYPE_AD : TYPE_FD;
_at__at_ -1157,6 +1157,7 _at__at_
      * when no such key is pressed in reality. As far as I can tell,
      * this only happens shortly after a reboot.
      */
+    v86.ctl = V86_FLAGS;
     v86.addr = 0x16;
     v86.eax = fn << 8;
     v86int();

-- 
John Baldwin