RE: [Xen-ia64-devel] cset 8690 blk driver regression

RE: [Xen-ia64-devel] cset 8690 blk driver regression

[Magenheimer, Dan (HP Labs Fort Collins)]

I can confirm this is broken on ia64 and that with this
reverted, with the xenlinux/ia64 subarch changes (just
checked in by Christian) and with the set_pfn_from_mfn
patch I posted an hour ago, Xen/ia64 is ready for 3.0.1.
(Assuming of course something else doesn't get broken
between now and then :-)

So... we need to get this fixed prior to 3.0.1!

To fix it so that it works on x86 (shadow and non-shadow)
and ia64, perhaps a macro call could be substituted for
the three removed lines and define'd differently for each
arch in asm/shadow.h?

Thanks,
Dan

> -----Original Message-----
> From: xen-ia64-devel-bounces@lists.xensource.com 
> [mailto:xen-ia64-devel-bounces@lists.xensource.com] On Behalf 
> Of Williamson, Alex (Linux Kernel Dev)
> Sent: Monday, January 30, 2006 2:08 PM
> To: sos22@cam.ac.uk
> Cc: xen-devel@lists.xensource.com; xen-ia64-devel@lists.xensource.com
> Subject: [Xen-ia64-devel] cset 8690 blk driver regression
> 
> Hi Steven,
> 
>   I'm seeing a regression on ia64 with this chunk of cset 8690:
> 
> --- a/xen/common/grant_table.c	Fri Jan 27 20:38:55 2006
> +++ b/xen/common/grant_table.c	Fri Jan 27 20:57:07 2006
> @@ -522,9 +522,7 @@
>          ASSERT(d->grant_table != NULL);
>          (void)put_user(GNTST_okay, &uop->status);
>          for ( i = 0; i < op.nr_frames; i++ ) {
> -            mfn = gnttab_shared_mfn(d, d->grant_table, i);
> -            if (shadow_mode_translate(d))
> -                mfn = __mfn_to_gpfn(d, mfn);
> +            mfn = __mfn_to_gpfn(d, gnttab_shared_mfn(d, 
> d->grant_table, i));
>              (void)put_user(mfn, &op.frame_list[i]);
>          }
>      }
> 
> With this chunk, my domU no longer finds it's block device 
> and fails to
> boot:
> 
> VFS: Cannot open root device "hda1" or unknown-block(0,0)
> Please append a correct "root=" boot option
> Kernel panic - not syncing: VFS: Unable to mount root fs on
> unknown-block(0,0)
> 
> Everything appears fine if I revert it.  Is this an 
> intentional change?
> It appears to be more of a functional change than the check-in comment
> for this changeset would imply.  Thanks,
> 
> 	Alex
> 
> -- 
> Alex Williamson                             HP Linux & Open Source Lab
> 
> 
> _______________________________________________
> Xen-ia64-devel mailing list
> Xen-ia64-devel@lists.xensource.com
> http://lists.xensource.com/xen-ia64-devel
> 

RE: [Xen-ia64-devel] cset 8690 blk driver regression

[Magenheimer, Dan (HP Labs Fort Collins)]

These were two separate bugs.  Backing out
(or otherwise rewriting) that patch is still
necessary for domU to boot on ia64.

A gnttab_shared_gpfn macro sounds good to me!
(assuming defined to the pre-patch lines for
ia64 and the post-patch lines for x86?)

Thanks,
Dan

> -----Original Message-----
> From: Keir Fraser [mailto:Keir.Fraser@cl.cam.ac.uk] 
> Sent: Tuesday, January 31, 2006 3:33 PM
> To: Magenheimer, Dan (HP Labs Fort Collins)
> Cc: Williamson, Alex (Linux Kernel Dev); 
> xen-ia64-devel@lists.xensource.com; 
> xen-devel@lists.xensource.com; sos22@cam.ac.uk
> Subject: Re: [Xen-ia64-devel] cset 8690 blk driver regression
> 
> 
> On 31 Jan 2006, at 20:11, Magenheimer, Dan (HP Labs Fort 
> Collins) wrote:
> 
> > To fix it so that it works on x86 (shadow and non-shadow)
> > and ia64, perhaps a macro call could be substituted for
> > the three removed lines and define'd differently for each
> > arch in asm/shadow.h?
> 
> I removed the dummy definition of __mfn_to_gpfn() from xen/shadow.h 
> that was hiding ia64's own definition. I think Alex Williamson posted 
> that as a fix. Is using that macro here not applicable for 
> ia64 at all? 
> If not and the tree is still broken for ia64 then we can 
> perhaps define 
> a gnttab_shared_gpfn() macro.
> 
>   -- Keir
> 
> 

RE: [Xen-ia64-devel] cset 8690 blk driver regression

[Alex Williamson]

On Tue, 2006-01-31 at 14:48 -0800, Magenheimer, Dan (HP Labs Fort
Collins) wrote:
> These were two separate bugs.  Backing out
> (or otherwise rewriting) that patch is still
> necessary for domU to boot on ia64.
> 
> A gnttab_shared_gpfn macro sounds good to me!
> (assuming defined to the pre-patch lines for
> ia64 and the post-patch lines for x86?)

   The easiest thing would be making __mfn_to_gpfn() be a pass through
like below.  It works for now, but I don't know what I'm breaking by
doing this.  Thanks,

	Alex

diff -r 9ef5f0ec9df8 xen/include/asm-ia64/mm.h
--- a/xen/include/asm-ia64/mm.h Tue Jan 31 17:39:35 2006
+++ b/xen/include/asm-ia64/mm.h Tue Jan 31 10:07:45 2006
@@ -422,8 +422,7 @@
 * here. However if it's allocated by HV, we should access it directly
 */
 
-#define __mfn_to_gpfn(_d, mfn)                 \
-    machine_to_phys_mapping[(mfn)]
+#define __mfn_to_gpfn(_d, mfn)  (mfn)
 
 #define __gpfn_to_mfn(_d, gpfn)                        \
     __gpfn_to_mfn_foreign((_d), (gpfn))


-- 
Alex Williamson                             HP Linux & Open Source Lab

Re: [Xen-ia64-devel] cset 8690 blk driver regression

[Keir Fraser]

On 31 Jan 2006, at 23:08, Alex Williamson wrote:

>> These were two separate bugs.  Backing out
>> (or otherwise rewriting) that patch is still
>> necessary for domU to boot on ia64.
>>
>> A gnttab_shared_gpfn macro sounds good to me!
>> (assuming defined to the pre-patch lines for
>> ia64 and the post-patch lines for x86?)
>
>    The easiest thing would be making __mfn_to_gpfn() be a pass through
> like below.  It works for now, but I don't know what I'm breaking by
> doing this.  Thanks,

Yeah, that's probably bad news. gnttab_shared_gpfn sounds better.

  -- Keir