[Qemu-devel] Re: sparc solaris guest, hsfs_putpage: dirty HSFS page

[Artyom Tarasenko <atar4qemu@googlemail.com>]

2010/1/24 Blue Swirl <blauwirbel@gmail.com>:
> On Sun, Jan 24, 2010 at 2:02 AM, Artyom Tarasenko
> <atar4qemu@googlemail.com> wrote:
>> All solaris versions which currently boot (from cd) regularly produce buckets of
>> "hsfs_putpage: dirty HSFS page" messages.
>>
>> High Sierra is a pretty old and stable stuff, so it is possible that
>> the code is similar to OpenSolaris.
>> I looked in debugger, and the function calls hierarchy looks pretty similar.
>>
>> Now in the OpenSolaris source code there is a nice comment:
>> http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/uts/common/fs/hsfs/hsfs_vnops.c#1758
>> /*
>> * Normally pvn_getdirty() should return 0, which
>> * impies that it has done the job for us.
>> * The shouldn't-happen scenario is when it returns 1.
>> * This means that the page has been modified and
>> * needs to be put back.
>> * Since we can't write on a CD, we fake a failed
>> * I/O and force pvn_write_done() to destroy the page.
>> */
>> if (pvn_getdirty(pp, flags) == 1) {
>>                cmn_err(CE_NOTE,
>>                            "hsfs_putpage: dirty HSFS page");
>>
>> Now the question: does the problem have to do with qemu caches (non-)emulation?
>> Can it be that we mark non-dirty pages dirty? Or does qemu always mark
>> pages dirty exactly to avoid cache emulation?
>>
>> Otherwise it means something else goes astray and Solaris guest really
>> modifies the pages it shouldn't.
>>
>> Just wonder what to dig first, MMU or IRQ emulation (the two most
>> obvious suspects).
>
> Maybe the stores via MMU bypass ASIs

why bypass stores? What about the non-bypass ones?

> should use
> st[bwlq]_phys_notdirty.

Seems that st[bw]_phys_notdirty are not implemeted yet?

I've changed [lq] for asi 0x20 and 21-2f and see no difference. Also I
put some debug printfs and see that none of these ASIs is called after
the Solaris kernel is loaded.

> It can break display handling, though.


-- 
Regards,
Artyom Tarasenko

solaris/sparc under qemu blog: http://tyom.blogspot.com/