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

[Artyom Tarasenko]

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).

-- 
Regards,
Artyom Tarasenko

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