Re: [Qemu-devel] Re: strange crash on FreeBSD-current/amd64 (pointer truncation?)

[Gwenole Beauchesne]

Hi,

> Hmm.  All I can say is the upper half of rbx (which holds T0) gets
> spilled on FreeBSD-current/amd64 hosts unless saving and restoring
> the full 64 bit of it...

That's also what I got with VirtualBox on x86_64. Here is an update to  
the patch I posted yesterday and that applies to current QEMU CVS  
instead.

Please note this one applies unconditionnally of the host and target  
combinations. Besides, I only tested the following combinations:  
x86_64/x86_64-softmmu, x86_64/i386-softmmu, i586/x86_64-softmmu,  
i586/i386-softmmu. And I verified that the generated code for  
cpu_exec() with both gcc 3.4 and gcc 4.1 actually does the host  
registers save/restore correctly.

BTW, for e.g. SPARC hosts with %l<R> registers, we could define  
something like DONT_PRESERVE_AREG<AR> since those would lay in a new  
register window and thus don't require an explicit save/restore.

Regards,
Gwenole Beauchesne

<http://svn.mandriva.com/cgi-bin/viewvc.cgi/packages/cooker/qemu/ 
current/SOURCES/qemu-0.8.3-preserve-host-registers.patch>

qemu-0.8.3-preserve-host-registers.patch
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