Re: [Xen-devel] Crash with paravirt-ops 2.6.31.6 kernel

["Jan Beulich" <JBeulich@xxxxxxxxxx>]

>>> Jeremy Fitzhardinge <jeremy@xxxxxxxx> 25.11.09 22:24 >>>
>On 11/25/09 02:22, Jan Beulich wrote:
>> Okay, I think I spotted the relevant difference: 2.6.18 and forward ports
>> set VGCF_in_syscall only when returning from 64-bit system calls (through
>> ret_from_sys_call) - 32-bit syscalls (regardless of the entry path taken)
>> return through int_ret_from_sys_call. 32-bit guest kernels shouldn't be
>> affected by this, as compat mode returns from the hypervisor
>> (compat_restore_all_guest) always use iret.
>>   
>
>I think dropping the VCGF_in_syscall flag is the simplest possible fix
>then.  There doesn't seem to be a huge benefit to using sysret in this
>case.  Does this look OK?

Yes, with one (more cosmetic than really useful) adjustment - the flag
should also be dropped from the !CONFIG_IA32_EMULATION code path
at the end of the file.

In any case,
Acked-by: Jan Beulich <jbeulich@xxxxxxxxxx>

Jan


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