Christian Ehrhardt wrote:
There already exists a loop which does this, see
make_all_cpus_request(). It uses an IPI (Marcelo, can't it use the
reschedule interrupt?). It has a couple of optimizations -- if the
request is already set, it skips the IPI, and it avoids the IPI for
vcpus out of guest mode. Maybe it could fit s390 too.
I assume that the IPI on x86 is a implicit consequence of the
smp_call_function_many function,
Yes. It's only used to exit the guest, the IPI itself does nothing.
but I think this doesn't work that way for us. The kick implied by
that call would be recieved, but not reach the code the checke
vcpu->request.
vcpu->requests is not checked by the IPI. Instead, it is checked just
before entering guest mode, with interrupts disabled.
If the request is made before the check, no IPI is made, and the check
finds the bit set.
If the request is made after the check, an IPI is made, and the guest
exits immediately after entry.
I could add that behaviour, but that could make our normal interrupt
handling much slower. Therefore I don't want to call that function,
but on the other hand I like the "skip if the request is already set"
functionality and think about adding that in my loop.
I don't understand why it would affect your interrupt handling. We need
someone that talks both x86 and s390 to break the language barrier...
I'll apply the patches, but please do look further into increasing
commonality.
--
error compiling committee.c: too many arguments to function
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