Re: [RFC PATCH 2/2] kvm/kvm-all.c: listener should delay kvm_vm_ioctl to the commit phase

[Emanuele Giuseppe Esposito]

Am 26/08/2022 um 16:15 schrieb David Hildenbrand:
> On 16.08.22 12:12, Emanuele Giuseppe Esposito wrote:
>> Instead of sending a single ioctl every time ->region_* or ->log_*
>> callbacks are called, "queue" all memory regions in a list that will
>> be emptied only when committing.
>>
> 
> Out of interest, how many such regions does the ioctl support? As many
> as KVM theoretically supports? (32k IIRC)
> 

I assume you mean for the new ioctl, but yes that's a good question.

The problem here is that we could have more than a single update per
memory region. So we are not limited anymore to the number of regions,
but the number of operations * number of region.

I was thinking, maybe when pre-processing QEMU could divide a single
transaction into multiple atomic operations (ie operations on the same
memory region)? That way avoid sending a single ioctl with 32k *
#operation elements. Is that what you mean?

Emanuele