On 2023/7/12 17:45, Jean-Philippe Brucker wrote:
On Wed, Jul 12, 2023 at 10:32:13AM +0800, Baolu Lu wrote:
btw is there value of moving the group handling logic from
iommu_queue_iopf() to this common function?
I wonder whether there is any correctness issue if not forwarding
partial request to iommufd. If not this can also help reduce
notifications to the user until the group is ready.
I don't think there's any correctness issue. But it should be better if
we can inject the page faults to vm guests as soon as possible. There's
no requirement to put page requests to vIOMMU's hardware page request
queue at the granularity of a fault group. Thoughts?
Not sure I understand you correctly, but we can't inject partial fault
groups: if the HW PRI queue overflows, the last fault in a group may be
lost, so the non-last faults in that group already injected won't be
completed (until PRGI reuse), leaking PRI request credits and guest
resources.
Yeah, that's how vIOMMU injects the faults. On host/hypervisor side, my
understanding is that faults should be uploaded as soon as possible.
Best regards,
baolu
