From: Nicolin Chen nicolinc@nvidia.com Sent: Saturday, January 25, 2025 8:31 AM
+/*
- An iommufd_veventq object represents an interface to deliver vIOMMU
events to
- the user space. It is created/destroyed by the user space and associated
with
- vIOMMU object(s) during the allocations.
s/object(s)/object/, given the eventq cannot be shared between vIOMMUs.
+static inline void iommufd_vevent_handler(struct iommufd_veventq *veventq,
struct iommufd_vevent *vevent)+{
- struct iommufd_eventq *eventq = &veventq->common;
- /*
* Remove the overflow node and add the new node at the sametime. Note
* it is possible that vevent == &veventq->overflow for sequenceupdate
*/- spin_lock(&eventq->lock);
- if (veventq->overflow.on_list) {
list_del(&veventq->overflow.node);veventq->overflow.on_list = false;- }
We can save one field 'on_list' in every entry by:
if (list_is_last(&veventq->overflow.node, &eventq->deliver)) list_del(&veventq->overflow.node);
+/**
- struct iommufd_vevent_header - Virtual Event Header for a vEVENTQ
Status
- @flags: Combination of enum iommu_veventq_flag
- @sequence: The sequence index of a vEVENT in the vEVENTQ, with a
range of
[0, INT_MAX] where the following index of INT_MAX is 0
- @__reserved: Must be 0
- Each iommufd_vevent_header reports a sequence index of the following
vEVENT:
- || header0 {sequence=0} | data0 | header1 {sequence=1} | data1 |...|
dataN ||
- And this sequence index is expected to be monotonic to the sequence
index of
- the previous vEVENT. If two adjacent sequence indexes has a delta larger
than
- 1, it indicates that an overflow occurred to the vEVENTQ and that delta - 1
- number of vEVENTs lost due to the overflow (e.g. two lost vEVENTs):
- || ... | header3 {sequence=3} | data3 | header6 {sequence=6} | data6 | ...
||
- If an overflow occurred to the tail of the vEVENTQ and there is no
following
- vEVENT providing the next sequence index, a special overflow header
would be
- added to the tail of the vEVENTQ, where there would be no more type-
specific
- data following the vEVENTQ:
- ||...| header3 {sequence=3} | data4 | header4 {flags=OVERFLOW,
sequence=4} ||
- */
+struct iommufd_vevent_header {
- __aligned_u64 flags;
- __u32 sequence;
- __u32 __reserved;
+};
Is there a reason that flags must be u64? At a glance all flags fields (except the one in iommu_hwpt_vtd_s1) in iommufd uAPIs are u32 which can cut the size of the header by half...
+void iommufd_veventq_abort(struct iommufd_object *obj) +{
- struct iommufd_eventq *eventq =
container_of(obj, struct iommufd_eventq, obj);- struct iommufd_veventq *veventq = eventq_to_veventq(eventq);
- struct iommufd_viommu *viommu = veventq->viommu;
- struct iommufd_vevent *cur, *next;
- lockdep_assert_held_write(&viommu->veventqs_rwsem);
- list_for_each_entry_safe(cur, next, &eventq->deliver, node) {
list_del(&cur->node);kfree(cur);
kfree() doesn't apply to the overflow node.
otherwise it looks good to me:
Reviewed-by: Kevin Tian kevin.tian@intel.com