On Fri, May 30, 2025 at 02:40:37PM -0300, Jason Gunthorpe wrote:
On Fri, May 30, 2025 at 10:38:24AM -0700, Nicolin Chen wrote:
On Fri, May 30, 2025 at 01:14:55PM -0300, Jason Gunthorpe wrote:
On Sat, May 17, 2025 at 08:21:31PM -0700, Nicolin Chen wrote:
- offset =
cmd->nesting_parent_iova - PAGE_ALIGN(cmd->nesting_parent_iova);- max_npages = DIV_ROUND_UP(offset + cmd->length, PAGE_SIZE);
This should probably be capped to PAGE_SIZE/sizeof(void *), return EINVAL if not
Hmm, mind elaborating where this PAGE_SIZE/sizeof comes from?
We can usually allocate up to a PAGE_SIZE without too much trouble. Beyond that it gets more likely to fail.
If PAGE_SIZE=4096, the upper limit for max_npages is 512, i.e. the max size of a guest queue is 2MB? It seems to be too small, as the VMM can use a larger huge page size to back the guest queue?
- hw_queue->viommu = viommu;
- refcount_inc(&viommu->obj.users);
- hw_queue->length = cmd->length;
- hw_queue->base_addr = cmd->nesting_parent_iova;
When the driver is running, which can be a source of bugs.
Hmm, I don't quite follow the "bugs" here. Any example?
Like if the driver thinks that hw_queue->length should be valid during init, it turns out it isn't.
Ah, I see. Yes.
Nicolin