Messages in this thread | | | Date | Tue, 28 Jun 2022 17:10:11 +0800 | Subject | Re: [PATCH v9 10/11] iommu: Per-domain I/O page fault handling | From | Ethan Zhao <> |
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Hi, Baolu
在 2022/6/28 14:28, Baolu Lu 写道: > Hi Ethan, > > On 2022/6/27 21:03, Ethan Zhao wrote: >> Hi, >> >> 在 2022/6/21 22:43, Lu Baolu 写道: >>> Tweak the I/O page fault handling framework to route the page faults to >>> the domain and call the page fault handler retrieved from the domain. >>> This makes the I/O page fault handling framework possible to serve more >>> usage scenarios as long as they have an IOMMU domain and install a page >>> fault handler in it. Some unused functions are also removed to avoid >>> dead code. >>> >>> The iommu_get_domain_for_dev_pasid() which retrieves attached domain >>> for a {device, PASID} pair is used. It will be used by the page fault >>> handling framework which knows {device, PASID} reported from the iommu >>> driver. We have a guarantee that the SVA domain doesn't go away during >>> IOPF handling, because unbind() waits for pending faults with >>> iopf_queue_flush_dev() before freeing the domain. Hence, there's no >>> need >>> to synchronize life cycle of the iommu domains between the unbind() and >>> the interrupt threads. >>> >>> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> >>> Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org> >>> --- >>> drivers/iommu/io-pgfault.c | 64 >>> +++++--------------------------------- >>> 1 file changed, 7 insertions(+), 57 deletions(-) >>> >>> diff --git a/drivers/iommu/io-pgfault.c b/drivers/iommu/io-pgfault.c >>> index aee9e033012f..4f24ec703479 100644 >>> --- a/drivers/iommu/io-pgfault.c >>> +++ b/drivers/iommu/io-pgfault.c >>> @@ -69,69 +69,18 @@ static int iopf_complete_group(struct device >>> *dev, struct iopf_fault *iopf, >>> return iommu_page_response(dev, &resp); >>> } >>> -static enum iommu_page_response_code >>> -iopf_handle_single(struct iopf_fault *iopf) >>> -{ >>> - vm_fault_t ret; >>> - struct mm_struct *mm; >>> - struct vm_area_struct *vma; >>> - unsigned int access_flags = 0; >>> - unsigned int fault_flags = FAULT_FLAG_REMOTE; >>> - struct iommu_fault_page_request *prm = &iopf->fault.prm; >>> - enum iommu_page_response_code status = IOMMU_PAGE_RESP_INVALID; >>> - >>> - if (!(prm->flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID)) >>> - return status; >>> - >>> - mm = iommu_sva_find(prm->pasid); >>> - if (IS_ERR_OR_NULL(mm)) >>> - return status; >>> - >>> - mmap_read_lock(mm); >>> - >>> - vma = find_extend_vma(mm, prm->addr); >>> - if (!vma) >>> - /* Unmapped area */ >>> - goto out_put_mm; >>> - >>> - if (prm->perm & IOMMU_FAULT_PERM_READ) >>> - access_flags |= VM_READ; >>> - >>> - if (prm->perm & IOMMU_FAULT_PERM_WRITE) { >>> - access_flags |= VM_WRITE; >>> - fault_flags |= FAULT_FLAG_WRITE; >>> - } >>> - >>> - if (prm->perm & IOMMU_FAULT_PERM_EXEC) { >>> - access_flags |= VM_EXEC; >>> - fault_flags |= FAULT_FLAG_INSTRUCTION; >>> - } >>> - >>> - if (!(prm->perm & IOMMU_FAULT_PERM_PRIV)) >>> - fault_flags |= FAULT_FLAG_USER; >>> - >>> - if (access_flags & ~vma->vm_flags) >>> - /* Access fault */ >>> - goto out_put_mm; >>> - >>> - ret = handle_mm_fault(vma, prm->addr, fault_flags, NULL); >>> - status = ret & VM_FAULT_ERROR ? IOMMU_PAGE_RESP_INVALID : >>> - IOMMU_PAGE_RESP_SUCCESS; >>> - >>> -out_put_mm: >>> - mmap_read_unlock(mm); >>> - mmput(mm); >>> - >>> - return status; >>> -} >>> - >> >> Once the iopf_handle_single() is removed, the name of >> iopf_handle_group() looks a little weired >> >> and confused, does this group mean the iommu group (domain) ? while I >> take some minutes to > > No. This is not the iommu group. It's page request group defined by the > PCI SIG spec. Multiple page requests could be put in a group with a > same group id. All page requests in a group could be responded to device > in one shot.
Thanks your explaination, understand the concept of PCIe PRG. I meant
do we still have the necessity to mention the "group" here in the name
iopf_handle_group(), which one is better ? iopf_handle_prg() or
iopf_handler(), perhaps none of them ? :)
Thanks,
Ethan
> > Best regards, > baolu > >> >> look into the code, oh, means a batch / list / queue of iopfs , and >> iopf_handle_group() becomes a >> >> generic iopf_handler() . >> >> Doe it make sense to revise the names of iopf_handle_group(), >> iopf_complete_group, iopf_group in >> >> this patch set ? >> >> >> Thanks, >> >> Ethan >> >>> static void iopf_handle_group(struct work_struct *work) >>> { >>> struct iopf_group *group; >>> + struct iommu_domain *domain; >>> struct iopf_fault *iopf, *next; >>> enum iommu_page_response_code status = IOMMU_PAGE_RESP_SUCCESS; >>> group = container_of(work, struct iopf_group, work); >>> + domain = iommu_get_domain_for_dev_pasid(group->dev, >>> + group->last_fault.fault.prm.pasid); >>> + if (!domain || !domain->iopf_handler) >>> + status = IOMMU_PAGE_RESP_INVALID; >>> list_for_each_entry_safe(iopf, next, &group->faults, list) { >>> /* >>> @@ -139,7 +88,8 @@ static void iopf_handle_group(struct work_struct >>> *work) >>> * faults in the group if there is an error. >>> */ >>> if (status == IOMMU_PAGE_RESP_SUCCESS) >>> - status = iopf_handle_single(iopf); >>> + status = domain->iopf_handler(&iopf->fault, >>> + domain->fault_data); >>> if (!(iopf->fault.prm.flags & >>> IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE)) >> > -- "firm, enduring, strong, and long-lived"
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