>-----Original Message----- >From: Nath, Arindam >Sent: Monday, March 27, 2017 5:57 PM >To: 'Daniel Drake' >Cc: joro at 8bytes.org; Deucher, Alexander; Bridgman, John; amd- >gfx at lists.freedesktop.org; iommu at lists.linux-foundation.org; Suthikulpanit, >Suravee; Linux Upstreaming Team >Subject: RE: [PATCH] iommu/amd: flush IOTLB for specific domains only > >>-----Original Message----- >>From: Daniel Drake [mailto:drake at endlessm.com] >>Sent: Monday, March 27, 2017 5:56 PM >>To: Nath, Arindam >>Cc: joro at 8bytes.org; Deucher, Alexander; Bridgman, John; amd- >>gfx at lists.freedesktop.org; iommu at lists.linux-foundation.org; Suthikulpanit, >>Suravee; Linux Upstreaming Team >>Subject: Re: [PATCH] iommu/amd: flush IOTLB for specific domains only >> >>Hi Arindam, >> >>You CC'd me on this - does this mean that it is a fix for the issue >>described in the thread "amd-iommu: can't boot with amdgpu, AMD-Vi: >>Completion-Wait loop timed out" ? > >Yes Daniel, please test this patch to confirm if the issue gets resolved. Daniel, did you get chance to test this patch? Thanks, Arindam > >Thanks, >Arindam > >> >>Thanks >>Daniel >> >> >>On Mon, Mar 27, 2017 at 12:17 AM, <arindam.nath at amd.com> wrote: >>> From: Arindam Nath <arindam.nath at amd.com> >>> >>> The idea behind flush queues is to defer the IOTLB flushing >>> for domains for which the mappings are no longer valid. We >>> add such domains in queue_add(), and when the queue size >>> reaches FLUSH_QUEUE_SIZE, we perform __queue_flush(). >>> >>> Since we have already taken lock before __queue_flush() >>> is called, we need to make sure the IOTLB flushing is >>> performed as quickly as possible. >>> >>> In the current implementation, we perform IOTLB flushing >>> for all domains irrespective of which ones were actually >>> added in the flush queue initially. This can be quite >>> expensive especially for domains for which unmapping is >>> not required at this point of time. >>> >>> This patch makes use of domain information in >>> 'struct flush_queue_entry' to make sure we only flush >>> IOTLBs for domains who need it, skipping others. >>> >>> Signed-off-by: Arindam Nath <arindam.nath at amd.com> >>> --- >>> drivers/iommu/amd_iommu.c | 15 ++++++++------- >>> 1 file changed, 8 insertions(+), 7 deletions(-) >>> >>> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c >>> index 98940d1..6a9a048 100644 >>> --- a/drivers/iommu/amd_iommu.c >>> +++ b/drivers/iommu/amd_iommu.c >>> @@ -2227,15 +2227,16 @@ static struct iommu_group >>*amd_iommu_device_group(struct device *dev) >>> >>> static void __queue_flush(struct flush_queue *queue) >>> { >>> - struct protection_domain *domain; >>> - unsigned long flags; >>> int idx; >>> >>> - /* First flush TLB of all known domains */ >>> - spin_lock_irqsave(&amd_iommu_pd_lock, flags); >>> - list_for_each_entry(domain, &amd_iommu_pd_list, list) >>> - domain_flush_tlb(domain); >>> - spin_unlock_irqrestore(&amd_iommu_pd_lock, flags); >>> + /* First flush TLB of all domains which were added to flush queue */ >>> + for (idx = 0; idx < queue->next; ++idx) { >>> + struct flush_queue_entry *entry; >>> + >>> + entry = queue->entries + idx; >>> + >>> + domain_flush_tlb(&entry->dma_dom->domain); >>> + } >>> >>> /* Wait until flushes have completed */ >>> domain_flush_complete(NULL); >>> -- >>> 1.9.1 >>>
