On 9/17/19 1:23 PM, David Rientjes wrote: > On Mon, 16 Sep 2019, David Rientjes wrote: > >> Brijesh and Tom, we currently hit this any time we boot an SEV enabled >> Ubuntu 18.04 guest; I assume that guest kernels, especially those of such >> major distributions, are expected to work with warnings and BUGs when >> certain drivers are enabled. >> >> If the vmap purge lock is to remain a mutex (any other reason that >> unmapping aliases can block?) then it appears that allocating a dmapool >> is the only alternative. Is this something that you'll be addressing >> generically or do we need to get buy-in from the maintainers of this >> specific driver? >> > > We've found that the following applied on top of 5.2.14 suppresses the > warnings. > > Christoph, Keith, Jens, is this something that we could do for the nvme > driver? I'll happily propose it formally if it would be acceptable. > > Thanks! > > > diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c > --- a/drivers/nvme/host/pci.c > +++ b/drivers/nvme/host/pci.c > @@ -1613,7 +1613,8 @@ static int nvme_alloc_admin_tags(struct nvme_dev *dev) > dev->admin_tagset.timeout = ADMIN_TIMEOUT; > dev->admin_tagset.numa_node = dev_to_node(dev->dev); > dev->admin_tagset.cmd_size = sizeof(struct nvme_iod); > - dev->admin_tagset.flags = BLK_MQ_F_NO_SCHED; > + dev->admin_tagset.flags = BLK_MQ_F_NO_SCHED | > + BLK_MQ_F_BLOCKING;
I think you want to only set the BLK_MQ_F_BLOCKING if the DMA is required to be unencrypted. Unfortunately, force_dma_unencrypted() can't be called from a module. Is there a DMA API that could be called to get that info? Thanks, Tom > dev->admin_tagset.driver_data = dev; > > if (blk_mq_alloc_tag_set(&dev->admin_tagset)) > @@ -2262,7 +2263,8 @@ static int nvme_dev_add(struct nvme_dev *dev) > dev->tagset.queue_depth = > min_t(int, dev->q_depth, BLK_MQ_MAX_DEPTH) - 1; > dev->tagset.cmd_size = sizeof(struct nvme_iod); > - dev->tagset.flags = BLK_MQ_F_SHOULD_MERGE; > + dev->tagset.flags = BLK_MQ_F_SHOULD_MERGE | > + BLK_MQ_F_BLOCKING; > dev->tagset.driver_data = dev; > > ret = blk_mq_alloc_tag_set(&dev->tagset); > _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
