On Tue, 10 Oct 2017 15:40:54 +0200 Joerg Roedel <j...@8bytes.org> wrote:
> On Thu, Oct 05, 2017 at 04:03:38PM -0700, Jacob Pan wrote: > > Traditionally, device specific faults are detected and handled > > within their own device drivers. When IOMMU is enabled, faults such > > as DMA related transactions are detected by IOMMU. There is no > > generic reporting mechanism to report faults back to the in-kernel > > device driver or the guest OS in case of assigned devices. > > > > Faults detected by IOMMU is based on the transaction's source ID > > which can be reported at per device basis, regardless of the device > > type is a PCI device or not. > > > > The fault types include recoverable (e.g. page request) and > > unrecoverable faults(e.g. access error). In most cases, faults can > > be handled by IOMMU drivers internally. The primary use cases are as > > follows: > > 1. page request fault originated from an SVM capable device that is > > assigned to guest via vIOMMU. In this case, the first level page > > tables are owned by the guest. Page request must be propagated to > > the guest to let guest OS fault in the pages then send page > > response. In this mechanism, the direct receiver of IOMMU fault > > notification is VFIO, which can relay notification events to QEMU > > or other user space software. > > > > 2. faults need more subtle handling by device drivers. Other than > > simply invoke reset function, there are needs to let device driver > > handle the fault with a smaller impact. > > > > This patchset is intended to create a generic fault report API such > > that it can scale as follows: > > - all IOMMU types > > - PCI and non-PCI devices > > - recoverable and unrecoverable faults > > - VFIO and other other in kernel users > > - DMA & IRQ remapping (TBD) > > The original idea was brought up by David Woodhouse and discussions > > summarized at https://lwn.net/Articles/608914/. > > > > Signed-off-by: Jacob Pan <jacob.jun....@linux.intel.com> > > Signed-off-by: Ashok Raj <ashok....@intel.com> > > --- > > drivers/iommu/iommu.c | 56 > > ++++++++++++++++++++++++++++++++++++++++++++++++++- > > include/linux/iommu.h | 23 +++++++++++++++++++++ 2 files changed, > > 78 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > > index 5a14154..0b058e2 100644 > > --- a/drivers/iommu/iommu.c > > +++ b/drivers/iommu/iommu.c > > @@ -554,9 +554,15 @@ int iommu_group_add_device(struct iommu_group > > *group, struct device *dev) > > device->dev = dev; > > > > + dev->iommu_fault_param = kzalloc(sizeof(struct > > iommu_fault_param), GFP_KERNEL); > > + if (!dev->iommu_fault_param) { > > + ret = -ENOMEM; > > + goto err_free_device; > > + } > > + > > This looks like some left-over from a previous version, because > allocation of that structure is done in > iommu_register_device_fault_handler() > you are right! I later changed it to do allocation at the handler registration time. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
