diff options
Diffstat (limited to 'Documentation/vfio.txt')
| -rw-r--r-- | Documentation/vfio.txt | 87 |
1 files changed, 84 insertions, 3 deletions
diff --git a/Documentation/vfio.txt b/Documentation/vfio.txt index b9ca02370d46..96978eced341 100644 --- a/Documentation/vfio.txt +++ b/Documentation/vfio.txt @@ -305,7 +305,15 @@ faster, the map/unmap handling has been implemented in real mode which provides an excellent performance which has limitations such as inability to do locked pages accounting in real time. -So 3 additional ioctls have been added: +4) According to sPAPR specification, A Partitionable Endpoint (PE) is an I/O +subtree that can be treated as a unit for the purposes of partitioning and +error recovery. A PE may be a single or multi-function IOA (IO Adapter), a +function of a multi-function IOA, or multiple IOAs (possibly including switch +and bridge structures above the multiple IOAs). PPC64 guests detect PCI errors +and recover from them via EEH RTAS services, which works on the basis of +additional ioctl commands. + +So 4 additional ioctls have been added: VFIO_IOMMU_SPAPR_TCE_GET_INFO - returns the size and the start of the DMA window on the PCI bus. @@ -316,9 +324,12 @@ So 3 additional ioctls have been added: VFIO_IOMMU_DISABLE - disables the container. + VFIO_EEH_PE_OP - provides an API for EEH setup, error detection and recovery. The code flow from the example above should be slightly changed: + struct vfio_eeh_pe_op pe_op = { .argsz = sizeof(pe_op), .flags = 0 }; + ..... /* Add the group to the container */ ioctl(group, VFIO_GROUP_SET_CONTAINER, &container); @@ -342,9 +353,79 @@ The code flow from the example above should be slightly changed: dma_map.flags = VFIO_DMA_MAP_FLAG_READ | VFIO_DMA_MAP_FLAG_WRITE; /* Check here is .iova/.size are within DMA window from spapr_iommu_info */ - ioctl(container, VFIO_IOMMU_MAP_DMA, &dma_map); - ..... + + /* Get a file descriptor for the device */ + device = ioctl(group, VFIO_GROUP_GET_DEVICE_FD, "0000:06:0d.0"); + + .... + + /* Gratuitous device reset and go... */ + ioctl(device, VFIO_DEVICE_RESET); + + /* Make sure EEH is supported */ + ioctl(container, VFIO_CHECK_EXTENSION, VFIO_EEH); + + /* Enable the EEH functionality on the device */ + pe_op.op = VFIO_EEH_PE_ENABLE; + ioctl(container, VFIO_EEH_PE_OP, &pe_op); + + /* You're suggested to create additional data struct to represent + * PE, and put child devices belonging to same IOMMU group to the + * PE instance for later reference. + */ + + /* Check the PE's state and make sure it's in functional state */ + pe_op.op = VFIO_EEH_PE_GET_STATE; + ioctl(container, VFIO_EEH_PE_OP, &pe_op); + + /* Save device state using pci_save_state(). + * EEH should be enabled on the specified device. + */ + + .... + + /* When 0xFF's returned from reading PCI config space or IO BARs + * of the PCI device. Check the PE's state to see if that has been + * frozen. + */ + ioctl(container, VFIO_EEH_PE_OP, &pe_op); + + /* Waiting for pending PCI transactions to be completed and don't + * produce any more PCI traffic from/to the affected PE until + * recovery is finished. + */ + + /* Enable IO for the affected PE and collect logs. Usually, the + * standard part of PCI config space, AER registers are dumped + * as logs for further analysis. + */ + pe_op.op = VFIO_EEH_PE_UNFREEZE_IO; + ioctl(container, VFIO_EEH_PE_OP, &pe_op); + + /* + * Issue PE reset: hot or fundamental reset. Usually, hot reset + * is enough. However, the firmware of some PCI adapters would + * require fundamental reset. + */ + pe_op.op = VFIO_EEH_PE_RESET_HOT; + ioctl(container, VFIO_EEH_PE_OP, &pe_op); + pe_op.op = VFIO_EEH_PE_RESET_DEACTIVATE; + ioctl(container, VFIO_EEH_PE_OP, &pe_op); + + /* Configure the PCI bridges for the affected PE */ + pe_op.op = VFIO_EEH_PE_CONFIGURE; + ioctl(container, VFIO_EEH_PE_OP, &pe_op); + + /* Restored state we saved at initialization time. pci_restore_state() + * is good enough as an example. + */ + + /* Hopefully, error is recovered successfully. Now, you can resume to + * start PCI traffic to/from the affected PE. + */ + + .... ------------------------------------------------------------------------------- |