diff options
Diffstat (limited to 'virtio-v1.0-wd01-part1-specification.txt')
| -rw-r--r-- | virtio-v1.0-wd01-part1-specification.txt | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/virtio-v1.0-wd01-part1-specification.txt b/virtio-v1.0-wd01-part1-specification.txt index cfbb60f..f5f552a 100644 --- a/virtio-v1.0-wd01-part1-specification.txt +++ b/virtio-v1.0-wd01-part1-specification.txt @@ -1124,6 +1124,8 @@ cfg_type #define VIRTIO_PCI_CAP_ISR_CFG 3 /* Device specific configuration */ #define VIRTIO_PCI_CAP_DEVICE_CFG 4 + /* PCI configuration access */ + #define VIRTIO_PCI_CAP_PCI_CFG 5 Any other value - reserved for future use. Drivers must ignore any vendor-specific capability structure which has @@ -1187,6 +1189,30 @@ notify_off_multiplier If notify_off_multiplier is 0, all virtqueues use the same address in the Notifications structure! +If cfg_type is VIRTIO_PCI_CAP_PCI_CFG the fields bar, offset and length are RW +and this structure is immediately followed by an additional field: + +struct virtio_pci_cfg_cap { + __u8 pci_cfg_data[4]; /* Data for BAR access. */ +}; + +pci_cfg_data + + This RW field allows an indirect access to any BAR on the + device using PCI configuration accesses. + + The BAR to access is selected using the bar field. + The length of the access is specified by the length + field, which can be set to 1, 2 and 4. + The offset within the BAR is specified by the offset + field, which must be aligned to length bytes. + + After this field is written by driver, the first length + bytes in pci_cfg_data are written at the selected + offset in the selected BAR. + + When this field is read by driver, length bytes at the + selected offset in the selected BAR are read into pci_cfg_data. 100.100.1.3.1.1. Legacy Interface: A Note on Device Layout Detection ------------------------------- |