virtio-pci: define layout for virtio 1.0

Based on patches by Michael S. Tsirkin <mst@redhat.com>, but I found it
hard to follow so changed to use structures which are more
self-documenting.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 62 insertions, 0 deletions

diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
index 509d630f04f4..4e054235358f 100644
--- a/include/uapi/linux/virtio_pci.h
+++ b/include/uapi/linux/virtio_pci.h
@@ -99,4 +99,66 @@
 /* Vector value used to disable MSI for queue */
 #define VIRTIO_MSI_NO_VECTOR            0xffff
 
+#ifndef VIRTIO_PCI_NO_MODERN
+
+/* IDs for different capabilities.  Must all exist. */
+
+/* Common configuration */
+#define VIRTIO_PCI_CAP_COMMON_CFG       1
+/* Notifications */
+#define VIRTIO_PCI_CAP_NOTIFY_CFG       2
+/* ISR access */
+#define VIRTIO_PCI_CAP_ISR_CFG          3
+/* Device specific confiuration */
+#define VIRTIO_PCI_CAP_DEVICE_CFG       4
+
+/* This is the PCI capability header: */
+struct virtio_pci_cap {
+        __u8 cap_vndr;          /* Generic PCI field: PCI_CAP_ID_VNDR */
+        __u8 cap_next;          /* Generic PCI field: next ptr. */
+        __u8 cap_len;           /* Generic PCI field: capability length */
+        __u8 type_and_bar;      /* Upper 3 bits: bar.
+                                 * Lower 3 is VIRTIO_PCI_CAP_*_CFG. */
+        __le32 offset;          /* Offset within bar. */
+        __le32 length;          /* Length. */
+};
+
+#define VIRTIO_PCI_CAP_BAR_SHIFT        5
+#define VIRTIO_PCI_CAP_BAR_MASK         0x7
+#define VIRTIO_PCI_CAP_TYPE_SHIFT       0
+#define VIRTIO_PCI_CAP_TYPE_MASK        0x7
+
+struct virtio_pci_notify_cap {
+        struct virtio_pci_cap cap;
+        __le32 notify_off_multiplier;   /* Multiplier for queue_notify_off. */
+};
+
+/* Fields in VIRTIO_PCI_CAP_COMMON_CFG: */
+struct virtio_pci_common_cfg {
+        /* About the whole device. */
+        __le32 device_feature_select;   /* read-write */
+        __le32 device_feature;          /* read-only */
+        __le32 guest_feature_select;    /* read-write */
+        __le32 guest_feature;           /* read-write */
+        __le16 msix_config;             /* read-write */
+        __le16 num_queues;              /* read-only */
+        __u8 device_status;             /* read-write */
+        __u8 config_generation;         /* read-only */
+
+        /* About a specific virtqueue. */
+        __le16 queue_select;            /* read-write */
+        __le16 queue_size;              /* read-write, power of 2. */
+        __le16 queue_msix_vector;       /* read-write */
+        __le16 queue_enable;            /* read-write */
+        __le16 queue_notify_off;        /* read-only */
+        __le32 queue_desc_lo;           /* read-write */
+        __le32 queue_desc_hi;           /* read-write */
+        __le32 queue_avail_lo;          /* read-write */
+        __le32 queue_avail_hi;          /* read-write */
+        __le32 queue_used_lo;           /* read-write */
+        __le32 queue_used_hi;           /* read-write */
+};
+
+#endif /* VIRTIO_PCI_NO_MODERN */
+
 #endif