Re: [RFC 4/11] virtio-pci: define layout for virtio vendor-specific capabilities.
From: Sasha Levin <hidden>
Date: 2011-12-10 21:14:49
On Thu, 2011-12-08 at 21:04 +1030, Rusty Russell wrote:
quoted hunk ↗ jump to hunk
Based on patch by Michael S. Tsirkin [off-list ref], but I found it hard to follow so changed to use structures which are more self-documenting. Signed-off-by: Rusty Russell <redacted> --- include/linux/virtio_pci.h | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+)diff --git a/include/linux/virtio_pci.h b/include/linux/virtio_pci.h --- a/include/linux/virtio_pci.h +++ b/include/linux/virtio_pci.h@@ -92,4 +92,45 @@ /* The alignment to use between consumer and producer parts of vring. * x86 pagesize again. */ #define VIRTIO_PCI_VRING_ALIGN 4096 + +/* IDs for different capabilities. Must all exist. */ +/* FIXME: Do we win from separating ISR, NOTIFY and COMMON? */ +/* 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. */
There should be a cap_len field here, which is mandatory for PCI_CAP_ID_VNDR capabilities.
+ u8 cfg_type; /* One of the VIRTIO_PCI_CAP_*_CFG. */
+/* FIXME: Should we use a bir, instead of raw bar number? */
+ u8 bar; /* Where to find it. */
+ __le32 offset; /* Offset within bar. */
+ __le32 length; /* Length. */
+};
+
+/* 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-only */
+ __le16 msix_config; /* read-write */
+ __u8 device_status; /* read-write */
+ __u8 unused;
+
+ /* About a specific virtqueue. */
+ __le16 queue_select; /* read-write */
+ __le16 queue_align; /* read-write, power of 2. */
+ __le16 queue_size; /* read-write, power of 2. */
+ __le16 queue_msix_vector;/* read-write */
+ __le64 queue_address; /* read-write: 0xFFFFFFFFFFFFFFFF == DNE. */This is now a 64bit address, but we can't do an atomic iowrite64(). We should make it clear to the device when it should initialize the vq. -- Sasha.