73 lines
2.5 KiB
C
73 lines
2.5 KiB
C
//
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// virtio device definitions.
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// for both the mmio interface, and virtio descriptors.
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// only tested with qemu.
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// this is the "legacy" virtio interface.
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//
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// the virtio spec:
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// https://docs.oasis-open.org/virtio/virtio/v1.1/virtio-v1.1.pdf
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//
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// virtio mmio control registers, mapped starting at 0x10001000.
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// from qemu virtio_mmio.h
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#define VIRTIO_MMIO_MAGIC_VALUE 0x000 // 0x74726976
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#define VIRTIO_MMIO_VERSION 0x004 // version; 1 is legacy
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#define VIRTIO_MMIO_DEVICE_ID 0x008 // device type; 1 is net, 2 is disk
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#define VIRTIO_MMIO_VENDOR_ID 0x00c // 0x554d4551
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#define VIRTIO_MMIO_DEVICE_FEATURES 0x010
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#define VIRTIO_MMIO_DRIVER_FEATURES 0x020
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#define VIRTIO_MMIO_GUEST_PAGE_SIZE 0x028 // page size for PFN, write-only
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#define VIRTIO_MMIO_QUEUE_SEL 0x030 // select queue, write-only
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#define VIRTIO_MMIO_QUEUE_NUM_MAX 0x034 // max size of current queue, read-only
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#define VIRTIO_MMIO_QUEUE_NUM 0x038 // size of current queue, write-only
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#define VIRTIO_MMIO_QUEUE_ALIGN 0x03c // used ring alignment, write-only
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#define VIRTIO_MMIO_QUEUE_PFN 0x040 // physical page number for queue, read/write
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#define VIRTIO_MMIO_QUEUE_READY 0x044 // ready bit
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#define VIRTIO_MMIO_QUEUE_NOTIFY 0x050 // write-only
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#define VIRTIO_MMIO_INTERRUPT_STATUS 0x060 // read-only
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#define VIRTIO_MMIO_INTERRUPT_ACK 0x064 // write-only
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#define VIRTIO_MMIO_STATUS 0x070 // read/write
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// status register bits, from qemu virtio_config.h
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#define VIRTIO_CONFIG_S_ACKNOWLEDGE 1
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#define VIRTIO_CONFIG_S_DRIVER 2
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#define VIRTIO_CONFIG_S_DRIVER_OK 4
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#define VIRTIO_CONFIG_S_FEATURES_OK 8
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// device feature bits
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#define VIRTIO_BLK_F_RO 5 /* Disk is read-only */
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#define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */
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#define VIRTIO_BLK_F_CONFIG_WCE 11 /* Writeback mode available in config */
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#define VIRTIO_BLK_F_MQ 12 /* support more than one vq */
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#define VIRTIO_F_ANY_LAYOUT 27
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#define VIRTIO_RING_F_INDIRECT_DESC 28
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#define VIRTIO_RING_F_EVENT_IDX 29
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// this many virtio descriptors.
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// must be a power of two.
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#define NUM 8
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struct VRingDesc {
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uint64 addr;
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uint32 len;
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uint16 flags;
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uint16 next;
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};
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#define VRING_DESC_F_NEXT 1 // chained with another descriptor
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#define VRING_DESC_F_WRITE 2 // device writes (vs read)
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struct VRingUsedElem {
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uint32 id; // index of start of completed descriptor chain
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uint32 len;
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};
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// for disk ops
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#define VIRTIO_BLK_T_IN 0 // read the disk
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#define VIRTIO_BLK_T_OUT 1 // write the disk
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struct UsedArea {
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uint16 flags;
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uint16 id;
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struct VRingUsedElem elems[NUM];
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};
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