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This makes lguest able to use the virtio devices. We change the device descriptor page from a simple array to a variable length "type, config_len, status, config data..." format, and implement virtio_config_ops to read from that config data. We use the virtio ring implementation for an efficient Guest <-> Host virtqueue mechanism, and the new LHCALL_NOTIFY hypercall to kick the host when it changes. We also use LHCALL_NOTIFY on kernel addresses for very very early console output. We could have another hypercall, but this hack works quite well. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
59 lines
2 KiB
C
59 lines
2 KiB
C
#ifndef _ASM_LGUEST_USER
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#define _ASM_LGUEST_USER
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/* Everything the "lguest" userspace program needs to know. */
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#include <linux/types.h>
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/* They can register up to 32 arrays of lguest_dma. */
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#define LGUEST_MAX_DMA 32
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/* At most we can dma 16 lguest_dma in one op. */
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#define LGUEST_MAX_DMA_SECTIONS 16
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/* How many devices? Assume each one wants up to two dma arrays per device. */
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#define LGUEST_MAX_DEVICES (LGUEST_MAX_DMA/2)
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/* Where the Host expects the Guest to SEND_DMA console output to. */
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#define LGUEST_CONSOLE_DMA_KEY 0
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/*D:010
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* Drivers
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*
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* The Guest needs devices to do anything useful. Since we don't let it touch
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* real devices (think of the damage it could do!) we provide virtual devices.
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* We could emulate a PCI bus with various devices on it, but that is a fairly
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* complex burden for the Host and suboptimal for the Guest, so we have our own
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* "lguest" bus and simple drivers.
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*
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* Devices are described by a simplified ID, a status byte, and some "config"
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* bytes which describe this device's configuration. This is placed by the
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* Launcher just above the top of physical memory:
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*/
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struct lguest_device_desc {
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/* The device type: console, network, disk etc. Type 0 terminates. */
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__u8 type;
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/* The number of bytes of the config array. */
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__u8 config_len;
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/* A status byte, written by the Guest. */
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__u8 status;
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__u8 config[0];
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};
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/*D:135 This is how we expect the device configuration field for a virtqueue
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* (type VIRTIO_CONFIG_F_VIRTQUEUE) to be laid out: */
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struct lguest_vqconfig {
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/* The number of entries in the virtio_ring */
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__u16 num;
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/* The interrupt we get when something happens. */
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__u16 irq;
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/* The page number of the virtio ring for this device. */
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__u32 pfn;
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};
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/*:*/
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/* Write command first word is a request. */
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enum lguest_req
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{
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LHREQ_INITIALIZE, /* + pfnlimit, pgdir, start, pageoffset */
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LHREQ_GETDMA, /* No longer used */
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LHREQ_IRQ, /* + irq */
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LHREQ_BREAK, /* + on/off flag (on blocks until someone does off) */
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};
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#endif /* _ASM_LGUEST_USER */
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