2018-03-26 06:10:07 +00:00
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# Virtio driver {#virtio}
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2017-10-02 17:31:06 +00:00
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# Introduction {#virtio_intro}
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2018-03-26 06:10:07 +00:00
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SPDK Virtio driver is a C library that allows communicating with Virtio devices.
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It allows any SPDK application to become an initiator for (SPDK) vhost targets.
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2017-10-02 17:31:06 +00:00
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2018-03-26 06:10:07 +00:00
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The driver supports two different usage models:
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2017-10-02 17:31:06 +00:00
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* PCI - This is the standard mode of operation when used in a guest virtual
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machine, where QEMU has presented the virtio controller as a virtual PCI device.
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* vhost-user - Can be used to connect to a vhost socket directly on the same host.
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2017-10-02 17:31:06 +00:00
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2018-01-30 12:53:45 +00:00
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The driver, just like the SPDK @ref vhost, is using pollers instead of standard
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interrupts to check for an I/O response. If used inside a VM, it bypasses interrupt
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and context switching overhead of QEMU and guest kernel, significantly boosting
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the overall I/O performance.
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2017-10-02 17:31:06 +00:00
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2018-03-26 06:10:07 +00:00
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This Virtio library is currently used to implement two bdev modules:
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@ref bdev_config_virtio_scsi and Virtio Blk. These modules will export generic
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2018-04-24 09:51:28 +00:00
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SPDK block devices usable by any SPDK application.
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