:github_url: https://github.com/nyx-org/gaia


.. _program_listing_file_dev_virtio_virtio.hpp:

Program Listing for File virtio.hpp
===================================

|exhale_lsh| :ref:`Return to documentation for file <file_dev_virtio_virtio.hpp>` (``dev/virtio/virtio.hpp``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   /* SPDX-License-Identifier: BSD-2-Clause */
   #pragma once
   #include <dev/devkit/service.hpp>
   #include <dev/pci/device.hpp>
   #include <hal/int.hpp>
   #include <vm/heap.hpp>
   
   #ifdef __amd64__
   #include <amd64/idt.hpp>
   #endif
   
   namespace Gaia::Dev {
   
   struct VirtQueueDesc {
     /* Address (guest-physical). */
     uint64_t addr;
     /* Length. */
     uint32_t len;
     /* The flags as indicated above. */
     uint16_t flags;
     /* We chain unused descriptors via this, too */
     uint16_t next;
   };
   
   struct VirtQueueAvail {
     uint16_t flags;
     uint16_t idx;
     uint16_t ring[];
   };
   
   struct VirtQueueUsedElem {
     /* Index of start of used descriptor chain. */
     uint32_t id;
   
     /* Total length of the descriptor chain which was written to. */
     uint32_t len;
   };
   
   struct VirtQueueUsed {
     uint32_t flags;
     uint32_t idx;
     VirtQueueUsedElem ring[];
     /* Only if VIRTIO_F_EVENT_IDX: le16 avail_event; */
   };
   
   struct VirtQueue {
     uint16_t num;
     uint16_t num_free, num_max;
     uint16_t notify_off;
   
     uint16_t last_free_desc;
   
     VirtQueueDesc *desc;
     VirtQueueAvail *avail;
     VirtQueueUsed *used;
   
     uint16_t allocate_desc();
     void free_desc(uint16_t desc);
   };
   
   class VirtioDevice : public Service {
   public:
     VirtioDevice();
     static Vm::UniquePtr<Service> create();
     static void int_handler(Hal::InterruptFrame *frame, void *arg);
   
     void start(Service *provider) override;
   
     bool match_properties(Properties &props) override;
   
     const char *class_name() override { return "VirtioDevice"; }
     const char *name() override { return name_str.data(); }
   
     void enable();
   
     void setup_queue(VirtQueue &queue, uint16_t index);
   
     void notify_queue(VirtQueue &queue);
   
     void *device_cfg;
   
   protected:
     PciDevice *device;
     frg::string<Gaia::Vm::HeapAllocator> name_str = "";
     uint16_t device_id;
     Hal::InterruptEntry int_entry;
   
     struct [[gnu::packed]] PciCommonCfg {
       /* About the whole device. */
       uint32_t device_feature_select; /* read-write */
       uint32_t device_feature;        /* read-only for driver */
       uint32_t driver_feature_select; /* read-write */
       uint32_t driver_feature;        /* read-write */
       uint16_t msix_config;           /* read-write */
       uint16_t num_queues;            /* read-only for driver */
       uint8_t device_status;          /* read-write */
       uint8_t config_generation;      /* read-only for driver */
   
       /* About a specific virtqueue. */
       uint16_t queue_select;      /* read-write */
       uint16_t queue_size;        /* read-write */
       uint16_t queue_msix_vector; /* read-write */
       uint16_t queue_enable;      /* read-write */
       uint16_t queue_notify_off;  /* read-only for driver */
       uint64_t queue_desc;        /* read-write */
       uint64_t queue_avail;       /* read-write */
       uint64_t queue_used;        /* read-write */
     };
   
     struct [[gnu::packed]] PciCap {
       uint8_t cap_vndr;   /* Generic PCI field: PCI_CAP_ID_VNDR */
       uint8_t cap_next;   /* Generic PCI field: next ptr. */
       uint8_t cap_len;    /* Generic PCI field: capability length */
       uint8_t cfg_type;   /* Identifies the structure. */
       uint8_t bar;        /* Where to find it. */
       uint8_t padding[3]; /* Pad to full dword. */
       uint32_t offset;    /* Offset within bar. */
       uint32_t length;    /* Length of the structure, in bytes. */
     };
   
     enum class PciCapType {
       COMMON_CFG = 1,
       NOTIFY_CFG = 2,
       ISR_CFG = 3,
       DEVICE_CFG = 4,
       PCI_CFG = 5,
     };
   
     void handle_capability(PciCap cap, uint32_t cap_off);
   
     PciCommonCfg *common_cfg;
     uintptr_t notify_base, notify_off_multiplier;
   
     Vm::UniquePtr<Service> driver;
   };
   
   void virtiodevice_driver_register();
   
   } // namespace Gaia::Dev