1 /** @file 2 3 Declarations of utility functions used by virtio device drivers. 4 5 Copyright (C) 2012, Red Hat, Inc. 6 7 This program and the accompanying materials are licensed and made available 8 under the terms and conditions of the BSD License which accompanies this 9 distribution. The full text of the license may be found at 10 http://opensource.org/licenses/bsd-license.php 11 12 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT 13 WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 14 15 **/ 16 17 #ifndef _VIRTIO_LIB_H_ 18 #define _VIRTIO_LIB_H_ 19 20 #include <Protocol/VirtioDevice.h> 21 22 #include <IndustryStandard/Virtio.h> 23 24 25 /** 26 27 Configure a virtio ring. 28 29 This function sets up internal storage (the guest-host communication area) 30 and lays out several "navigation" (ie. no-ownership) pointers to parts of 31 that storage. 32 33 Relevant sections from the virtio-0.9.5 spec: 34 - 1.1 Virtqueues, 35 - 2.3 Virtqueue Configuration. 36 37 @param[in] The number of descriptors to allocate for the 38 virtio ring, as requested by the host. 39 40 @param[out] Ring The virtio ring to set up. 41 42 @retval EFI_OUT_OF_RESOURCES AllocatePages() failed to allocate contiguous 43 pages for the requested QueueSize. Fields of 44 Ring have indeterminate value. 45 46 @retval EFI_SUCCESS Allocation and setup successful. Ring->Base 47 (and nothing else) is responsible for 48 deallocation. 49 50 **/ 51 EFI_STATUS 52 EFIAPI 53 VirtioRingInit ( 54 IN UINT16 QueueSize, 55 OUT VRING *Ring 56 ); 57 58 59 /** 60 61 Tear down the internal resources of a configured virtio ring. 62 63 The caller is responsible to stop the host from using this ring before 64 invoking this function: the VSTAT_DRIVER_OK bit must be clear in 65 VhdrDeviceStatus. 66 67 @param[out] Ring The virtio ring to clean up. 68 69 **/ 70 VOID 71 EFIAPI 72 VirtioRingUninit ( 73 IN OUT VRING *Ring 74 ); 75 76 77 // 78 // Internal use structure for tracking the submission of a multi-descriptor 79 // request. 80 // 81 typedef struct { 82 UINT16 HeadDescIdx; 83 UINT16 NextDescIdx; 84 } DESC_INDICES; 85 86 87 /** 88 89 Turn off interrupt notifications from the host, and prepare for appending 90 multiple descriptors to the virtio ring. 91 92 The calling driver must be in VSTAT_DRIVER_OK state. 93 94 @param[in,out] Ring The virtio ring we intend to append descriptors to. 95 96 @param[out] Indices The DESC_INDICES structure to initialize. 97 98 **/ 99 VOID 100 EFIAPI 101 VirtioPrepare ( 102 IN OUT VRING *Ring, 103 OUT DESC_INDICES *Indices 104 ); 105 106 107 /** 108 109 Append a contiguous buffer for transmission / reception via the virtio ring. 110 111 This function implements the following section from virtio-0.9.5: 112 - 2.4.1.1 Placing Buffers into the Descriptor Table 113 114 Free space is taken as granted, since the individual drivers support only 115 synchronous requests and host side status is processed in lock-step with 116 request submission. It is the calling driver's responsibility to verify the 117 ring size in advance. 118 119 The caller is responsible for initializing *Indices with VirtioPrepare() 120 first. 121 122 @param[in,out] Ring The virtio ring to append the buffer to, as a 123 descriptor. 124 125 @param[in] BufferPhysAddr (Guest pseudo-physical) start address of the 126 transmit / receive buffer. 127 128 @param[in] BufferSize Number of bytes to transmit or receive. 129 130 @param[in] Flags A bitmask of VRING_DESC_F_* flags. The caller 131 computes this mask dependent on further buffers to 132 append and transfer direction. 133 VRING_DESC_F_INDIRECT is unsupported. The 134 VRING_DESC.Next field is always set, but the host 135 only interprets it dependent on VRING_DESC_F_NEXT. 136 137 @param[in,out] Indices Indices->HeadDescIdx is not accessed. 138 On input, Indices->NextDescIdx identifies the next 139 descriptor to carry the buffer. On output, 140 Indices->NextDescIdx is incremented by one, modulo 141 2^16. 142 143 **/ 144 VOID 145 EFIAPI 146 VirtioAppendDesc ( 147 IN OUT VRING *Ring, 148 IN UINTN BufferPhysAddr, 149 IN UINT32 BufferSize, 150 IN UINT16 Flags, 151 IN OUT DESC_INDICES *Indices 152 ); 153 154 155 /** 156 157 Notify the host about the descriptor chain just built, and wait until the 158 host processes it. 159 160 @param[in] VirtIo The target virtio device to notify. 161 162 @param[in] VirtQueueId Identifies the queue for the target device. 163 164 @param[in,out] Ring The virtio ring with descriptors to submit. 165 166 @param[in] Indices Indices->NextDescIdx is not accessed. 167 Indices->HeadDescIdx identifies the head descriptor 168 of the descriptor chain. 169 170 171 @return Error code from VirtIo->SetQueueNotify() if it fails. 172 173 @retval EFI_SUCCESS Otherwise, the host processed all descriptors. 174 175 **/ 176 EFI_STATUS 177 EFIAPI 178 VirtioFlush ( 179 IN VIRTIO_DEVICE_PROTOCOL *VirtIo, 180 IN UINT16 VirtQueueId, 181 IN OUT VRING *Ring, 182 IN DESC_INDICES *Indices 183 ); 184 185 #endif // _VIRTIO_LIB_H_ 186