diff options
Diffstat (limited to 'OvmfPkg/VirtioFsDxe/Helpers.c')
| -rw-r--r-- | OvmfPkg/VirtioFsDxe/Helpers.c | 299 |
1 files changed, 299 insertions, 0 deletions
diff --git a/OvmfPkg/VirtioFsDxe/Helpers.c b/OvmfPkg/VirtioFsDxe/Helpers.c new file mode 100644 index 0000000000..7b4906c541 --- /dev/null +++ b/OvmfPkg/VirtioFsDxe/Helpers.c @@ -0,0 +1,299 @@ +/** @file
+ Initialization and helper routines for the Virtio Filesystem device.
+
+ Copyright (C) 2020, Red Hat, Inc.
+
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#include <Library/VirtioLib.h> // Virtio10WriteFeatures()
+
+#include "VirtioFsDxe.h"
+
+/**
+ Read the Virtio Filesystem device configuration structure in full.
+
+ @param[in] Virtio The Virtio protocol underlying the VIRTIO_FS object.
+
+ @param[out] Config The fully populated VIRTIO_FS_CONFIG structure.
+
+ @retval EFI_SUCCESS Config has been filled in.
+
+ @return Error codes propagated from Virtio->ReadDevice(). The
+ contents of Config are indeterminate.
+**/
+STATIC
+EFI_STATUS
+VirtioFsReadConfig (
+ IN VIRTIO_DEVICE_PROTOCOL *Virtio,
+ OUT VIRTIO_FS_CONFIG *Config
+ )
+{
+ UINTN Idx;
+ EFI_STATUS Status;
+
+ for (Idx = 0; Idx < VIRTIO_FS_TAG_BYTES; Idx++) {
+ Status = Virtio->ReadDevice (
+ Virtio, // This
+ OFFSET_OF (VIRTIO_FS_CONFIG, Tag[Idx]), // FieldOffset
+ sizeof Config->Tag[Idx], // FieldSize
+ sizeof Config->Tag[Idx], // BufferSize
+ &Config->Tag[Idx] // Buffer
+ );
+ if (EFI_ERROR (Status)) {
+ return Status;
+ }
+ }
+
+ Status = Virtio->ReadDevice (
+ Virtio, // This
+ OFFSET_OF (VIRTIO_FS_CONFIG, NumReqQueues), // FieldOffset
+ sizeof Config->NumReqQueues, // FieldSize
+ sizeof Config->NumReqQueues, // BufferSize
+ &Config->NumReqQueues // Buffer
+ );
+ return Status;
+}
+
+/**
+ Configure the Virtio Filesystem device underlying VirtioFs.
+
+ @param[in,out] VirtioFs The VIRTIO_FS object for which Virtio communication
+ should be set up. On input, the caller is
+ responsible for VirtioFs->Virtio having been
+ initialized. On output, synchronous Virtio
+ Filesystem commands (primitives) may be submitted to
+ the device.
+
+ @retval EFI_SUCCESS Virtio machinery has been set up.
+
+ @retval EFI_UNSUPPORTED The host-side configuration of the Virtio Filesystem
+ is not supported by this driver.
+
+ @return Error codes from underlying functions.
+**/
+EFI_STATUS
+VirtioFsInit (
+ IN OUT VIRTIO_FS *VirtioFs
+ )
+{
+ UINT8 NextDevStat;
+ EFI_STATUS Status;
+ UINT64 Features;
+ VIRTIO_FS_CONFIG Config;
+ UINTN Idx;
+ UINT64 RingBaseShift;
+
+ //
+ // Execute virtio-v1.1-cs01-87fa6b5d8155, 3.1.1 Driver Requirements: Device
+ // Initialization.
+ //
+ // 1. Reset the device.
+ //
+ NextDevStat = 0;
+ Status = VirtioFs->Virtio->SetDeviceStatus (VirtioFs->Virtio, NextDevStat);
+ if (EFI_ERROR (Status)) {
+ goto Failed;
+ }
+
+ //
+ // 2. Set the ACKNOWLEDGE status bit [...]
+ //
+ NextDevStat |= VSTAT_ACK;
+ Status = VirtioFs->Virtio->SetDeviceStatus (VirtioFs->Virtio, NextDevStat);
+ if (EFI_ERROR (Status)) {
+ goto Failed;
+ }
+
+ //
+ // 3. Set the DRIVER status bit [...]
+ //
+ NextDevStat |= VSTAT_DRIVER;
+ Status = VirtioFs->Virtio->SetDeviceStatus (VirtioFs->Virtio, NextDevStat);
+ if (EFI_ERROR (Status)) {
+ goto Failed;
+ }
+
+ //
+ // 4. Read device feature bits...
+ //
+ Status = VirtioFs->Virtio->GetDeviceFeatures (VirtioFs->Virtio, &Features);
+ if (EFI_ERROR (Status)) {
+ goto Failed;
+ }
+ if ((Features & VIRTIO_F_VERSION_1) == 0) {
+ Status = EFI_UNSUPPORTED;
+ goto Failed;
+ }
+ //
+ // No device-specific feature bits have been defined in file "virtio-fs.tex"
+ // of the virtio spec at <https://github.com/oasis-tcs/virtio-spec.git>, as
+ // of commit 87fa6b5d8155.
+ //
+ Features &= VIRTIO_F_VERSION_1 | VIRTIO_F_IOMMU_PLATFORM;
+
+ //
+ // ... and write the subset of feature bits understood by the [...] driver to
+ // the device. [...]
+ // 5. Set the FEATURES_OK status bit.
+ // 6. Re-read device status to ensure the FEATURES_OK bit is still set [...]
+ //
+ Status = Virtio10WriteFeatures (VirtioFs->Virtio, Features, &NextDevStat);
+ if (EFI_ERROR (Status)) {
+ goto Failed;
+ }
+
+ //
+ // 7. Perform device-specific setup, including discovery of virtqueues for
+ // the device, [...] reading [...] the device's virtio configuration space
+ //
+ Status = VirtioFsReadConfig (VirtioFs->Virtio, &Config);
+ if (EFI_ERROR (Status)) {
+ goto Failed;
+ }
+
+ //
+ // 7.a. Convert the filesystem label from UTF-8 to UCS-2. Only labels with
+ // printable ASCII code points (U+0020 through U+007E) are supported.
+ // NUL-terminate at either the terminator we find, or right after the
+ // original label.
+ //
+ for (Idx = 0; Idx < VIRTIO_FS_TAG_BYTES && Config.Tag[Idx] != '\0'; Idx++) {
+ if (Config.Tag[Idx] < 0x20 || Config.Tag[Idx] > 0x7E) {
+ Status = EFI_UNSUPPORTED;
+ goto Failed;
+ }
+ VirtioFs->Label[Idx] = Config.Tag[Idx];
+ }
+ VirtioFs->Label[Idx] = L'\0';
+
+ //
+ // 7.b. We need one queue for sending normal priority requests.
+ //
+ if (Config.NumReqQueues < 1) {
+ Status = EFI_UNSUPPORTED;
+ goto Failed;
+ }
+
+ //
+ // 7.c. Fetch and remember the number of descriptors we can place on the
+ // queue at once. We'll need two descriptors per request, as a minimum --
+ // request header, response header.
+ //
+ Status = VirtioFs->Virtio->SetQueueSel (VirtioFs->Virtio,
+ VIRTIO_FS_REQUEST_QUEUE);
+ if (EFI_ERROR (Status)) {
+ goto Failed;
+ }
+ Status = VirtioFs->Virtio->GetQueueNumMax (VirtioFs->Virtio,
+ &VirtioFs->QueueSize);
+ if (EFI_ERROR (Status)) {
+ goto Failed;
+ }
+ if (VirtioFs->QueueSize < 2) {
+ Status = EFI_UNSUPPORTED;
+ goto Failed;
+ }
+
+ //
+ // 7.d. [...] population of virtqueues [...]
+ //
+ Status = VirtioRingInit (VirtioFs->Virtio, VirtioFs->QueueSize,
+ &VirtioFs->Ring);
+ if (EFI_ERROR (Status)) {
+ goto Failed;
+ }
+
+ Status = VirtioRingMap (VirtioFs->Virtio, &VirtioFs->Ring, &RingBaseShift,
+ &VirtioFs->RingMap);
+ if (EFI_ERROR (Status)) {
+ goto ReleaseQueue;
+ }
+
+ Status = VirtioFs->Virtio->SetQueueAddress (VirtioFs->Virtio,
+ &VirtioFs->Ring, RingBaseShift);
+ if (EFI_ERROR (Status)) {
+ goto UnmapQueue;
+ }
+
+ //
+ // 8. Set the DRIVER_OK status bit.
+ //
+ NextDevStat |= VSTAT_DRIVER_OK;
+ Status = VirtioFs->Virtio->SetDeviceStatus (VirtioFs->Virtio, NextDevStat);
+ if (EFI_ERROR (Status)) {
+ goto UnmapQueue;
+ }
+
+ return EFI_SUCCESS;
+
+UnmapQueue:
+ VirtioFs->Virtio->UnmapSharedBuffer (VirtioFs->Virtio, VirtioFs->RingMap);
+
+ReleaseQueue:
+ VirtioRingUninit (VirtioFs->Virtio, &VirtioFs->Ring);
+
+Failed:
+ //
+ // If any of these steps go irrecoverably wrong, the driver SHOULD set the
+ // FAILED status bit to indicate that it has given up on the device (it can
+ // reset the device later to restart if desired). [...]
+ //
+ // Virtio access failure here should not mask the original error.
+ //
+ NextDevStat |= VSTAT_FAILED;
+ VirtioFs->Virtio->SetDeviceStatus (VirtioFs->Virtio, NextDevStat);
+
+ return Status;
+}
+
+/**
+ De-configure the Virtio Filesystem device underlying VirtioFs.
+
+ @param[in] VirtioFs The VIRTIO_FS object for which Virtio communication
+ should be torn down. On input, the caller is responsible
+ for having called VirtioFsInit(). On output, Virtio
+ Filesystem commands (primitives) must no longer be
+ submitted to the device.
+**/
+VOID
+VirtioFsUninit (
+ IN OUT VIRTIO_FS *VirtioFs
+ )
+{
+ //
+ // Resetting the Virtio device makes it release its resources and forget its
+ // configuration.
+ //
+ VirtioFs->Virtio->SetDeviceStatus (VirtioFs->Virtio, 0);
+ VirtioFs->Virtio->UnmapSharedBuffer (VirtioFs->Virtio, VirtioFs->RingMap);
+ VirtioRingUninit (VirtioFs->Virtio, &VirtioFs->Ring);
+}
+
+/**
+ ExitBootServices event notification function for a Virtio Filesystem object.
+
+ This function resets the VIRTIO_FS.Virtio device, causing it to release all
+ references to guest-side resources. The function may only be called after
+ VirtioFsInit() returns successfully and before VirtioFsUninit() is called.
+
+ @param[in] ExitBootEvent The VIRTIO_FS.ExitBoot event that has been
+ signaled.
+
+ @param[in] VirtioFsAsVoid Pointer to the VIRTIO_FS object, passed in as
+ (VOID*).
+**/
+VOID
+EFIAPI
+VirtioFsExitBoot (
+ IN EFI_EVENT ExitBootEvent,
+ IN VOID *VirtioFsAsVoid
+ )
+{
+ VIRTIO_FS *VirtioFs;
+
+ VirtioFs = VirtioFsAsVoid;
+ DEBUG ((DEBUG_VERBOSE, "%a: VirtioFs=0x%p Label=\"%s\"\n", __FUNCTION__,
+ VirtioFsAsVoid, VirtioFs->Label));
+ VirtioFs->Virtio->SetDeviceStatus (VirtioFs->Virtio, 0);
+}
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