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Diffstat (limited to 'components/drivers/virtio/README.md')
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1 files changed, 7 insertions, 74 deletions
diff --git a/components/drivers/virtio/README.md b/components/drivers/virtio/README.md index 10278a24ed..f605b7b3a2 100644 --- a/components/drivers/virtio/README.md +++ b/components/drivers/virtio/README.md @@ -1,5 +1,7 @@ # VirtIO Driver for RT-Thread +[中文](README_zh.md) | English + ## Overview The VirtIO driver provides support for virtual I/O devices in RT-Thread, primarily used in virtualized environments like QEMU. @@ -43,17 +45,13 @@ Options: Enable individual VirtIO devices: -``` -RT-Thread Components → Device Drivers → Using VirtIO device drivers -``` - - `RT_USING_VIRTIO_BLK`: VirtIO block device support - `RT_USING_VIRTIO_NET`: VirtIO network device support - `RT_USING_VIRTIO_CONSOLE`: VirtIO console device support - `RT_USING_VIRTIO_GPU`: VirtIO GPU device support - `RT_USING_VIRTIO_INPUT`: VirtIO input device support -## Key Differences Between Legacy and Modern VirtIO +## Key Differences ### Legacy VirtIO (v0.95) - 32-bit feature negotiation @@ -66,7 +64,6 @@ RT-Thread Components → Device Drivers → Using VirtIO device drivers - Separate descriptor/driver/device queue areas - Enhanced status flow with FEATURES_OK check - Better memory alignment and atomicity guarantees -- Config generation field for atomic configuration reads ## Migration Guide @@ -94,74 +91,10 @@ The following BSPs have been updated to support both legacy and modern VirtIO: ## Reference Specifications -- [VirtIO Specification v1.0](https://docs.oasis-open.org/virtio/virtio/v1.0/virtio-v1.0.html) -- [VirtIO Specification v1.1](https://docs.oasis-open.org/virtio/virtio/v1.1/virtio-v1.1.html) -- [VirtIO Specification v1.2](https://docs.oasis-open.org/virtio/virtio/v1.2/virtio-v1.2.html) - -## Implementation Details - -### Feature Negotiation - -Modern VirtIO uses 64-bit feature negotiation: -- Device exposes features via `device_features` register (selected by `device_features_sel`) -- Driver acknowledges features via `driver_features` register (selected by `driver_features_sel`) -- For modern devices, the driver must negotiate `VIRTIO_F_VERSION_1` (feature bit 32) - -### Queue Initialization - -**Legacy VirtIO:** -- Uses single `queue_pfn` register pointing to the start of the queue area -- Guest page size configured via `guest_page_size` - -**Modern VirtIO:** -- Uses separate registers for descriptor, driver (avail), and device (used) areas: - - `queue_desc_low`/`queue_desc_high`: Descriptor table address - - `queue_driver_low`/`queue_driver_high`: Available ring address - - `queue_device_low`/`queue_device_high`: Used ring address -- Queue activated via `queue_ready` register - -### Status Flow - -**Modern VirtIO adds FEATURES_OK check:** -1. Reset device (status = 0) -2. Set ACKNOWLEDGE and DRIVER status bits -3. Read and negotiate features -4. Write negotiated features to device -5. Set FEATURES_OK status bit -6. Re-read status to verify FEATURES_OK (device may reject features) -7. If accepted, proceed with queue setup and set DRIVER_OK - -## Troubleshooting - -### Device Not Detected - -Check that: -1. QEMU is configured with VirtIO devices -2. The VirtIO version matches your QEMU configuration -3. The device memory region is correctly mapped - -### Build Errors - -Ensure: -1. The Kconfig is properly configured -2. All VirtIO header files are included -3. The BSP supports VirtIO (check `BSP_USING_VIRTIO`) - -### Runtime Issues - -Debug tips: -1. Check device version in MMIO config -2. Verify feature negotiation succeeded -3. Check queue initialization (descriptor, avail, used ring addresses) -4. Monitor interrupt status and acknowledgment - -## Contributing - -When adding new VirtIO devices or features: -1. Support both legacy and modern versions -2. Use the helper functions for feature negotiation (`virtio_get_features`, `virtio_set_features`) -3. Use version checking (`dev->version`) for version-specific code -4. Test on both legacy and modern QEMU configurations +- [VirtIO Specification v1.2](https://docs.oasis-open.org/virtio/virtio/v1.2/virtio-v1.2.html) (Latest, 2022) +- [VirtIO Specification v1.1](https://docs.oasis-open.org/virtio/virtio/v1.1/virtio-v1.1.html) (2019) +- [VirtIO Specification v1.0](https://docs.oasis-open.org/virtio/virtio/v1.0/virtio-v1.0.html) (2016) +- [OASIS VirtIO TC](https://www.oasis-open.org/committees/virtio/) ## License |