Hi Bin,
On Fri, 7 Sep 2018 09:49:24 +0800 Bin Meng bmeng.cn@gmail.com wrote:
Hi Tuomas,
On Fri, Sep 7, 2018 at 5:03 AM Tuomas Tynkkynen tuomas.tynkkynen@iki.fi wrote:
Hi Bin,
On 09/04/2018 12:31 PM, Bin Meng wrote:
Hi Lukas,
On Tue, Sep 4, 2018 at 5:39 AM Auer, Lukas lukas.auer@aisec.fraunhofer.de wrote:
On Thu, 2018-08-30 at 00:54 -0700, Bin Meng wrote:
This adds QEMU RISC-V 'virt' board target support, with the hope of helping people easily test U-Boot on RISC-V.
The QEMU virt machine models a generic RISC-V virtual machine with support for the VirtIO standard networking and block storage devices. It has CLINT, PLIC, 16550A UART devices in addition to VirtIO and it also uses device-tree to pass configuration information to guest software. It implements RISC-V privileged architecture spec v1.10.
Both 32-bit and 64-bit builds are supported. Support is pretty much preliminary, only booting to U-Boot shell with the UART driver on a single core. Booting Linux is not supported yet.
For your information and to avoid duplicate work, I am working on a patch set that improves RISC-V support in u-boot. I am currently able to boot Linux on a multi-core setup in QEMU, but they are not quite ready to submit yet.
This is great! My next step is to work on virtio driver support in U-Boot as qemu-riscv virt machine has these devices but we don't have corresponding drivers in U-Boot.
At some point I was working on porting the virtio stack from Linux to U-Boot and IIRC got virtio-blk and virtio-net working on ARM. But other things consumed my time and I never quite finished that work. Let me know if you want to take a look.
This is great. I just finished reading the virtio 1.0 spec and was about to start the work. My interest was to add virtio-blk and virtio-net driver to U-Boot too since they are most common devices (others are not used too much I believe). If you already have the drivers working, I can help to bring them upstream.
You can find my branch here:
https://github.com/dezgeg/u-boot/tree/virtio
It should work under qemu_arm64_defconfig as follows:
qemu-system-aarch64 -machine virt -cpu cortex-a57 -m 512 \ -bios u-boot.bin -s -nographic \ -netdev user,id=net0 -device virtio-net-device,netdev=net0 \ -drive if=none,file=disk.img,id=disk0 \ -device virtio-blk-device,drive=disk0
I tried with Fedora-Server-netinst-aarch64-28-1.1.iso I had lying around and letting it auto-boot worked fine.
Also interrupting the boot and doing 'virtio scan; dhcp' gets a successful DHCP lease from QEMU's internal server.
I took a brief look and these things still need work:
- Some of the virtio headers imported verbatim cause compiler warnings because we don't disable strict aliasing.
- Architectures need to import various definitions from Linux. At least PAGE_SIZE & PAGE_SHIFT and wmb() & rmb(). (currently there are just gross hacks around this)
- Feature negotiation (needed for virtio-net to be able to set/get a MAC address) is not implemented yet.
- The virtio-pci transport is not implemented, only virtio-mmio.
- Error handling is missing in many places.
- Resource cleanup in some places, like virtio-net which needs to remove live buffers from the RX virtqueue on shutdown and I haven't looked into how to do that.
- Lots of small things like removing debug/commented out code, wrong kerneldoc comments, dead/uneeded code etc. to be cleaned up.
Have fun and let me know if you have questions.
- Tuomas