CV-Bowen opened a new pull request, #18491:
URL: https://github.com/apache/nuttx/pull/18491
## Summary
Add support for `VIRTIO_RPMSG_F_BUFADDR` feature bit in rpmsg virtio,
allowing the host and remote sides to specify buffer physical addresses through
the resource table config space.
In some multi-core systems, the shared memory pool needs to be split into
separate regions for host-to-remote and remote-to-host buffers. This is useful
when the TX and RX buffers must reside at specific physical addresses (e.g.,
different memory banks or regions with different cache/access attributes). The
`VIRTIO_RPMSG_F_BUFADDR` feature allows this configuration to be communicated
through the standard resource table mechanism.
## Impact
- No impact on existing configurations — the feature is only activated when
both sides negotiate `VIRTIO_RPMSG_F_BUFADDR`
- Backward compatible: the reserved field shrinks but total struct size is
preserved via PACKED layout
- No breaking changes to existing rpmsg virtio users
## Testing
Build test with `qemu-armv8a:v8a_server` and `qemu-armv8a:v8a_proxy`
configurations:
```bash
cmake -B cmake_out/v8a_server -DBOARD_CONFIG=qemu-armv8a:v8a_server -GNinja
cmake --build cmake_out/v8a_server
cmake -B cmake_out/v8a_proxy -DBOARD_CONFIG=qemu-armv8a:v8a_proxy -GNinja
cmake --build cmake_out/v8a_proxy
```
```log
❯ qemu-system-aarch64 -cpu cortex-a53 -nographic \
-machine virt,virtualization=on,gic-version=3 \
-chardev stdio,id=con,mux=on -serial chardev:con \
-object
memory-backend-file,discard-data=on,id=shmmem-shmem0,mem-path=/dev/shm/my_shmem0,size=4194304,share=yes
\
-device ivshmem-plain,id=shmem0,memdev=shmmem-shmem0,addr=0xb \
-device virtio-serial-device,bus=virtio-mmio-bus.0 \
-chardev socket,path=/tmp/rpmsg_port_uart_socket,server=on,wait=off,id=foo \
-device virtconsole,chardev=foo \
-mon chardev=con,mode=readline -kernel ./cmake_out/v8a_server/nuttx \
-gdb tcp::7775
[ 0.000000] [ 0] [ INFO] [server] pci_register_rptun_ivshmem_driver:
Register ivshmem driver, id=0, cpuname=proxy, master=1
[ 0.000000] [ 3] [ INFO] [server] pci_scan_bus: pci_scan_bus for bus 0
[ 0.000000] [ 3] [ INFO] [server] pci_scan_bus: class = 00000600,
hdr_type = 00000000
[ 0.000000] [ 3] [ INFO] [server] pci_scan_bus: 00:00 [1b36:0008]
[ 0.000000] [ 3] [ INFO] [server] pci_setup_device: pbar0 set bad mask
[ 0.000000] [ 3] [ INFO] [server] pci_setup_device: pbar1 set bad mask
[ 0.000000] [ 3] [ INFO] [server] pci_setup_device: pbar2 set bad mask
[ 0.000000] [ 3] [ INFO] [server] pci_setup_device: pbar3 set bad mask
[ 0.000000] [ 3] [ INFO] [server] pci_setup_device: pbar4 set bad mask
[ 0.000000] [ 3] [ INFO] [server] pci_setup_device: pbar5 set bad mask
[ 0.000000] [ 3] [ INFO] [server] pci_scan_bus: class = 00000200,
hdr_type = 00000000
[ 0.000000] [ 3] [ INFO] [server] pci_scan_bus: 00:08 [1af4:1000]
[ 0.000000] [ 3] [ INFO] [server] pci_setup_device: pbar0:
mask64=fffffffe 32bytes
[ 0.000000] [ 3] [ INFO] [server] pci_setup_device: pbar1:
mask64=fffffff0 4096bytes
[ 0.000000] [ 3] [ INFO] [server] pci_setup_device: pbar2 set bad mask
[ 0.000000] [ 3] [ INFO] [server] pci_setup_device: pbar3 set bad mask
[ 0.000000] [ 3] [ INFO] [server] pci_setup_device: pbar4:
mask64=fffffffffffffff0 16384bytes
[ 0.000000] [ 3] [ INFO] [server] pci_scan_bus: class = 00000500,
hdr_type = 00000000
[ 0.000000] [ 3] [ INFO] [server] pci_scan_bus: 00:58 [1af4:1110]
[ 0.000000] [ 3] [ INFO] [server] pci_setup_device: pbar0:
mask64=fffffff0 256bytes
[ 0.000000] [ 3] [ INFO] [server] pci_setup_device: pbar1 set bad mask
[ 0.000000] [ 3] [ INFO] [server] pci_setup_device: pbar2:
mask64=fffffffffffffff0 4194304bytes
[ 0.000000] [ 3] [ INFO] [server] pci_setup_device: pbar4 set bad mask
[ 0.000000] [ 3] [ INFO] [server] pci_setup_device: pbar5 set bad mask
[ 0.000000] [ 3] [ INFO] [server] ivshmem_probe: shmem addr=0x8000400000
size=4194304 reg=0x10001000
[ 0.000000] [ 3] [ INFO] [server] rptun_ivshmem_probe: shmem
addr=0x8000400000 size=4194304
NuttShell (NSH) NuttX-12.12.0
server> [ 0.000000] [ 0] [ INFO] [proxy]
pci_register_rptun_ivshmem_driver: Register ivshmem driver, id=0,
cpuname=server, master=0
[ 0.000000] [ 3] [ INFO] [proxy] pci_scan_bus: pci_scan_bus for bus 0
[ 0.000000] [ 3] [ INFO] [proxy] pci_scan_bus: class = 00000600,
hdr_type = 00000000
[ 0.000000] [ 3] [ INFO] [proxy] pci_scan_bus: 00:00 [1b36:0008]
[ 0.000000] [ 3] [ INFO] [proxy] pci_setup_device: pbar0 set bad mask
[ 0.000000] [ 3] [ INFO] [proxy] pci_setup_device: pbar1 set bad mask
[ 0.000000] [ 3] [ INFO] [proxy] pci_setup_device: pbar2 set bad mask
[ 0.000000] [ 3] [ INFO] [proxy] pci_setup_device: pbar3 set bad mask
[ 0.000000] [ 3] [ INFO] [proxy] pci_setup_device: pbar4 set bad mask
[ 0.000000] [ 3] [ INFO] [proxy] pci_setup_device: pbar5 set bad mask
[ 0.000000] [ 3] [ INFO] [proxy] pci_scan_bus: class = 00000200,
hdr_type = 00000000
[ 0.000000] [ 3] [ INFO] [proxy] pci_scan_bus: 00:08 [1af4:1000]
[ 0.000000] [ 3] [ INFO] [proxy] pci_setup_device: pbar0:
mask64=fffffffe 32bytes
[ 0.000000] [ 3] [ INFO] [proxy] pci_setup_device: pbar1:
mask64=fffffff0 4096bytes
[ 0.000000] [ 3] [ INFO] [proxy] pci_setup_device: pbar2 set bad mask
[ 0.000000] [ 3] [ INFO] [proxy] pci_setup_device: pbar3 set bad mask
[ 0.000000] [ 3] [ INFO] [proxy] pci_setup_device: pbar4:
mask64=fffffffffffffff0 16384bytes
[ 0.000000] [ 3] [ INFO] [proxy] pci_scan_bus: class = 00000500,
hdr_type = 00000000
[ 0.000000] [ 3] [ INFO] [proxy] pci_scan_bus: 00:58 [1af4:1110]
[ 0.000000] [ 3] [ INFO] [proxy] pci_setup_device: pbar0:
mask64=fffffff0 256bytes
[ 0.000000] [ 3] [ INFO] [proxy] pci_setup_device: pbar1 set bad mask
[ 0.000000] [ 3] [ INFO] [proxy] pci_setup_device: pbar2:
mask64=fffffffffffffff0 4194304bytes
[ 0.000000] [ 3] [ INFO] [proxy] pci_setup_device: pbar4 set bad mask
[ 0.000000] [ 3] [ INFO] [proxy] pci_setup_device: pbar5 set bad mask
[ 0.000000] [ 3] [ INFO] [proxy] ivshmem_probe: shmem addr=0x8000400000
size=4194304 reg=0x10001000
[ 0.000000] [ 3] [ INFO] [proxy] rptun_ivshmem_probe: shmem
addr=0x8000400000 size=4194304
[ 0.000000] [ 3] [ INFO] [proxy] rptun_ivshmem_probe: Start the wdog
server>
server>
server>
server> rpmsg ping all 1 1 1 1
[ 14.991300] [ 7] [ EMERG] [server] ping times: 1
[ 14.992000] [ 7] [ EMERG] [server] buffer_len: 1520, send_len: 17
[ 14.993500] [ 7] [ EMERG] [server] avg: 0 s, 92999840 ns
[ 14.994500] [ 7] [ EMERG] [server] min: 0 s, 92999840 ns
[ 14.995400] [ 7] [ EMERG] [server] max: 0 s, 92999840 ns
[ 14.996600] [ 7] [ EMERG] [server] rate: 0.001462 Mbits/sec
[ 15.004500] [ 7] [ EMERG] [server] ping times: 1
[ 15.005200] [ 7] [ EMERG] [server] buffer_len: 2008, send_len: 17
[ 15.006200] [ 7] [ EMERG] [server] avg: 0 s, 77037968 ns
[ 15.007100] [ 7] [ EMERG] [server] min: 0 s, 77037968 ns
[ 15.008000] [ 7] [ EMERG] [server] max: 0 s, 77037968 ns
[ 15.008900] [ 7] [ EMERG] [server] rate: 0.001765 Mbits/sec
server>
server> uname -a
NuttX server 12.12.0 e9cf314c221-dirty Mar 4 2026 20:27:46 arm64 qemu-armv8a
server> rpmsg dump all
[ 18.381900] [ 7] [ EMERG] [server] Local: server Remote: proxy Headrx 8
[ 18.384300] [ 7] [ EMERG] [server] Dump rpmsg info between cpu (master:
yes)server <==> proxy:
[ 18.385800] [ 7] [ EMERG] [server] rpmsg vq RX:
[ 18.387000] [ 7] [ EMERG] [server] VQ: rx_vq - size=8; free=0; queued=0;
desc_head_idx=32768; available_idx=0; avail.idx=16; used_cons_idx=8;
used.idx=8; avail.flags=0x0; used.flags=0x1
[ 18.389800] [ 7] [ EMERG] [server] rpmsg vq TX:
[ 18.390500] [ 7] [ EMERG] [server] VQ: tx_vq - size=8; free=6; queued=0;
desc_head_idx=2; available_idx=0; avail.idx=6; used_cons_idx=4; used.idx=6;
avail.flags=0x1; used.flags=0x0
[ 18.393100] [ 7] [ EMERG] [server] rpmsg ept list:
[ 18.394200] [ 7] [ EMERG] [server] ept NS
[ 18.394900] [ 7] [ EMERG] [server] ept rpmsg-sensor
[ 18.395700] [ 7] [ EMERG] [server] ept rpmsg-ping
[ 18.396500] [ 7] [ EMERG] [server] ept rpmsg-syslog
[ 18.397300] [ 7] [ EMERG] [server] rpmsg buffer list:
[ 18.398600] [ 7] [ EMERG] [server] RX buffer, total 8, pending 0
[ 18.400300] [ 7] [ EMERG] [server] TX buffer, total 8, pending 0
[ 18.403100] [ 7] [ EMERG] [server] Remote: proxy2 state: 1
[ 18.404200] [ 7] [ EMERG] [server] ept NS
[ 18.404900] [ 7] [ EMERG] [server] ept rpmsg-sensor
[ 18.405700] [ 7] [ EMERG] [server] ept rpmsg-ping
[ 18.406600] [ 7] [ EMERG] [server] rpmsg_port queue RX: {used: 0, avail:
8}
[ 18.406600] [ 7] [ EMERG] [server] rpmsg buffer list:
[ 18.408800] [ 7] [ EMERG] [server] rpmsg_port queue TX: {used: 0, avail:
8}
[ 18.408800] [ 7] [ EMERG] [server] rpmsg buffer list:
[ 18.413600] [ 7] [ ALERT] [server] sched_dumpstack: backtrace| 5:
0x00000000402a8a20 0x00000000402aa4e8 0x000000004029c1c8 0x000000004028cc54
0x00000000402e4328 0x00000000402e43d8 0x00000000402bd054 0x00000000402bd4dc
[ 18.416500] [ 7] [ ALERT] [server] sched_dumpstack: backtrace| 5:
0x00000000402ad390
[ 18.418300] [ 7] [ ALERT] [server] sched_dumpstack: backtrace| 6:
0x00000000402a8e40 0x00000000402f6474 0x00000000402bc428 0x00000000402bd5c4
0x00000000402ad390
server>
```
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