Hi Mathieu, On Wed, Jun 29, 2022 at 11:13 PM Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> wrote: > > Hi Anup, > > On Wed, Jun 08, 2022 at 10:43:34PM +0530, Anup Patel wrote: > > The rpmsg_probe() is broken at the moment because virtqueue_add_inbuf() > > fails due to both virtqueues (Rx and Tx) marked as broken by the > > __vring_new_virtqueue() function. To solve this, virtio_device_ready() > > (which unbreaks queues) should be called before virtqueue_add_inbuf(). > > > > Fixes: 8b4ec69d7e09 ("virtio: harden vring IRQ") > > Signed-off-by: Anup Patel <apatel@xxxxxxxxxxxxxxxx> > > --- > > drivers/rpmsg/virtio_rpmsg_bus.c | 6 +++--- > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c > > index 905ac7910c98..71a64d2c7644 100644 > > --- a/drivers/rpmsg/virtio_rpmsg_bus.c > > +++ b/drivers/rpmsg/virtio_rpmsg_bus.c > > @@ -929,6 +929,9 @@ static int rpmsg_probe(struct virtio_device *vdev) > > /* and half is dedicated for TX */ > > vrp->sbufs = bufs_va + total_buf_space / 2; > > > > + /* From this point on, we can notify and get callbacks. */ > > + virtio_device_ready(vdev); > > + > > Calling virtio_device_ready() here means that virtqueue_get_buf_ctx_split() can > potentially be called (by way of rpmsg_recv_done()), which will race with > virtqueue_add_inbuf(). If buffers in the virtqueue aren't available then > rpmsg_recv_done() will fail, potentially breaking remote processors' state > machines that don't expect their initial name service to fail when the "device" > has been marked as ready. We have VirtIO RPMSG available for Xvisor Guest/VM. When I run Linux-5.19-rcX as Xvisor Guest/VM, I get following warning for every call to virtqueue_add_inbuf(): [guest0/uart0] [ 2.147931] ------------[ cut here ]------------ [guest0/uart0] [ 2.166242] WARNING: CPU: 0 PID: 1 at drivers/rpmsg/virtio_rpmsg_bus.c:941 rpmsg_probe+0x2e6/0x39e [guest0/uart0] [ 2.190337] Modules linked in: [guest0/uart0] [ 2.196514] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.19.0-rc4 #1 [guest0/uart0] [ 2.222706] Hardware name: Virt64 (DT) [guest0/uart0] [ 2.231712] epc : rpmsg_probe+0x2e6/0x39e [guest0/uart0] [ 2.243443] ra : rpmsg_probe+0x1f8/0x39e [guest0/uart0] [ 2.256899] epc : ffffffff804f7b2c ra : ffffffff804f7a3e sp : ff2000000400b870 [guest0/uart0] [ 2.277700] gp : ffffffff810dc5b8 tp : ff60000001258000 t0 : ff2000000400b888 [guest0/uart0] [ 2.293144] t1 : 0000000000000008 t2 : 0000000000000040 s0 : ff2000000400b910 [guest0/uart0] [ 2.318932] s1 : ff600000012cde00 a0 : fffffffffffffffb a1 : ff2000000400b858 [guest0/uart0] [ 2.339688] a2 : 0000000000000001 a3 : 0000000000000000 a4 : 0000000000000001 [guest0/uart0] [ 2.361387] a5 : 0000000000000000 a6 : 0000000000000000 a7 : 0000000000000cc0 [guest0/uart0] [ 2.396055] s2 : ff60000003a00000 s3 : 0000000000000000 s4 : ff600000015ad428 [guest0/uart0] [ 2.414673] s5 : 0000000000000000 s6 : 0000000000000cc0 s7 : ff60000003a00000 [guest0/uart0] [ 2.439996] s8 : ffffffff80d91408 s9 : 0000000000040000 s10: ffffffff808000ac [guest0/uart0] [ 2.463539] s11: 0000000000000000 t3 : ff6000000fb4f000 t4 : ffffffffffffffff [guest0/uart0] [ 2.484201] t5 : 0000000000000000 t6 : ff600000025a20c4 [guest0/uart0] [ 2.500229] status: 0000000200000120 badaddr: 0000000000000000 cause: 0000000000000003 [guest0/uart0] [ 2.522769] [<ffffffff80374032>] virtio_dev_probe+0x162/0x2e6 [guest0/uart0] [ 2.544173] [<ffffffff803b57a8>] really_probe.part.0+0x56/0x1ec [guest0/uart0] [ 2.574984] [<ffffffff803b59ae>] __driver_probe_device+0x70/0xde [guest0/uart0] [ 2.596610] [<ffffffff803b5a48>] driver_probe_device+0x2c/0xb0 [guest0/uart0] [ 2.612964] [<ffffffff803b5f70>] __device_attach_driver+0x62/0x9a [guest0/uart0] [ 2.640715] [<ffffffff803b3b78>] bus_for_each_drv+0x4c/0x8a [guest0/uart0] [ 2.659895] [<ffffffff803b5c7a>] __device_attach+0x96/0x17a [guest0/uart0] [ 2.679809] [<ffffffff803b60be>] device_initial_probe+0xe/0x16 [guest0/uart0] [ 2.696944] [<ffffffff803b4b80>] bus_probe_device+0x7c/0x82 [guest0/uart0] [ 2.720666] [<ffffffff803b2aec>] device_add+0x2da/0x6be [guest0/uart0] [ 2.743288] [<ffffffff80373e4e>] register_virtio_device+0x192/0x214 [guest0/uart0] [ 2.765431] [<ffffffff80378048>] virtio_mmio_probe+0x134/0x1f2 [guest0/uart0] [ 2.795974] [<ffffffff803b77f2>] platform_probe+0x4e/0x96 [guest0/uart0] [ 2.816947] [<ffffffff803b57a8>] really_probe.part.0+0x56/0x1ec [guest0/uart0] [ 2.832840] [<ffffffff803b59ae>] __driver_probe_device+0x70/0xde [guest0/uart0] [ 2.854298] [<ffffffff803b5a48>] driver_probe_device+0x2c/0xb0 [guest0/uart0] [ 2.874422] [<ffffffff803b6008>] __driver_attach+0x60/0x108 [guest0/uart0] [ 2.897804] [<ffffffff803b3af2>] bus_for_each_dev+0x4a/0x84 [guest0/uart0] [ 2.927286] [<ffffffff803b522e>] driver_attach+0x1a/0x22 [guest0/uart0] [ 2.957400] [<ffffffff803b4d9e>] bus_add_driver+0x12c/0x196 [guest0/uart0] [ 2.977573] [<ffffffff803b677a>] driver_register+0x48/0xdc [guest0/uart0] [ 3.001172] [<ffffffff803b7564>] __platform_driver_register+0x1c/0x24 [guest0/uart0] [ 3.028986] [<ffffffff8081c11c>] virtio_mmio_init+0x1a/0x22 [guest0/uart0] [ 3.047038] [<ffffffff800020dc>] do_one_initcall+0x38/0x174 [guest0/uart0] [ 3.071633] [<ffffffff80800fca>] kernel_init_freeable+0x1a6/0x20a [guest0/uart0] [ 3.095840] [<ffffffff80652d04>] kernel_init+0x1e/0x10a [guest0/uart0] [ 3.120816] [<ffffffff800032dc>] ret_from_exception+0x0/0xc [guest0/uart0] [ 3.143400] ---[ end trace 0000000000000000 ]--- I am not claiming that this patch does the right thing but with this patch VirtIO RPmsg starts working again for me on Xvisor Guest/VM. Upon further investigation, it seems this warning is because of a recent kernel commit mentioned in the "Fixes: " tag. Looks like with latest 5.19-rcX, we can't call virtqueue_add_inbuf() until virtqueue is marked as unbroken by virtio_device_ready(). Regards, Anup > > What does make me curious though is that nobody on the remoteproc mailing list > has complained about commit 8b4ec69d7e09 breaking their environment... By now, > i.e rc4, that should have happened. Anyone from TI, ST and Xilinx care to test this on > their rig? > > Thanks, > Mathieu > > > /* set up the receive buffers */ > > for (i = 0; i < vrp->num_bufs / 2; i++) { > > struct scatterlist sg; > > @@ -983,9 +986,6 @@ static int rpmsg_probe(struct virtio_device *vdev) > > */ > > notify = virtqueue_kick_prepare(vrp->rvq); > > > > - /* From this point on, we can notify and get callbacks. */ > > - virtio_device_ready(vdev); > > - > > /* tell the remote processor it can start sending messages */ > > /* > > * this might be concurrent with callbacks, but we are only > > -- > > 2.34.1 > >