Hi sasha > -----Original Message----- > From: Sasha Levin <sashal@xxxxxxxxxx> > Sent: Tuesday, October 18, 2022 8:12 AM > To: linux-kernel@xxxxxxxxxxxxxxx; stable@xxxxxxxxxxxxxxx > Cc: Angus Chen <angus.chen@xxxxxxxxxxxxxxx>; Michael S . Tsirkin > <mst@xxxxxxxxxx>; Sasha Levin <sashal@xxxxxxxxxx>; jasowang@xxxxxxxxxx; > virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx > Subject: [PATCH AUTOSEL 4.9 8/8] virtio_pci: don't try to use intxif pin is zero > > From: Angus Chen <angus.chen@xxxxxxxxxxxxxxx> > > [ Upstream commit 71491c54eafa318fdd24a1f26a1c82b28e1ac21d ] > > The background is that we use dpu in cloud computing,the arch is x86,80 > cores. We will have a lots of virtio devices,like 512 or more. > When we probe about 200 virtio_blk devices,it will fail and > the stack is printed as follows: > > [25338.485128] virtio-pci 0000:b3:00.0: virtio_pci: leaving for legacy driver > [25338.496174] genirq: Flags mismatch irq 0. 00000080 (virtio418) vs. 00015a00 > (timer) > [25338.503822] CPU: 20 PID: 5431 Comm: kworker/20:0 Kdump: loaded Tainted: > G OE --------- - - 4.18.0-305.30.1.el8.x86_64 > [25338.516403] Hardware name: Inspur NF5280M5/YZMB-00882-10E, BIOS > 4.1.21 08/25/2021 > [25338.523881] Workqueue: events work_for_cpu_fn > [25338.528235] Call Trace: > [25338.530687] dump_stack+0x5c/0x80 > [25338.534000] __setup_irq.cold.53+0x7c/0xd3 > [25338.538098] request_threaded_irq+0xf5/0x160 > [25338.542371] vp_find_vqs+0xc7/0x190 > [25338.545866] init_vq+0x17c/0x2e0 [virtio_blk] > [25338.550223] ? ncpus_cmp_func+0x10/0x10 > [25338.554061] virtblk_probe+0xe6/0x8a0 [virtio_blk] > [25338.558846] virtio_dev_probe+0x158/0x1f0 > [25338.562861] really_probe+0x255/0x4a0 > [25338.566524] ? __driver_attach_async_helper+0x90/0x90 > [25338.571567] driver_probe_device+0x49/0xc0 > [25338.575660] bus_for_each_drv+0x79/0xc0 > [25338.579499] __device_attach+0xdc/0x160 > [25338.583337] bus_probe_device+0x9d/0xb0 > [25338.587167] device_add+0x418/0x780 > [25338.590654] register_virtio_device+0x9e/0xe0 > [25338.595011] virtio_pci_probe+0xb3/0x140 > [25338.598941] local_pci_probe+0x41/0x90 > [25338.602689] work_for_cpu_fn+0x16/0x20 > [25338.606443] process_one_work+0x1a7/0x360 > [25338.610456] ? create_worker+0x1a0/0x1a0 > [25338.614381] worker_thread+0x1cf/0x390 > [25338.618132] ? create_worker+0x1a0/0x1a0 > [25338.622051] kthread+0x116/0x130 > [25338.625283] ? kthread_flush_work_fn+0x10/0x10 > [25338.629731] ret_from_fork+0x1f/0x40 > [25338.633395] virtio_blk: probe of virtio418 failed with error -16 > > The log : > "genirq: Flags mismatch irq 0. 00000080 (virtio418) vs. 00015a00 (timer)" > was printed because of the irq 0 is used by timer exclusive,and when > vp_find_vqs call vp_find_vqs_msix and returns false twice (for > whatever reason), then it will call vp_find_vqs_intx as a fallback. > Because vp_dev->pci_dev->irq is zero, we request irq 0 with > flag IRQF_SHARED, and get a backtrace like above. > > According to PCI spec about "Interrupt Pin" Register (Offset 3Dh): > "The Interrupt Pin register is a read-only register that identifies the > legacy interrupt Message(s) the Function uses. Valid values are 01h, 02h, > 03h, and 04h that map to legacy interrupt Messages for INTA, > INTB, INTC, and INTD respectively. A value of 00h indicates that the > Function uses no legacy interrupt Message(s)." > > So if vp_dev->pci_dev->pin is zero, we should not request legacy > interrupt. > > Signed-off-by: Angus Chen <angus.chen@xxxxxxxxxxxxxxx> > Suggested-by: Michael S. Tsirkin <mst@xxxxxxxxxx> > Message-Id: <20220930000915.548-1-angus.chen@xxxxxxxxxxxxxxx> > Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> > --- > drivers/virtio/virtio_pci_common.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/virtio/virtio_pci_common.c > b/drivers/virtio/virtio_pci_common.c > index 37e3ba5dadf6..d634eb926a2f 100644 > --- a/drivers/virtio/virtio_pci_common.c > +++ b/drivers/virtio/virtio_pci_common.c > @@ -389,6 +389,9 @@ int vp_find_vqs(struct virtio_device *vdev, unsigned > nvqs, > true, false); > if (!err) > return 0; > + /* Is there an interrupt pin? If not give up. */ > + if (!(to_vp_device(vdev)->pci_dev->pin)) > + return err; > /* Finally fall back to regular interrupts. */ > return vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names, > false, false); > -- > 2.35.1 the patch 71491c54eafa31 has been fixed by 2145ab513e3b3, It is report by Michael Ellerman <mpe@xxxxxxxxxxxxxx> and suggested by linus. If it is merged in the stable git repo, I worry about powerpc arch. Thans.
