On Mon, Apr 15, 2024 at 6:41 PM Cindy Lu <l...@redhat.com> wrote:
>
> On Mon, Apr 15, 2024 at 5:34 PM Michael S. Tsirkin <m...@redhat.com> wrote:
> >
> > From: Cindy Lu <l...@redhat.com>
> >
> > During the booting process of the non-standard image, the behavior of the
> > called function in qemu is as follows:
> >
> > 1. vhost_net_stop() was triggered by guest image. This will call the
> > function
> > virtio_pci_set_guest_notifiers() with assgin= false,
> > virtio_pci_set_guest_notifiers(） will release the irqfd for vector 0
> >
> > 2. virtio_reset() was triggered, this will set configure vector to
> > VIRTIO_NO_VECTOR
> >
> > 3.vhost_net_start() was called (at this time, the configure vector is
> > still VIRTIO_NO_VECTOR) and then call virtio_pci_set_guest_notifiers() with
> > assgin=true, so the irqfd for vector 0 is still not "init" during this
> > process
> >
> > 4. The system continues to boot and sets the vector back to 0. After that
> > msix_fire_vector_notifier() was triggered to unmask the vector 0 and meet
> > the crash
> >
> > To fix the issue, we need to support changing the vector after
> > VIRTIO_CONFIG_S_DRIVER_OK is set.
> >
> > (gdb) bt
> > 0 __pthread_kill_implementation (threadid=<optimized out>,
> > signo=signo@entry=6, no_tid=no_tid@entry=0)
> > at pthread_kill.c:44
> > 1 0x00007fc87148ec53 in __pthread_kill_internal (signo=6,
> > threadid=<optimized out>) at pthread_kill.c:78
> > 2 0x00007fc87143e956 in __GI_raise (sig=sig@entry=6) at
> > ../sysdeps/posix/raise.c:26
> > 3 0x00007fc8714287f4 in __GI_abort () at abort.c:79
> > 4 0x00007fc87142871b in __assert_fail_base
> > (fmt=0x7fc8715bbde0 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n",
> > assertion=0x5606413efd53 "ret == 0", file=0x5606413ef87d
> > "../accel/kvm/kvm-all.c", line=1837, function=<optimized out>) at
> > assert.c:92
> > 5 0x00007fc871437536 in __GI___assert_fail
> > (assertion=0x5606413efd53 "ret == 0", file=0x5606413ef87d
> > "../accel/kvm/kvm-all.c", line=1837, function=0x5606413f06f0
> > <__PRETTY_FUNCTION__.19> "kvm_irqchip_commit_routes") at assert.c:101
> > 6 0x0000560640f884b5 in kvm_irqchip_commit_routes (s=0x560642cae1f0) at
> > ../accel/kvm/kvm-all.c:1837
> > 7 0x0000560640c98f8e in virtio_pci_one_vector_unmask
> > (proxy=0x560643c65f00, queue_no=4294967295, vector=0, msg=...,
> > n=0x560643c6e4c8)
> > at ../hw/virtio/virtio-pci.c:1005
> > 8 0x0000560640c99201 in virtio_pci_vector_unmask (dev=0x560643c65f00,
> > vector=0, msg=...)
> > at ../hw/virtio/virtio-pci.c:1070
> > 9 0x0000560640bc402e in msix_fire_vector_notifier (dev=0x560643c65f00,
> > vector=0, is_masked=false)
> > at ../hw/pci/msix.c:120
> > 10 0x0000560640bc40f1 in msix_handle_mask_update (dev=0x560643c65f00,
> > vector=0, was_masked=true)
> > at ../hw/pci/msix.c:140
> > 11 0x0000560640bc4503 in msix_table_mmio_write (opaque=0x560643c65f00,
> > addr=12, val=0, size=4)
> > at ../hw/pci/msix.c:231
> > 12 0x0000560640f26d83 in memory_region_write_accessor
> > (mr=0x560643c66540, addr=12, value=0x7fc86b7bc628, size=4, shift=0,
> > mask=4294967295, attrs=...)
> > at ../system/memory.c:497
> > 13 0x0000560640f270a6 in access_with_adjusted_size
> >
> > (addr=12, value=0x7fc86b7bc628, size=4, access_size_min=1,
> > access_size_max=4, access_fn=0x560640f26c8d <memory_region_write_accessor>,
> > mr=0x560643c66540, attrs=...) at ../system/memory.c:573
> > 14 0x0000560640f2a2b5 in memory_region_dispatch_write (mr=0x560643c66540,
> > addr=12, data=0, op=MO_32, attrs=...)
> > at ../system/memory.c:1521
> > 15 0x0000560640f37bac in flatview_write_continue
> > (fv=0x7fc65805e0b0, addr=4273803276, attrs=..., ptr=0x7fc871e9c028,
> > len=4, addr1=12, l=4, mr=0x560643c66540)
> > at ../system/physmem.c:2714
> > 16 0x0000560640f37d0f in flatview_write
> > (fv=0x7fc65805e0b0, addr=4273803276, attrs=..., buf=0x7fc871e9c028,
> > len=4) at ../system/physmem.c:2756
> > 17 0x0000560640f380bf in address_space_write
> > (as=0x560642161ae0 <address_space_memory>, addr=4273803276, attrs=...,
> > buf=0x7fc871e9c028, len=4)
> > at ../system/physmem.c:2863
> > 18 0x0000560640f3812c in address_space_rw
> > (as=0x560642161ae0 <address_space_memory>, addr=4273803276, attrs=...,
> > buf=0x7fc871e9c028, len=4, is_write=true) at ../system/physmem.c:2873
> > --Type <RET> for more, q to quit, c to continue without paging--
> > 19 0x0000560640f8aa55 in kvm_cpu_exec (cpu=0x560642f205e0) at
> > ../accel/kvm/kvm-all.c:2915
> > 20 0x0000560640f8d731 in kvm_vcpu_thread_fn (arg=0x560642f205e0) at
> > ../accel/kvm/kvm-accel-ops.c:51
> > 21 0x00005606411949f4 in qemu_thread_start (args=0x560642f292b0) at
> > ../util/qemu-thread-posix.c:541
> > 22 0x00007fc87148cdcd in start_thread (arg=<optimized out>) at
> > pthread_create.c:442
> > 23 0x00007fc871512630 in clone3 () at
> > ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81
> > (gdb)
> >
> > MST: coding style and typo fixups
> >
> > Fixes: f9a09ca3ea ("vhost: add support for configure interrupt")
> > Cc: qemu-sta...@nongnu.org
> > Signed-off-by: Cindy Lu <l...@redhat.com>
> > Message-Id: <20240412062750.475180-1-l...@redhat.com>
> > Reviewed-by: Michael S. Tsirkin <m...@redhat.com>
> > Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
> > Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
> > ---
> > hw/virtio/virtio-pci.c | 37 +++++++++++++++++++++++++++++++++++--
> > 1 file changed, 35 insertions(+), 2 deletions(-)
> >
> > v7->v8:
> > more cleanups, suggested by Philip
> >
> > still untested, i just got involved to help address coding style
> > issues
> >
> qtest and sanity test are all passed
>
> Tested-by: Cindy Lu <l...@redhat.com>
Btw, in the future, it would be better to have a dedicated qtest to
test MSI-X confugation after DRIVER_OK.
Thanks
>
> > diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> > index cb6940fc0e..cb159fd078 100644
> > --- a/hw/virtio/virtio-pci.c
> > +++ b/hw/virtio/virtio-pci.c
> > @@ -1424,6 +1424,38 @@ static int virtio_pci_add_mem_cap(VirtIOPCIProxy
> > *proxy,
> > return offset;
> > }
> >
> > +static void virtio_pci_set_vector(VirtIODevice *vdev,
> > + VirtIOPCIProxy *proxy,
> > + int queue_no, uint16_t old_vector,
> > + uint16_t new_vector)
> > +{
> > + bool kvm_irqfd = (vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) &&
> > + msix_enabled(&proxy->pci_dev) && kvm_msi_via_irqfd_enabled();
> > +
> > + if (new_vector == old_vector) {
> > + return;
> > + }
> > +
> > + /*
> > + * If the device uses irqfd and the vector changes after DRIVER_OK is
> > + * set, we need to release the old vector and set up the new one.
> > + * Otherwise just need to set the new vector on the device.
> > + */
> > + if (kvm_irqfd && old_vector != VIRTIO_NO_VECTOR) {
> > + kvm_virtio_pci_vector_release_one(proxy, queue_no);
> > + }
> > + /* Set the new vector on the device. */
> > + if (queue_no == VIRTIO_CONFIG_IRQ_IDX) {
> > + vdev->config_vector = new_vector;
> > + } else {
> > + virtio_queue_set_vector(vdev, queue_no, new_vector);
> > + }
> > + /* If the new vector changed need to set it up. */
> > + if (kvm_irqfd && new_vector != VIRTIO_NO_VECTOR) {
> > + kvm_virtio_pci_vector_use_one(proxy, queue_no);
> > + }
> > +}
> > +
> > int virtio_pci_add_shm_cap(VirtIOPCIProxy *proxy,
> > uint8_t bar, uint64_t offset, uint64_t length,
> > uint8_t id)
> > @@ -1570,7 +1602,8 @@ static void virtio_pci_common_write(void *opaque,
> > hwaddr addr,
> > } else {
> > val = VIRTIO_NO_VECTOR;
> > }
> > - vdev->config_vector = val;
> > + virtio_pci_set_vector(vdev, proxy, VIRTIO_CONFIG_IRQ_IDX,
> > + vdev->config_vector, val);
> > break;
> > case VIRTIO_PCI_COMMON_STATUS:
> > if (!(val & VIRTIO_CONFIG_S_DRIVER_OK)) {
> > @@ -1610,7 +1643,7 @@ static void virtio_pci_common_write(void *opaque,
> > hwaddr addr,
> > } else {
> > val = VIRTIO_NO_VECTOR;
> > }
> > - virtio_queue_set_vector(vdev, vdev->queue_sel, val);
> > + virtio_pci_set_vector(vdev, proxy, vdev->queue_sel, vector, val);
> > break;
> > case VIRTIO_PCI_COMMON_Q_ENABLE:
> > if (val == 1) {
> > --
> > MST
> >
>
