similar to: [PATCH 1/6] virtio_pci: minor MSI-X cleanups

This refactors find_vqs, making it more readable and robust, and fixing two regressions from 2.6.30: - double free_irq causing BUG_ON on device removal - probe failure when vq can't be assigned to msi-x vector (reported on old host kernels) An older version of this patch was tested by Amit Shah. Reported-by: Amit Shah <amit.shah at redhat.com> Signed-off-by: Michael S. Tsirkin

This refactors find_vqs, making it more readable and robust, and fixing two regressions from 2.6.30: - double free_irq causing BUG_ON on device removal - probe failure when vq can't be assigned to msi-x vector (reported on old host kernels) An older version of this patch was tested by Amit Shah. Reported-by: Amit Shah <amit.shah at redhat.com> Signed-off-by: Michael S. Tsirkin

This refactors find_vqs, making it more readable and robust, and fixing two regressions from 2.6.30: - double free_irq causing BUG_ON on device removal - probe failure when vq can't be assigned to msi-x vector (reported on old host kernels) An older version of this patch was tested by Amit Shah. Reported-by: Amit Shah <amit.shah at redhat.com> Signed-off-by: Michael S. Tsirkin

This refactors find_vqs, making it more readable and robust, and fixing two regressions from 2.6.30: - double free_irq causing BUG_ON on device removal - probe failure when vq can't be assigned to msi-x vector (reported on old host kernels) An older version of this patch was tested by Amit Shah. Reported-by: Amit Shah <amit.shah at redhat.com> Signed-off-by: Michael S. Tsirkin

virtio currently fails to find any vqs if the device supports msi-x but fails to assign it to a queue. Turns out, this actually happens for old host kernels which can't allocate a gsi for the vector. As a result guest does not use virtio net. Fix this by retrying with less vectors and finally disabling msi on such failures and falling back on regular interrupts. Reported-by: Amit Shah

virtio currently fails to find any vqs if the device supports msi-x but fails to assign it to a queue. Turns out, this actually happens for old host kernels which can't allocate a gsi for the vector. As a result guest does not use virtio net. Fix this by retrying with less vectors and finally disabling msi on such failures and falling back on regular interrupts. Reported-by: Amit Shah

On (Tue) Jul 21 2009 [19:54:00], Michael S. Tsirkin wrote: > On Fri, Jul 17, 2009 at 06:34:40PM +0530, Amit Shah wrote: > > Hello, > > > > Using recent qemu-kvm userspace with a slightly older kernel module I > > get this when using the virtio-net device: I was getting this with a very recent kernel in the guest with an older host kernel. 2.6.31-rc3 in the guest and

On (Tue) Jul 21 2009 [19:54:00], Michael S. Tsirkin wrote: > On Fri, Jul 17, 2009 at 06:34:40PM +0530, Amit Shah wrote: > > Hello, > > > > Using recent qemu-kvm userspace with a slightly older kernel module I > > get this when using the virtio-net device: I was getting this with a very recent kernel in the guest with an older host kernel. 2.6.31-rc3 in the guest and

This implements optional MSI-X support in virtio_pci. MSI-X is used whenever the host supports at least 2 MSI-X vectors: 1 for configuration changes and 1 for virtqueues. Per-virtqueue vectors are allocated if enough vectors available. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/virtio/virtio_pci.c | 227 +++++++++++++++++++++++++++++++++++++++----

This implements optional MSI-X support in virtio_pci. MSI-X is used whenever the host supports at least 2 MSI-X vectors: 1 for configuration changes and 1 for virtqueues. Per-virtqueue vectors are allocated if enough vectors available. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/virtio/virtio_pci.c | 227 +++++++++++++++++++++++++++++++++++++++----

This implements optional MSI-X support in virtio_pci. MSI-X is used whenever the host supports at least 2 MSI-X vectors: 1 for configuration changes and 1 for virtqueues. Per-virtqueue vectors are allocated if enough vectors available. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/virtio/virtio_pci.c | 227 +++++++++++++++++++++++++++++++++++++++----

This implements optional MSI-X support in virtio_pci. MSI-X is used whenever the host supports at least 2 MSI-X vectors: 1 for configuration changes and 1 for virtqueues. Per-virtqueue vectors are allocated if enough vectors available. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/virtio/virtio_pci.c | 227 +++++++++++++++++++++++++++++++++++++++----

Michael, Rusty, any comments? On (Thu) 12 Jan 2012 [09:20:06], zanghongyong at huawei.com wrote: > From: Hongyong Zang <zanghongyong at huawei.com> > > changes in vp_try_to_find_vqs: > Virtio-serial's probe() calls it to request irqs and setup vqs of port0 and > controls; add_port() calls it to set up vqs of io_port. > it will not create virtqueue if the name is null.

Michael, Rusty, any comments? On (Thu) 12 Jan 2012 [09:20:06], zanghongyong at huawei.com wrote: > From: Hongyong Zang <zanghongyong at huawei.com> > > changes in vp_try_to_find_vqs: > Virtio-serial's probe() calls it to request irqs and setup vqs of port0 and > controls; add_port() calls it to set up vqs of io_port. > it will not create virtqueue if the name is null.

We don't need to go from vq to vq info on data path, so using direct vq->priv pointer for that seems like a waste. Let's build an array of vq infos, then we can use vq->index for that lookup. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/virtio/virtio_pci.c | 56 +++++++++++++++++++++++++-------------------- 1 file changed, 31 insertions(+), 25

We don't need to go from vq to vq info on data path, so using direct vq->priv pointer for that seems like a waste. Let's build an array of vq infos, then we can use vq->index for that lookup. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/virtio/virtio_pci.c | 56 +++++++++++++++++++++++++-------------------- 1 file changed, 31 insertions(+), 25

msix_user_vectors counted both per-vq and shared/config vectors. This causes BUG_ON when device is removed, as free_vectors tries to free per-vq vectors. Count per-vq vectors separately so they are only freed by del_vq. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/virtio/virtio_pci.c | 38 +++++++++++++++++++++++--------------- 1 files changed, 23 insertions(+), 15

msix_user_vectors counted both per-vq and shared/config vectors. This causes BUG_ON when device is removed, as free_vectors tries to free per-vq vectors. Count per-vq vectors separately so they are only freed by del_vq. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/virtio/virtio_pci.c | 38 +++++++++++++++++++++++--------------- 1 files changed, 23 insertions(+), 15

This lets IRQ layer handle dispatching IRQs to separate handlers for the case where we don't have per-VQ MSI-X vectors, and allows us to greatly simplify the code based on the assumption that we always have interrupt vector 0 (legacy INTx or config interrupt for MSI-X) available, and any other interrupt is request/freed throught the VQ, even if the actual interrupt line might be shared in some

This lets IRQ layer handle dispatching IRQs to separate handlers for the case where we don't have per-VQ MSI-X vectors, and allows us to greatly simplify the code based on the assumption that we always have interrupt vector 0 (legacy INTx or config interrupt for MSI-X) available, and any other interrupt is request/freed throught the VQ, even if the actual interrupt line might be shared in some