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Re: [Qemu-devel] [PATCH v2 3/6] virtio: support adding sub-regions for n
From: |
Tiwei Bie |
Subject: |
Re: [Qemu-devel] [PATCH v2 3/6] virtio: support adding sub-regions for notify region |
Date: |
Tue, 27 Mar 2018 21:47:05 +0800 |
User-agent: |
NeoMutt/20170113 (1.7.2) |
On Thu, Mar 22, 2018 at 04:57:23PM +0200, Michael S. Tsirkin wrote:
> On Mon, Mar 19, 2018 at 03:15:34PM +0800, Tiwei Bie wrote:
[...]
> > +
> > +bool virtio_pci_page_per_vq_enabled(VirtIODevice *vdev)
> > +{
> > + VirtIOPCIProxy *proxy = virtio_device_to_virtio_pci_proxy(vdev);
> > +
> > + if (proxy == NULL) {
> > + return false;
> > + }
> > +
> > + return !!(proxy->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ);
> > +}
> > +
>
> VIRTIO_PCI_FLAG_PAGE_PER_VQ is not something external users
> should care about. Need to find some other way to express the
> specific requirements.
>
> In particular do you want to use a host page per VQ?
>
> This isn't what VIRTIO_PCI_FLAG_PAGE_PER_VQ does - it uses a 4K offset
> which does not match a memory page size on all platforms.
Yeah, right. I'll think about how to deal with this.
>
>
> > +int virtio_pci_notify_region_map(VirtIODevice *vdev, int queue_idx,
> > + MemoryRegion *mr)
> > +{
> > + VirtIOPCIProxy *proxy = virtio_device_to_virtio_pci_proxy(vdev);
> > + int offset;
> > +
> > + if (proxy == NULL || !virtio_pci_modern(proxy)) {
> > + return -1;
> > + }
> > +
> > + offset = virtio_pci_queue_mem_mult(proxy) * queue_idx;
> > + memory_region_add_subregion(&proxy->notify.mr, offset, mr);
> > +
> > + return 0;
> > +}
> > +
> > +void virtio_pci_notify_region_unmap(VirtIODevice *vdev, MemoryRegion *mr)
> > +{
> > + VirtIOPCIProxy *proxy = virtio_device_to_virtio_pci_proxy(vdev);
> > +
> > + if (proxy != NULL) {
> > + memory_region_del_subregion(&proxy->notify.mr, mr);
> > + }
> > +}
> > +
> > static void virtio_pci_pre_plugged(DeviceState *d, Error **errp)
> > {
> > VirtIOPCIProxy *proxy = VIRTIO_PCI(d);
> > diff --git a/hw/virtio/virtio-pci.h b/hw/virtio/virtio-pci.h
> > index 813082b0d7..8061133741 100644
> > --- a/hw/virtio/virtio-pci.h
> > +++ b/hw/virtio/virtio-pci.h
> > @@ -213,6 +213,11 @@ static inline void
> > virtio_pci_disable_modern(VirtIOPCIProxy *proxy)
> > proxy->disable_modern = true;
> > }
> >
> > +bool virtio_pci_page_per_vq_enabled(VirtIODevice *vdev);
> > +int virtio_pci_notify_region_map(VirtIODevice *vdev, int queue_idx,
> > + MemoryRegion *mr);
> > +void virtio_pci_notify_region_unmap(VirtIODevice *vdev, MemoryRegion *mr);
> > +
> > /*
> > * virtio-scsi-pci: This extends VirtioPCIProxy.
> > */
>
> These are not great APIs unfortunately. Need to come up with generic names.
> E.g. do we register and de-register host notifiers maybe?
>
I like the name "host notifier". I'll try to use it. Thanks a lot!
>
> > diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> > index 006d3d1148..90ee72984c 100644
> > --- a/hw/virtio/virtio.c
> > +++ b/hw/virtio/virtio.c
> > @@ -22,6 +22,7 @@
> > #include "qemu/atomic.h"
> > #include "hw/virtio/virtio-bus.h"
> > #include "hw/virtio/virtio-access.h"
> > +#include "hw/virtio/virtio-pci.h"
> > #include "sysemu/dma.h"
> >
> > /*
> > @@ -2681,6 +2682,44 @@ void virtio_device_release_ioeventfd(VirtIODevice
> > *vdev)
> > virtio_bus_release_ioeventfd(vbus);
> > }
> >
> > +bool virtio_device_parent_is_pci_device(VirtIODevice *vdev)
> > +{
> > + BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
> > + const char *typename = object_get_typename(OBJECT(qbus->parent));
> > +
> > + return strstr(typename, "pci") != NULL;
> > +}
> > +
> > +bool virtio_device_page_per_vq_enabled(VirtIODevice *vdev)
> > +{
> > +#ifdef CONFIG_VIRTIO_PCI
> > + if (virtio_device_parent_is_pci_device(vdev)) {
> > + return virtio_pci_page_per_vq_enabled(vdev);
> > + }
> > +#endif
> > + return false;
> > +}
> > +
>
> A better way to do this is to pass a callback to the bus where each bus can
> implement its own.
>
It's pretty neat! It helped me get rid of all the
changes to the build scripts. Thanks a lot!
Best regards,
Tiwei Bie
- [Qemu-devel] [PATCH v2 0/6] Extend vhost-user to support VFIO based accelerators, Tiwei Bie, 2018/03/19
- [Qemu-devel] [PATCH v2 2/6] vhost-user: introduce shared vhost-user state, Tiwei Bie, 2018/03/19
- [Qemu-devel] [PATCH v2 1/6] vhost-user: support receiving file descriptors in slave_read, Tiwei Bie, 2018/03/19
- [Qemu-devel] [PATCH v2 3/6] virtio: support adding sub-regions for notify region, Tiwei Bie, 2018/03/19
- [Qemu-devel] [PATCH v2 4/6] vfio: support getting VFIOGroup from groupfd, Tiwei Bie, 2018/03/19
- [Qemu-devel] [PATCH v2 5/6] vfio: remove DPRINTF() definition from vfio-common.h, Tiwei Bie, 2018/03/19
- [Qemu-devel] [PATCH v2 6/6] vhost-user: add VFIO based accelerators support, Tiwei Bie, 2018/03/19
- Re: [Qemu-devel] [PATCH v2 0/6] Extend vhost-user to support VFIO based accelerators, Michael S. Tsirkin, 2018/03/22