Re: [Qemu-devel] [PATCH v3 08/12] hw/pci: introduce pci_device_notify_iommu()
> From: Paolo Bonzini [mailto:pbonz...@redhat.com] > Sent: Tuesday, March 6, 2018 7:22 PM > Subject: Re: [Qemu-devel] [PATCH v3 08/12] hw/pci: introduce > pci_device_notify_iommu() > > On 06/03/2018 12:03, Liu, Yi L wrote: > > On Tue, Mar 06, 2018 at 11:18:43AM +0100, Paolo Bonzini wrote: > >> On 05/03/2018 09:42, Liu, Yi L wrote: > >>>> In general I think it's better to change your names from "assigned_dev" > >>>> to "sva_dev", because the point of the list is to only iterate over > >>>> devices that might be interested in using SVA. > >>> > >>> For "assigned_dev", my purpose is to distinguish "assigned devices" > >>> from emulated devices. Only the SVA usage on "assigned devices" is cared > >>> here. > >>> But it is true only SVA capable device is interested. So I may need > >>> to rename it as "assigned_sva_dev". How about your opinion? > >> > >> What you care about is not whether the device assigned, but rather > >> whether it called or not pci_setup_sva_ops. Currently only VFIO does > >> this, but that's not a requirement. Hence my suggestion of calling > >> it sva_dev. > > > > Yes, only VFIO calls pci_setup_sva_ops so far, but it should not limited to. > > I'll apply in next version. > > For what it's worth, I agree with David's suggestion for naming (so > pci_setup_pasid_ops, pasid_dev, etc.) Thanks, Paolo. I would follow suggestions from you two. Regards, Yi Liu
Re: [Qemu-devel] [PATCH v3 08/12] hw/pci: introduce pci_device_notify_iommu()
On Tue, Mar 06, 2018 at 06:47:27PM +0800, Peter Xu wrote:
> On Tue, Mar 06, 2018 at 11:19:13AM +0100, Paolo Bonzini wrote:
> > On 05/03/2018 11:43, Peter Xu wrote:
> > > On Mon, Mar 05, 2018 at 04:43:09PM +0800, Liu, Yi L wrote:
> > >> On Fri, Mar 02, 2018 at 05:06:56PM +0100, Paolo Bonzini wrote:
> > >>> On 01/03/2018 11:33, Liu, Yi L wrote:
> > +pci_device_notify_iommu(pdev, PCI_NTY_DEV_ADD);
> > +
> > pci_setup_sva_ops(pdev, _pci_sva_ops);
> >
> > return;
> > @@ -3134,6 +3136,7 @@ static void vfio_exitfn(PCIDevice *pdev)
> > {
> > VFIOPCIDevice *vdev = DO_UPCAST(VFIOPCIDevice, pdev, pdev);
> >
> > +pci_device_notify_iommu(pdev, PCI_NTY_DEV_DEL);
> > >>>
> > >>> Please make the names longer: PCI_IOMMU_NOTIFY_DEVICE_ADDED and
> > >>> PCI_IOMMU_NOTIFY_DEVICE_REMOVED. (This is independent of my other
> > >>> remark, about doing this in generic PCI code for all devices that
> > >>> register SVA ops).
> > >>
> > >> Thanks for the suggestion, will appply.
> > >
> > > Isn't the name too generic if it's tailored for VFIO only? Would
> > > something like PCI_IOMMU_NOTIFY_VFIO_ADD be a bit better?
> >
> > I don't think it's for VFIO only. It's just that VFIO is the only
> > caller of pci_setup_sva_ops.
>
> Indeed. E.g., we can have emulated devices that also want to provide
> the SVA ops.
Excatly as Paolo commented. ^_^
Thanks,
Yi Liu
Re: [Qemu-devel] [PATCH v3 08/12] hw/pci: introduce pci_device_notify_iommu()
On 06/03/2018 12:03, Liu, Yi L wrote: > On Tue, Mar 06, 2018 at 11:18:43AM +0100, Paolo Bonzini wrote: >> On 05/03/2018 09:42, Liu, Yi L wrote: In general I think it's better to change your names from "assigned_dev" to "sva_dev", because the point of the list is to only iterate over devices that might be interested in using SVA. >>> >>> For "assigned_dev", my purpose is to distinguish "assigned devices" from >>> emulated devices. Only the SVA usage on "assigned devices" is cared here. >>> But it is true only SVA capable device is interested. So I may need to >>> rename it as "assigned_sva_dev". How about your opinion? >> >> What you care about is not whether the device assigned, but rather >> whether it called or not pci_setup_sva_ops. Currently only VFIO does >> this, but that's not a requirement. Hence my suggestion of calling it >> sva_dev. > > Yes, only VFIO calls pci_setup_sva_ops so far, but it should not limited to. > I'll apply in next version. For what it's worth, I agree with David's suggestion for naming (so pci_setup_pasid_ops, pasid_dev, etc.) Paolo
Re: [Qemu-devel] [PATCH v3 08/12] hw/pci: introduce pci_device_notify_iommu()
On Tue, Mar 06, 2018 at 11:18:43AM +0100, Paolo Bonzini wrote: > On 05/03/2018 09:42, Liu, Yi L wrote: > >> In general I think it's better to change your names from "assigned_dev" > >> to "sva_dev", because the point of the list is to only iterate over > >> devices that might be interested in using SVA. > > > > For "assigned_dev", my purpose is to distinguish "assigned devices" from > > emulated devices. Only the SVA usage on "assigned devices" is cared here. > > But it is true only SVA capable device is interested. So I may need to > > rename it as "assigned_sva_dev". How about your opinion? > > What you care about is not whether the device assigned, but rather > whether it called or not pci_setup_sva_ops. Currently only VFIO does > this, but that's not a requirement. Hence my suggestion of calling it > sva_dev. Yes, only VFIO calls pci_setup_sva_ops so far, but it should not limited to. I'll apply in next version. Thanks, Yi Liu
Re: [Qemu-devel] [PATCH v3 08/12] hw/pci: introduce pci_device_notify_iommu()
On Tue, Mar 06, 2018 at 11:19:13AM +0100, Paolo Bonzini wrote:
> On 05/03/2018 11:43, Peter Xu wrote:
> > On Mon, Mar 05, 2018 at 04:43:09PM +0800, Liu, Yi L wrote:
> >> On Fri, Mar 02, 2018 at 05:06:56PM +0100, Paolo Bonzini wrote:
> >>> On 01/03/2018 11:33, Liu, Yi L wrote:
> +pci_device_notify_iommu(pdev, PCI_NTY_DEV_ADD);
> +
> pci_setup_sva_ops(pdev, _pci_sva_ops);
>
> return;
> @@ -3134,6 +3136,7 @@ static void vfio_exitfn(PCIDevice *pdev)
> {
> VFIOPCIDevice *vdev = DO_UPCAST(VFIOPCIDevice, pdev, pdev);
>
> +pci_device_notify_iommu(pdev, PCI_NTY_DEV_DEL);
> >>>
> >>> Please make the names longer: PCI_IOMMU_NOTIFY_DEVICE_ADDED and
> >>> PCI_IOMMU_NOTIFY_DEVICE_REMOVED. (This is independent of my other
> >>> remark, about doing this in generic PCI code for all devices that
> >>> register SVA ops).
> >>
> >> Thanks for the suggestion, will appply.
> >
> > Isn't the name too generic if it's tailored for VFIO only? Would
> > something like PCI_IOMMU_NOTIFY_VFIO_ADD be a bit better?
>
> I don't think it's for VFIO only. It's just that VFIO is the only
> caller of pci_setup_sva_ops.
Indeed. E.g., we can have emulated devices that also want to provide
the SVA ops.
--
Peter Xu
Re: [Qemu-devel] [PATCH v3 08/12] hw/pci: introduce pci_device_notify_iommu()
On 05/03/2018 11:43, Peter Xu wrote:
> On Mon, Mar 05, 2018 at 04:43:09PM +0800, Liu, Yi L wrote:
>> On Fri, Mar 02, 2018 at 05:06:56PM +0100, Paolo Bonzini wrote:
>>> On 01/03/2018 11:33, Liu, Yi L wrote:
+pci_device_notify_iommu(pdev, PCI_NTY_DEV_ADD);
+
pci_setup_sva_ops(pdev, _pci_sva_ops);
return;
@@ -3134,6 +3136,7 @@ static void vfio_exitfn(PCIDevice *pdev)
{
VFIOPCIDevice *vdev = DO_UPCAST(VFIOPCIDevice, pdev, pdev);
+pci_device_notify_iommu(pdev, PCI_NTY_DEV_DEL);
>>>
>>> Please make the names longer: PCI_IOMMU_NOTIFY_DEVICE_ADDED and
>>> PCI_IOMMU_NOTIFY_DEVICE_REMOVED. (This is independent of my other
>>> remark, about doing this in generic PCI code for all devices that
>>> register SVA ops).
>>
>> Thanks for the suggestion, will appply.
>
> Isn't the name too generic if it's tailored for VFIO only? Would
> something like PCI_IOMMU_NOTIFY_VFIO_ADD be a bit better?
I don't think it's for VFIO only. It's just that VFIO is the only
caller of pci_setup_sva_ops.
Paolo
Re: [Qemu-devel] [PATCH v3 08/12] hw/pci: introduce pci_device_notify_iommu()
On 05/03/2018 09:42, Liu, Yi L wrote: >> In general I think it's better to change your names from "assigned_dev" >> to "sva_dev", because the point of the list is to only iterate over >> devices that might be interested in using SVA. > > For "assigned_dev", my purpose is to distinguish "assigned devices" from > emulated devices. Only the SVA usage on "assigned devices" is cared here. > But it is true only SVA capable device is interested. So I may need to > rename it as "assigned_sva_dev". How about your opinion? What you care about is not whether the device assigned, but rather whether it called or not pci_setup_sva_ops. Currently only VFIO does this, but that's not a requirement. Hence my suggestion of calling it sva_dev. Paolo
Re: [Qemu-devel] [PATCH v3 08/12] hw/pci: introduce pci_device_notify_iommu()
On Mon, Mar 05, 2018 at 04:43:09PM +0800, Liu, Yi L wrote:
> On Fri, Mar 02, 2018 at 05:06:56PM +0100, Paolo Bonzini wrote:
> > On 01/03/2018 11:33, Liu, Yi L wrote:
> > > +pci_device_notify_iommu(pdev, PCI_NTY_DEV_ADD);
> > > +
> > > pci_setup_sva_ops(pdev, _pci_sva_ops);
> > >
> > > return;
> > > @@ -3134,6 +3136,7 @@ static void vfio_exitfn(PCIDevice *pdev)
> > > {
> > > VFIOPCIDevice *vdev = DO_UPCAST(VFIOPCIDevice, pdev, pdev);
> > >
> > > +pci_device_notify_iommu(pdev, PCI_NTY_DEV_DEL);
> >
> > Please make the names longer: PCI_IOMMU_NOTIFY_DEVICE_ADDED and
> > PCI_IOMMU_NOTIFY_DEVICE_REMOVED. (This is independent of my other
> > remark, about doing this in generic PCI code for all devices that
> > register SVA ops).
>
> Thanks for the suggestion, will appply.
Isn't the name too generic if it's tailored for VFIO only? Would
something like PCI_IOMMU_NOTIFY_VFIO_ADD be a bit better?
--
Peter Xu
Re: [Qemu-devel] [PATCH v3 08/12] hw/pci: introduce pci_device_notify_iommu()
On Mon, Mar 05, 2018 at 04:27:43PM +0800, Peter Xu wrote:
> On Thu, Mar 01, 2018 at 06:33:31PM +0800, Liu, Yi L wrote:
>
> [...]
>
> > -void pci_setup_iommu(PCIBus *bus, PCIIOMMUFunc fn, void *opaque)
> > +void pci_device_notify_iommu(PCIDevice *dev, PCIDevNotifyType type)
> > {
> > -bus->iommu_fn = fn;
> > +PCIBus *bus = PCI_BUS(pci_get_bus(dev));
> > +PCIBus *iommu_bus = bus;
> > +
> > +while (iommu_bus && !iommu_bus->iommu_fn && iommu_bus->parent_dev) {
> > +iommu_bus = PCI_BUS(pci_get_bus(iommu_bus->parent_dev));
> > +}
> > +if (iommu_bus && iommu_bus->notify_fn) {
> > +iommu_bus->notify_fn(bus,
> > + iommu_bus->iommu_opaque,
> > + dev->devfn,
> > + type);
>
> We didn't really check the return code for notify function. What if
> it failed? If we care, we'd better handle the failure; or we can just
> define the notify_fn() to return void (now it's int).
Good catch. I think we need to handle failure. User should be aware of
it. I'll try to add accordingly in next version.
> > +}
> > +return;
>
> I saw many places in the series that you added explicit return for
> "void" return-typed functions. IMHO all of them can be dropped.
Thanks for spotting it, would fix them in next version.
Regards,
Yi Liu
Re: [Qemu-devel] [PATCH v3 08/12] hw/pci: introduce pci_device_notify_iommu()
On Fri, Mar 02, 2018 at 05:06:56PM +0100, Paolo Bonzini wrote:
> On 01/03/2018 11:33, Liu, Yi L wrote:
> > +pci_device_notify_iommu(pdev, PCI_NTY_DEV_ADD);
> > +
> > pci_setup_sva_ops(pdev, _pci_sva_ops);
> >
> > return;
> > @@ -3134,6 +3136,7 @@ static void vfio_exitfn(PCIDevice *pdev)
> > {
> > VFIOPCIDevice *vdev = DO_UPCAST(VFIOPCIDevice, pdev, pdev);
> >
> > +pci_device_notify_iommu(pdev, PCI_NTY_DEV_DEL);
>
> Please make the names longer: PCI_IOMMU_NOTIFY_DEVICE_ADDED and
> PCI_IOMMU_NOTIFY_DEVICE_REMOVED. (This is independent of my other
> remark, about doing this in generic PCI code for all devices that
> register SVA ops).
Thanks for the suggestion, will appply.
Regards,
Yi Liu
Re: [Qemu-devel] [PATCH v3 08/12] hw/pci: introduce pci_device_notify_iommu()
On Fri, Mar 02, 2018 at 04:12:01PM +0100, Paolo Bonzini wrote: > On 01/03/2018 11:33, Liu, Yi L wrote: > > This patch adds pci_device_notify_iommu() for notify virtual IOMMU > > emulator when assigned device is added. And adds a new notify_func > > in PCIBus. vIOMMU emulator provides the instance of this notify_func. > > > > Reason: > > When virtual IOMMU is exposed to guest, vIOMMU emulator needs to > > programm host IOMMU to setup DMA mapping for assigned devices. This > > is a per-device operation, to be efficient, vIOMMU emulator needs > > to record the assigned devices. > > > > Example: devices assigned thru vfio, vfio_realize would call > > pci_device_notify_iommu() to notify vIOMMU emulator to record necessary > > info for assigned device. > > I think the notification should not be left to the individual device. > Instead, the add notification should be done in pci_setup_sva_ops, and > the delete notification should be done in pci_qdev_unrealize, before > calling pc->exit, and only if dev->sva_ops is not NULL. Agreed. I think it works together with your comments against "[PATCH v3 05/12] hw/pci: introduce PCISVAOps to PCIDevice". Would apply it in next version. > In general I think it's better to change your names from "assigned_dev" > to "sva_dev", because the point of the list is to only iterate over > devices that might be interested in using SVA. For "assigned_dev", my purpose is to distinguish "assigned devices" from emulated devices. Only the SVA usage on "assigned devices" is cared here. But it is true only SVA capable device is interested. So I may need to rename it as "assigned_sva_dev". How about your opinion? Thanks, Yi Liu
Re: [Qemu-devel] [PATCH v3 08/12] hw/pci: introduce pci_device_notify_iommu()
On Thu, Mar 01, 2018 at 06:33:31PM +0800, Liu, Yi L wrote:
[...]
> -void pci_setup_iommu(PCIBus *bus, PCIIOMMUFunc fn, void *opaque)
> +void pci_device_notify_iommu(PCIDevice *dev, PCIDevNotifyType type)
> {
> -bus->iommu_fn = fn;
> +PCIBus *bus = PCI_BUS(pci_get_bus(dev));
> +PCIBus *iommu_bus = bus;
> +
> +while (iommu_bus && !iommu_bus->iommu_fn && iommu_bus->parent_dev) {
> +iommu_bus = PCI_BUS(pci_get_bus(iommu_bus->parent_dev));
> +}
> +if (iommu_bus && iommu_bus->notify_fn) {
> +iommu_bus->notify_fn(bus,
> + iommu_bus->iommu_opaque,
> + dev->devfn,
> + type);
We didn't really check the return code for notify function. What if
it failed? If we care, we'd better handle the failure; or we can just
define the notify_fn() to return void (now it's int).
> +}
> +return;
I saw many places in the series that you added explicit return for
"void" return-typed functions. IMHO all of them can be dropped.
> +}
Thanks,
--
Peter Xu
Re: [Qemu-devel] [PATCH v3 08/12] hw/pci: introduce pci_device_notify_iommu()
On 01/03/2018 11:33, Liu, Yi L wrote:
> +pci_device_notify_iommu(pdev, PCI_NTY_DEV_ADD);
> +
> pci_setup_sva_ops(pdev, _pci_sva_ops);
>
> return;
> @@ -3134,6 +3136,7 @@ static void vfio_exitfn(PCIDevice *pdev)
> {
> VFIOPCIDevice *vdev = DO_UPCAST(VFIOPCIDevice, pdev, pdev);
>
> +pci_device_notify_iommu(pdev, PCI_NTY_DEV_DEL);
Please make the names longer: PCI_IOMMU_NOTIFY_DEVICE_ADDED and
PCI_IOMMU_NOTIFY_DEVICE_REMOVED. (This is independent of my other
remark, about doing this in generic PCI code for all devices that
register SVA ops).
Thanks,
Paolo
Re: [Qemu-devel] [PATCH v3 08/12] hw/pci: introduce pci_device_notify_iommu()
On 01/03/2018 11:33, Liu, Yi L wrote: > This patch adds pci_device_notify_iommu() for notify virtual IOMMU > emulator when assigned device is added. And adds a new notify_func > in PCIBus. vIOMMU emulator provides the instance of this notify_func. > > Reason: > When virtual IOMMU is exposed to guest, vIOMMU emulator needs to > programm host IOMMU to setup DMA mapping for assigned devices. This > is a per-device operation, to be efficient, vIOMMU emulator needs > to record the assigned devices. > > Example: devices assigned thru vfio, vfio_realize would call > pci_device_notify_iommu() to notify vIOMMU emulator to record necessary > info for assigned device. I think the notification should not be left to the individual device. Instead, the add notification should be done in pci_setup_sva_ops, and the delete notification should be done in pci_qdev_unrealize, before calling pc->exit, and only if dev->sva_ops is not NULL. In general I think it's better to change your names from "assigned_dev" to "sva_dev", because the point of the list is to only iterate over devices that might be interested in using SVA. Paolo
