On Thu, Aug 01, 2019 at 03:49:37PM +0200, Auger Eric wrote: > Hi Michael, > > On 8/1/19 3:06 PM, Michael S. Tsirkin wrote: > > On Thu, Aug 01, 2019 at 02:15:03PM +0200, Auger Eric wrote: > >> Hi Michael, > >> > >> On 7/30/19 9:35 PM, Michael S. Tsirkin wrote: > >>> On Tue, Jul 30, 2019 at 07:21:36PM +0200, Eric Auger wrote: > >>>> This patch adds virtio-iommu-pci, which is the pci proxy for > >>>> the virtio-iommu device. > >>>> > >>>> Signed-off-by: Eric Auger <eric.au...@redhat.com> > >>> > >>> This part I'm not sure we should merge just yet. The reason being I > >>> think we should limit it to mmio where DT can be used to describe iommu > >>> topology. For PCI I don't see why we shouldn't always expose this > >>> in the config space, and I think it's preferable not to > >>> need to support a mix of DT,ACPI and PCI as options. > >> > >> For context, some discussion related to this topic already arose on v7 > >> revision of the driver: > >> > >> [1] Re: [PATCH v7 0/7] Add virtio-iommu driver > >> https://lore.kernel.org/linux-pci/87a7ioby9u.fsf@morokweng.localdomain/ > >> > >> Some additional thoughts. > >> > >> First considering DT boot. > >> > >> THE DT description features an iommu-map property in the > >> pci-host-ecam-generic node that describes which RIDs are handled by the > >> virtio-iommu and a possible offset/mask to be applied inbetween the RID > >> and the streamID at the input of the IOMMU > >> (Documentation/devicetree/bindings/pci/pci-iommu.txt) > >> > >> As far as I understand when a DMA capable device is setup, its DMA > >> configuration is built using that call chain: > >> > >> pci_dma_configure > >> |_ of_dma_configure > >> |_ of_iommu_configure > >> |_ of_pci_iommu_init > >> |_ of_map_rid > >> > >> I understand you would like the iommu-map/iommu-map-mask info to be > >> exposed directly into the config space of the device instead of inside > >> the DT or IORT table. Assuming a module is initialized sufficiently > >> early to retrieve this info, we would need the resulting info to be > >> consolidated to allow pci_dma_configure chain to work seemlessly. This > >> sounds a significant impact on above kernel infrastructure. > > > > I don't really know what consolidated means. > > It is pretty common for IOMMUs to expose config through > > PCI registers. This typically happens as a fixup. > I meant: instead of retrieving the info through the of_* code you need > to interoperate with the module to retrieve the same info and detect > when you need to take that path instead of the of one.
The way to do it would be with a quirk, and the quirk would not be part of the virtio module - it can poke at the device using virtio_pci_cfg_cap. > > > > I would write a tiny driver to do exactly that, > > and run it from the fixup. > > > > > >> This comes in addition to the development of the "small module that > >> loads early and pokes at the IOMMU sufficiently to get the data about > >> which devices use the IOMMU out of it using standard virtio config > >> space" evoked in [1] + the definition of the data formats to be put in > >> the very cfg space. > > > > That last part is true but that's exactly why I propose we > > wait on this patch a bit. > > > >> With ACPI I understand we have the same kind of infrastructure: > >> drivers/acpi/arm64/iort.c currently extracts the mapping between RC RIDs > >> and IOMMU streamids > >> > >> pci_dma_configure( > >> |_ acpi_dma_configure > >> |_ iort_iommu_configure > >> |_ iort_pci_iommu_init > >> |_ iort_node_map_id > >> |_ iort_id_map > >> > >> Maybe I fail to see the easy and right way to do the integration at > >> kernel level but I am a bit frightened by the efforts that would be > >> requested to follow your suggestion, whereas the DT infra is ready and > >> fully upstreamed to accept the use case. > > > > Did you take a look at drivers/pci/quirks.c and how these run? > > I think it's just a question of adding DECLARE_PCI_FIXUP_CLASS_EARLY > > and running your hook from there. > I will do and trace the code. > > > > > >> For ACPI I agree AFAIK IORT was primarily defined by ARM, for ARM but we > >> prototyped IORT integration with x86 and it worked for pc machine > >> without major trouble. > >> > >> I sent the kernel and qemu patches prototyping this IORT integration: > >> > >> https://github.com/eauger/linux/tree/virtio-iommu-v0.9-iort-x86 > >> https://github.com/eauger/qemu/tree/v3.1.0-rc3-virtio-iommu-v0.9-x86 > >> > >> There ACPI IORT was built for PC machine and the integration effort at > >> both kernel and QEMU level was low. This work would need to be rebased > >> and depends on kernel ACPI related patches that are not yet upstreamed > >> though. > >> > >> Thanks > >> > >> Eric > > > > In the end it might turn out you are right. But it does us no harm to > > delay this just a bit, and for now limit things to ARM where it's > > already used and where alternatives exist. > So if my understanding is correct, at the moment you would accept a DT > integration using MMIO. Is that correct? Meanwhile we can prototype your > suggestion. > > Thanks > > Eric Right. > > > > > >>> > >>>> --- > >>>> > >>>> v8 -> v9: > >>>> - add the msi-bypass property > >>>> - create virtio-iommu-pci.c > >>>> --- > >>>> hw/virtio/Makefile.objs | 1 + > >>>> hw/virtio/virtio-iommu-pci.c | 88 ++++++++++++++++++++++++++++++++ > >>>> include/hw/pci/pci.h | 1 + > >>>> include/hw/virtio/virtio-iommu.h | 1 + > >>>> qdev-monitor.c | 1 + > >>>> 5 files changed, 92 insertions(+) > >>>> create mode 100644 hw/virtio/virtio-iommu-pci.c > >>>> > >>>> diff --git a/hw/virtio/Makefile.objs b/hw/virtio/Makefile.objs > >>>> index f42e4dd94f..80ca719f1c 100644 > >>>> --- a/hw/virtio/Makefile.objs > >>>> +++ b/hw/virtio/Makefile.objs > >>>> @@ -27,6 +27,7 @@ obj-$(CONFIG_VIRTIO_INPUT_HOST) += > >>>> virtio-input-host-pci.o > >>>> obj-$(CONFIG_VIRTIO_INPUT) += virtio-input-pci.o > >>>> obj-$(CONFIG_VIRTIO_RNG) += virtio-rng-pci.o > >>>> obj-$(CONFIG_VIRTIO_BALLOON) += virtio-balloon-pci.o > >>>> +obj-$(CONFIG_VIRTIO_IOMMU) += virtio-iommu-pci.o > >>>> obj-$(CONFIG_VIRTIO_9P) += virtio-9p-pci.o > >>>> obj-$(CONFIG_VIRTIO_SCSI) += virtio-scsi-pci.o > >>>> obj-$(CONFIG_VIRTIO_BLK) += virtio-blk-pci.o > >>>> diff --git a/hw/virtio/virtio-iommu-pci.c b/hw/virtio/virtio-iommu-pci.c > >>>> new file mode 100644 > >>>> index 0000000000..f9977096bd > >>>> --- /dev/null > >>>> +++ b/hw/virtio/virtio-iommu-pci.c > >>>> @@ -0,0 +1,88 @@ > >>>> +/* > >>>> + * Virtio IOMMU PCI Bindings > >>>> + * > >>>> + * Copyright (c) 2019 Red Hat, Inc. > >>>> + * Written by Eric Auger > >>>> + * > >>>> + * This program is free software; you can redistribute it and/or modify > >>>> + * it under the terms of the GNU General Public License version 2 or > >>>> + * (at your option) any later version. > >>>> + */ > >>>> + > >>>> +#include "qemu/osdep.h" > >>>> + > >>>> +#include "virtio-pci.h" > >>>> +#include "hw/virtio/virtio-iommu.h" > >>>> + > >>>> +typedef struct VirtIOIOMMUPCI VirtIOIOMMUPCI; > >>>> + > >>>> +/* > >>>> + * virtio-iommu-pci: This extends VirtioPCIProxy. > >>>> + * > >>>> + */ > >>>> +#define VIRTIO_IOMMU_PCI(obj) \ > >>>> + OBJECT_CHECK(VirtIOIOMMUPCI, (obj), TYPE_VIRTIO_IOMMU_PCI) > >>>> + > >>>> +struct VirtIOIOMMUPCI { > >>>> + VirtIOPCIProxy parent_obj; > >>>> + VirtIOIOMMU vdev; > >>>> +}; > >>>> + > >>>> +static Property virtio_iommu_pci_properties[] = { > >>>> + DEFINE_PROP_UINT32("class", VirtIOPCIProxy, class_code, 0), > >>>> + DEFINE_PROP_BOOL("msi-bypass", VirtIOIOMMUPCI, vdev.msi_bypass, > >>>> true), > >>>> + DEFINE_PROP_END_OF_LIST(), > >>>> +}; > >>>> + > >>>> +static void virtio_iommu_pci_realize(VirtIOPCIProxy *vpci_dev, Error > >>>> **errp) > >>>> +{ > >>>> + VirtIOIOMMUPCI *dev = VIRTIO_IOMMU_PCI(vpci_dev); > >>>> + DeviceState *vdev = DEVICE(&dev->vdev); > >>>> + > >>>> + qdev_set_parent_bus(vdev, BUS(&vpci_dev->bus)); > >>>> + object_property_set_link(OBJECT(dev), > >>>> + OBJECT(pci_get_bus(&vpci_dev->pci_dev)), > >>>> + "primary-bus", errp); > >>>> + object_property_set_bool(OBJECT(vdev), true, "realized", errp); > >>>> +} > >>>> + > >>>> +static void virtio_iommu_pci_class_init(ObjectClass *klass, void *data) > >>>> +{ > >>>> + DeviceClass *dc = DEVICE_CLASS(klass); > >>>> + VirtioPCIClass *k = VIRTIO_PCI_CLASS(klass); > >>>> + PCIDeviceClass *pcidev_k = PCI_DEVICE_CLASS(klass); > >>>> + k->realize = virtio_iommu_pci_realize; > >>>> + set_bit(DEVICE_CATEGORY_MISC, dc->categories); > >>>> + dc->props = virtio_iommu_pci_properties; > >>>> + pcidev_k->vendor_id = PCI_VENDOR_ID_REDHAT_QUMRANET; > >>>> + pcidev_k->device_id = PCI_DEVICE_ID_VIRTIO_IOMMU; > >>>> + pcidev_k->revision = VIRTIO_PCI_ABI_VERSION; > >>>> + pcidev_k->class_id = PCI_CLASS_OTHERS; > >>>> +} > >>>> + > >>>> +static void virtio_iommu_pci_instance_init(Object *obj) > >>>> +{ > >>>> + VirtIOIOMMUPCI *dev = VIRTIO_IOMMU_PCI(obj); > >>>> + > >>>> + virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev), > >>>> + TYPE_VIRTIO_IOMMU); > >>>> +} > >>>> + > >>>> +static const VirtioPCIDeviceTypeInfo virtio_iommu_pci_info = { > >>>> + .base_name = TYPE_VIRTIO_IOMMU_PCI, > >>>> + .generic_name = "virtio-iommu-pci", > >>>> + .transitional_name = "virtio-iommu-pci-transitional", > >>>> + .non_transitional_name = "virtio-iommu-pci-non-transitional", > >>>> + .instance_size = sizeof(VirtIOIOMMUPCI), > >>>> + .instance_init = virtio_iommu_pci_instance_init, > >>>> + .class_init = virtio_iommu_pci_class_init, > >>>> +}; > >>>> + > >>>> +static void virtio_iommu_pci_register(void) > >>>> +{ > >>>> + virtio_pci_types_register(&virtio_iommu_pci_info); > >>>> +} > >>>> + > >>>> +type_init(virtio_iommu_pci_register) > >>>> + > >>>> + > >>>> diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h > >>>> index aaf1b9f70d..492ea7e68d 100644 > >>>> --- a/include/hw/pci/pci.h > >>>> +++ b/include/hw/pci/pci.h > >>>> @@ -86,6 +86,7 @@ extern bool pci_available; > >>>> #define PCI_DEVICE_ID_VIRTIO_9P 0x1009 > >>>> #define PCI_DEVICE_ID_VIRTIO_VSOCK 0x1012 > >>>> #define PCI_DEVICE_ID_VIRTIO_PMEM 0x1013 > >>>> +#define PCI_DEVICE_ID_VIRTIO_IOMMU 0x1014 > >>>> > >>>> #define PCI_VENDOR_ID_REDHAT 0x1b36 > >>>> #define PCI_DEVICE_ID_REDHAT_BRIDGE 0x0001 > >>>> diff --git a/include/hw/virtio/virtio-iommu.h > >>>> b/include/hw/virtio/virtio-iommu.h > >>>> index 56c8b4e57f..893ac65c0b 100644 > >>>> --- a/include/hw/virtio/virtio-iommu.h > >>>> +++ b/include/hw/virtio/virtio-iommu.h > >>>> @@ -25,6 +25,7 @@ > >>>> #include "hw/pci/pci.h" > >>>> > >>>> #define TYPE_VIRTIO_IOMMU "virtio-iommu-device" > >>>> +#define TYPE_VIRTIO_IOMMU_PCI "virtio-iommu-device-base" > >>>> #define VIRTIO_IOMMU(obj) \ > >>>> OBJECT_CHECK(VirtIOIOMMU, (obj), TYPE_VIRTIO_IOMMU) > >>>> > >>>> diff --git a/qdev-monitor.c b/qdev-monitor.c > >>>> index 58222c2211..74cf090c61 100644 > >>>> --- a/qdev-monitor.c > >>>> +++ b/qdev-monitor.c > >>>> @@ -63,6 +63,7 @@ static const QDevAlias qdev_alias_table[] = { > >>>> { "virtio-input-host-ccw", "virtio-input-host", QEMU_ARCH_S390X }, > >>>> { "virtio-input-host-pci", "virtio-input-host", > >>>> QEMU_ARCH_ALL & ~QEMU_ARCH_S390X }, > >>>> + { "virtio-iommu-pci", "virtio-iommu", QEMU_ARCH_ALL & > >>>> ~QEMU_ARCH_S390X }, > >>>> { "virtio-keyboard-ccw", "virtio-keyboard", QEMU_ARCH_S390X }, > >>>> { "virtio-keyboard-pci", "virtio-keyboard", > >>>> QEMU_ARCH_ALL & ~QEMU_ARCH_S390X }, > >>>> -- > >>>> 2.20.1 > >>> > >
