Re: [PATCH for-5.0 v11 19/20] pc: Add support for virtio-iommu-pci

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Nov 22, 2019 at 07:29:42PM +0100, Eric Auger wrote:
> The virtio-iommu-pci is instantiated through the -device QEMU
> option. However if instantiated it also requires an IORT ACPI table
> to describe the ID mappings between the root complex and the iommu.
> 
> This patch adds the generation of the IORT table if the
> virtio-iommu-pci device is instantiated.
> 
> We also declare the [0xfee00000 - 0xfeefffff] MSI reserved region
> so that it gets bypassed by the IOMMU.
> 
> Signed-off-by: Eric Auger <eric.auger@redhat.com>

So I'd like us to use virtio config space in preference to ACPI.

Guest bits for that are not ready yet, but I think it's
better to wait than maintaining both ACPI and config space forever
later.

Could you send a smaller patchset without pci/acpi bits for now?

> ---
>  hw/i386/acpi-build.c | 72 ++++++++++++++++++++++++++++++++++++++++++++
>  hw/i386/pc.c         | 15 ++++++++-
>  include/hw/i386/pc.h |  2 ++
>  3 files changed, 88 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index 12ff55fcfb..f09cabdcae 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -2744,6 +2744,72 @@ static bool acpi_get_mcfg(AcpiMcfgInfo *mcfg)
>      return true;
>  }
>  
> +static inline void
> +fill_iort_idmap(AcpiIortIdMapping *idmap, int i,
> +                uint32_t input_base, uint32_t id_count,
> +                uint32_t output_base, uint32_t output_reference)
> +{
> +    idmap[i].input_base = cpu_to_le32(input_base);
> +    idmap[i].id_count = cpu_to_le32(id_count);
> +    idmap[i].output_base = cpu_to_le32(output_base);
> +    idmap[i].output_reference = cpu_to_le32(output_reference);
> +}
> +
> +static void
> +build_iort(GArray *table_data, BIOSLinker *linker, PCMachineState *pcms)
> +{
> +    size_t iommu_node_size, rc_node_size, iommu_node_offset;
> +    int iort_start = table_data->len;
> +    AcpiIortPVIommuPCI *iommu;
> +    AcpiIortIdMapping *idmap;
> +    AcpiIortTable *iort;
> +    size_t iort_length;
> +    AcpiIortRC *rc;
> +
> +    iort = acpi_data_push(table_data, sizeof(*iort));
> +    iort_length = sizeof(*iort);
> +    iort->node_count = cpu_to_le32(2);
> +
> +    /* virtio-iommu node */
> +
> +    iommu_node_offset = sizeof(*iort);
> +    iort->node_offset = cpu_to_le32(iommu_node_offset);
> +    iommu_node_size = sizeof(*iommu);
> +    iort_length += iommu_node_offset;
> +    iommu = acpi_data_push(table_data, iommu_node_size);
> +    iommu->type = ACPI_IORT_NODE_PARAVIRT;
> +    iommu->length = cpu_to_le16(iommu_node_size);
> +    iommu->mapping_count = 0;
> +    iommu->devid = cpu_to_le32(pcms->virtio_iommu_bdf);
> +    iommu->model = cpu_to_le32(ACPI_IORT_NODE_PV_VIRTIO_IOMMU_PCI);
> +
> +    /* Root Complex Node */
> +    rc_node_size = sizeof(*rc) + 2 * sizeof(*idmap);
> +    iort_length += rc_node_size;
> +    rc = acpi_data_push(table_data, rc_node_size);
> +
> +    rc->type = ACPI_IORT_NODE_PCI_ROOT_COMPLEX;
> +    rc->length = cpu_to_le16(rc_node_size);
> +    rc->mapping_count = cpu_to_le32(2);
> +    rc->mapping_offset = cpu_to_le32(sizeof(*rc));
> +
> +    /* fully coherent device */
> +    rc->memory_properties.cache_coherency = cpu_to_le32(1);
> +    rc->memory_properties.memory_flags = 0x3; /* CCA = CPM = DCAS = 1 */
> +    rc->pci_segment_number = 0; /* MCFG pci_segment */
> +    fill_iort_idmap(rc->id_mapping_array, 0, 0, pcms->virtio_iommu_bdf, 0,
> +                    iommu_node_offset);
> +    fill_iort_idmap(rc->id_mapping_array, 1, pcms->virtio_iommu_bdf + 1,
> +                    0xFFFF - pcms->virtio_iommu_bdf,
> +                    pcms->virtio_iommu_bdf + 1, iommu_node_offset);
> +
> +    iort = (AcpiIortTable *)(table_data->data + iort_start);
> +    iort->length = cpu_to_le32(iort_length);
> +
> +    build_header(linker, table_data, (void *)(table_data->data + iort_start),
> +                 "IORT", table_data->len - iort_start, 0, NULL, NULL);
> +}
> +
>  static
>  void acpi_build(AcpiBuildTables *tables, MachineState *machine)
>  {
> @@ -2835,6 +2901,12 @@ void acpi_build(AcpiBuildTables *tables, MachineState *machine)
>              build_slit(tables_blob, tables->linker, machine);
>          }
>      }
> +
> +    if (pcms->virtio_iommu) {
> +        acpi_add_table(table_offsets, tables_blob);
> +        build_iort(tables_blob, tables->linker, pcms);
> +    }
> +
>      if (acpi_get_mcfg(&mcfg)) {
>          acpi_add_table(table_offsets, tables_blob);
>          build_mcfg(tables_blob, tables->linker, &mcfg);
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index ac08e63604..af984ee041 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -84,6 +84,7 @@
>  #include "hw/net/ne2000-isa.h"
>  #include "standard-headers/asm-x86/bootparam.h"
>  #include "hw/virtio/virtio-pmem-pci.h"
> +#include "hw/virtio/virtio-iommu.h"
>  #include "hw/mem/memory-device.h"
>  #include "sysemu/replay.h"
>  #include "qapi/qmp/qerror.h"
> @@ -1940,6 +1941,11 @@ static void pc_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
>          pc_cpu_pre_plug(hotplug_dev, dev, errp);
>      } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_PMEM_PCI)) {
>          pc_virtio_pmem_pci_pre_plug(hotplug_dev, dev, errp);
> +    } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_IOMMU_PCI)) {
> +        /* we declare a VIRTIO_IOMMU_RESV_MEM_T_MSI region */
> +        qdev_prop_set_uint32(dev, "len-reserved-regions", 1);
> +        qdev_prop_set_string(dev, "reserved-regions[0]",
> +                             "0xfee00000, 0xfeefffff, 1");
>      }
>  }
>  
> @@ -1952,6 +1958,12 @@ static void pc_machine_device_plug_cb(HotplugHandler *hotplug_dev,
>          pc_cpu_plug(hotplug_dev, dev, errp);
>      } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_PMEM_PCI)) {
>          pc_virtio_pmem_pci_plug(hotplug_dev, dev, errp);
> +    } else if (object_dynamic_cast(OBJECT(dev), "virtio-iommu-pci")) {
> +        PCMachineState *pcms = PC_MACHINE(hotplug_dev);
> +        PCIDevice *pdev = PCI_DEVICE(dev);
> +
> +        pcms->virtio_iommu = true;
> +        pcms->virtio_iommu_bdf = pci_get_bdf(pdev);
>      }
>  }
>  
> @@ -1990,7 +2002,8 @@ static HotplugHandler *pc_get_hotplug_handler(MachineState *machine,
>  {
>      if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM) ||
>          object_dynamic_cast(OBJECT(dev), TYPE_CPU) ||
> -        object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_PMEM_PCI)) {
> +        object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_PMEM_PCI) ||
> +        object_dynamic_cast(OBJECT(dev), "virtio-iommu-pci")) {
>          return HOTPLUG_HANDLER(machine);
>      }
>  
> diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> index 1f86eba3f9..221b4c6ef9 100644
> --- a/include/hw/i386/pc.h
> +++ b/include/hw/i386/pc.h
> @@ -49,6 +49,8 @@ struct PCMachineState {
>      bool smbus_enabled;
>      bool sata_enabled;
>      bool pit_enabled;
> +    bool virtio_iommu;
> +    uint16_t virtio_iommu_bdf;
>  
>      /* NUMA information: */
>      uint64_t numa_nodes;
> -- 
> 2.20.1