Re: [PATCH v2 2/8] hw/acpi: Add VIOT table

[Eric Auger <eric.auger@redhat.com>]

Hi Jean,

On 9/3/21 4:32 PM, Jean-Philippe Brucker wrote:
> Add a function that generates a Virtual I/O Translation table (VIOT),
> describing the topology of paravirtual IOMMUs. The table is created when
> instantiating a virtio-iommu device. It contains a virtio-iommu node and
> PCI Range nodes for endpoints managed by the IOMMU. By default, a single
> node describes all PCI devices. When passing the "default_bus_bypass_iommu"
> machine option and "bypass_iommu" PXB option, only buses that do not
> bypass the IOMMU are described by PCI Range nodes.

You may consider to add a test for the new VIOT table (However this may
be added afterwards). See tests/qtest/bios-tables-test.c for the process
and examples.
>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> ---
>  hw/acpi/Kconfig     |   4 ++
>  hw/acpi/viot.h      |  13 +++++
>  hw/acpi/viot.c      | 112 ++++++++++++++++++++++++++++++++++++++++++++
>  hw/acpi/meson.build |   1 +
>  4 files changed, 130 insertions(+)
>  create mode 100644 hw/acpi/viot.h
>  create mode 100644 hw/acpi/viot.c
>
> diff --git a/hw/acpi/Kconfig b/hw/acpi/Kconfig
> index cfc4ede8d9..abad79c103 100644
> --- a/hw/acpi/Kconfig
> +++ b/hw/acpi/Kconfig
> @@ -41,6 +41,10 @@ config ACPI_VMGENID
>      default y
>      depends on PC
>  
> +config ACPI_VIOT
> +    bool
> +    depends on ACPI
> +
>  config ACPI_HW_REDUCED
>      bool
>      select ACPI
> diff --git a/hw/acpi/viot.h b/hw/acpi/viot.h
> new file mode 100644
> index 0000000000..4cef29a640
> --- /dev/null
> +++ b/hw/acpi/viot.h
> @@ -0,0 +1,13 @@
> +/*
> + * ACPI Virtual I/O Translation Table implementation
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +#ifndef VIOT_H
> +#define VIOT_H
> +
> +void build_viot(GArray *table_data, BIOSLinker *linker,
> +                uint16_t virtio_iommu_bdf, const char *oem_id,
> +                const char *oem_table_id);
> +
> +#endif /* VIOT_H */
> diff --git a/hw/acpi/viot.c b/hw/acpi/viot.c
> new file mode 100644
> index 0000000000..81bb2e93ff
> --- /dev/null
> +++ b/hw/acpi/viot.c
> @@ -0,0 +1,112 @@
> +/*
> + * ACPI Virtual I/O Translation table implementation
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +#include "qemu/osdep.h"
> +#include "hw/acpi/acpi.h"
> +#include "hw/acpi/aml-build.h"
> +#include "hw/acpi/viot.h"
> +#include "hw/pci/pci.h"
> +#include "hw/pci/pci_host.h"
> +
> +struct viot_pci_ranges {
> +    GArray *blob;
> +    size_t count;
> +    uint16_t output_node;
> +};
> +
> +/* Build PCI range for a given PCI host bridge */
chapter 1.3
> +static int viot_host_bridges(Object *obj, void *opaque)
> +{
> +    struct viot_pci_ranges *pci_ranges = opaque;
> +    GArray *blob = pci_ranges->blob;
> +
> +    if (object_dynamic_cast(obj, TYPE_PCI_HOST_BRIDGE)) {
> +        PCIBus *bus = PCI_HOST_BRIDGE(obj)->bus;
> +
> +        if (bus && !pci_bus_bypass_iommu(bus)) {
> +            int min_bus, max_bus;
> +
> +            pci_bus_range(bus, &min_bus, &max_bus);
> +
> +            /* Type */
> +            build_append_int_noprefix(blob, ACPI_VIOT_NODE_PCI_RANGE, 1);
s/ACPI_VIOT_NODE_PCI_RANGE/1
> +            /* Reserved */
> +            build_append_int_noprefix(blob, 0, 1);
> +            /* Length */
> +            build_append_int_noprefix(blob, sizeof(AcpiViotPciRange), 2);
hardcode the size
> +            /* Endpoint start */
> +            build_append_int_noprefix(blob, PCI_BUILD_BDF(min_bus, 0), 4);
> +            /* PCI Segment start */
> +            build_append_int_noprefix(blob, 0, 2);
> +            /* PCI Segment end */
> +            build_append_int_noprefix(blob, 0, 2);
> +            /* PCI BDF start */
> +            build_append_int_noprefix(blob, PCI_BUILD_BDF(min_bus, 0), 2);
> +            /* PCI BDF end */
> +            build_append_int_noprefix(blob, PCI_BUILD_BDF(max_bus, 0xff), 2);
> +            /* Output node */
> +            build_append_int_noprefix(blob, pci_ranges->output_node, 2);
> +            /* Reserved */
> +            build_append_int_noprefix(blob, 0, 6);
> +
> +            pci_ranges->count++;
> +        }
> +    }
> +
> +    return 0;
> +}
> +
> +/*
> + * Generate a VIOT table with one PCI-based virtio-iommu that manages PCI
> + * endpoints.
Add a link to the doc + Table refs?

https://jpbrucker.net/virtio-iommu/viot/viot-v9.pdf

> + */
> +void build_viot(GArray *table_data, BIOSLinker *linker,
> +                uint16_t virtio_iommu_bdf, const char *oem_id,
> +                const char *oem_table_id)
> +{
> +    /* virtio-iommu node follows the header */
> +    int viommu_off = sizeof(AcpiViot);
> +    int viot_start = table_data->len;
> +    struct viot_pci_ranges pci_ranges = {
> +        .output_node = viommu_off,
> +        .blob = g_array_new(false, true, 1),
> +    };
> +
> +    /* Build the list of PCI ranges that this viommu manages */
> +    object_child_foreach_recursive(object_get_root(), viot_host_bridges,
> +                                   &pci_ranges);
> +
> +    /* VIOT header */
> +    acpi_data_push(table_data, sizeof(AcpiTableHeader));
Depending on the order of landing, this may be replaced by Igor's

acpi_init_table() and associated with acpi_table_composed().

> +    /* Node count */
> +    build_append_int_noprefix(table_data, pci_ranges.count + 1, 2);
> +    /* Node offset */
> +    build_append_int_noprefix(table_data, viommu_off, 2);
> +    /* Reserved */
> +    build_append_int_noprefix(table_data, 0, 8);
> +
> +    /* Virtio-iommu based on virtio-pci */
chapter 1.1. By the way may be worth adding table titles in the spec.
> +    /* Type */
> +    build_append_int_noprefix(table_data, ACPI_VIOT_NODE_VIRTIO_IOMMU_PCI, 1);
s/ACPI_VIOT_NODE_VIRTIO_IOMMU_PCI/3 or put the defines here instead of
in the header.
> +    /* Reserved */
> +    build_append_int_noprefix(table_data, 0, 1);
> +    /* Length */
> +    build_append_int_noprefix(table_data, sizeof(AcpiViotVirtioIommuPci), 2);
hardcode the size of AcpiViotVirtioIommuPci
> +    /* PCI Segment */
> +    build_append_int_noprefix(table_data, 0, 2);
> +    /* PCI BDF number */
> +    build_append_int_noprefix(table_data, virtio_iommu_bdf, 2);
> +    /* Reserved */
> +    build_append_int_noprefix(table_data, 0, 8);
> +
> +    /* PCI ranges found above */
> +    g_array_append_vals(table_data, pci_ranges.blob->data,
> +                        pci_ranges.blob->len);
> +    g_array_free(pci_ranges.blob, true);
> +
> +    build_header(linker, table_data, (void *)(table_data->data + viot_start),
> +                 "VIOT", table_data->len - viot_start, 0, oem_id, oem_table_id);

acpi_table_composed() or whatever its new name

> +}
> +
> diff --git a/hw/acpi/meson.build b/hw/acpi/meson.build
> index 29f804d13e..a510988b27 100644
> --- a/hw/acpi/meson.build
> +++ b/hw/acpi/meson.build
> @@ -16,6 +16,7 @@ acpi_ss.add(when: 'CONFIG_ACPI_HW_REDUCED', if_true: files('generic_event_device
>  acpi_ss.add(when: 'CONFIG_ACPI_HMAT', if_true: files('hmat.c'))
>  acpi_ss.add(when: 'CONFIG_ACPI_APEI', if_true: files('ghes.c'), if_false: files('ghes-stub.c'))
>  acpi_ss.add(when: 'CONFIG_ACPI_X86', if_true: files('piix4.c', 'pcihp.c'))
> +acpi_ss.add(when: 'CONFIG_ACPI_VIOT', if_true: files('viot.c'))
there is a conflict with main now if I did not mess up things

<<<<<<< HEAD
acpi_ss.add(when: 'CONFIG_ACPI_PIIX4', if_true: files('piix4.c'))
acpi_ss.add(when: 'CONFIG_ACPI_PCIHP', if_true: files('pcihp.c'))
acpi_ss.add(when: 'CONFIG_ACPI_PCIHP', if_false:
files('acpi-pci-hotplug-stub.c'))
=======
acpi_ss.add(when: 'CONFIG_ACPI_X86', if_true: files('piix4.c', 'pcihp.c'))
acpi_ss.add(when: 'CONFIG_ACPI_VIOT', if_true: files('viot.c'))
>>>>>>> hw/acpi: Add VIOT table

Thanks

Eric


>  acpi_ss.add(when: 'CONFIG_ACPI_X86_ICH', if_true: files('ich9.c', 'tco.c'))
>  acpi_ss.add(when: 'CONFIG_IPMI', if_true: files('ipmi.c'), if_false: files('ipmi-stub.c'))
>  acpi_ss.add(when: 'CONFIG_PC', if_false: files('acpi-x86-stub.c'))