Re: [PATCH v6 05/19] backends/host_iommu_device: Introduce HostIOMMUDeviceCaps

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

On 6/3/24 08:10, Zhenzhong Duan wrote:
> HostIOMMUDeviceCaps's elements map to the host IOMMU's capabilities.
> Different platform IOMMU can support different elements.
>
> Currently only two elements, type and aw_bits, type hints the host
> platform IOMMU type, i.e., INTEL vtd, ARM smmu, etc; aw_bits hints
> host IOMMU address width.
>
> Introduce .get_cap() handler to check if HOST_IOMMU_DEVICE_CAP_XXX
> is supported.
>
> Suggested-by: Cédric Le Goater <clg@redhat.com>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>

I would either squash this patch into patch 1 or if you prefer ti keep
it seperated, add it just after.

Eric
> ---
>  include/sysemu/host_iommu_device.h | 37 ++++++++++++++++++++++++++++++
>  1 file changed, 37 insertions(+)
>
> diff --git a/include/sysemu/host_iommu_device.h b/include/sysemu/host_iommu_device.h
> index 2b58a94d62..d47d1034b1 100644
> --- a/include/sysemu/host_iommu_device.h
> +++ b/include/sysemu/host_iommu_device.h
> @@ -15,11 +15,25 @@
>  #include "qom/object.h"
>  #include "qapi/error.h"
>  
> +/**
> + * struct HostIOMMUDeviceCaps - Define host IOMMU device capabilities.
> + *
> + * @type: host platform IOMMU type.
> + *
> + * @aw_bits: host IOMMU address width. 0xff if no limitation.
> + */
> +typedef struct HostIOMMUDeviceCaps {
> +    uint32_t type;
> +    uint8_t aw_bits;
> +} HostIOMMUDeviceCaps;
> +
>  #define TYPE_HOST_IOMMU_DEVICE "host-iommu-device"
>  OBJECT_DECLARE_TYPE(HostIOMMUDevice, HostIOMMUDeviceClass, HOST_IOMMU_DEVICE)
>  
>  struct HostIOMMUDevice {
>      Object parent_obj;
> +
> +    HostIOMMUDeviceCaps caps;
>  };
>  
>  /**
> @@ -47,5 +61,28 @@ struct HostIOMMUDeviceClass {
>       * Returns: true on success, false on failure.
>       */
>      bool (*realize)(HostIOMMUDevice *hiod, void *opaque, Error **errp);
> +    /**
> +     * @get_cap: check if a host IOMMU device capability is supported.
> +     *
> +     * Optional callback, if not implemented, hint not supporting query
> +     * of @cap.
> +     *
> +     * @hiod: pointer to a host IOMMU device instance.
> +     *
> +     * @cap: capability to check.
> +     *
> +     * @errp: pass an Error out when fails to query capability.
> +     *
> +     * Returns: <0 on failure, 0 if a @cap is unsupported, or else
> +     * 1 or some positive value for some special @cap,
> +     * i.e., HOST_IOMMU_DEVICE_CAP_AW_BITS.
> +     */
> +    int (*get_cap)(HostIOMMUDevice *hiod, int cap, Error **errp);
>  };
> +
> +/*
> + * Host IOMMU device capability list.
> + */
> +#define HOST_IOMMU_DEVICE_CAP_IOMMU_TYPE    0
> +#define HOST_IOMMU_DEVICE_CAP_AW_BITS       1
>  #endif