Re: [PATCH rfcv1 2/6] hw/pci: introduce pci_device_set/unset_iommu_device()

[Eric Auger]

Hi Zhenzhong,

On 1/15/24 11:13, Zhenzhong Duan wrote:
> From: Yi Liu <yi.l.liu@intel.com>
>
> This adds pci_device_set/unset_iommu_device() to set/unset
> IOMMUFDDevice for a given PCIe device. Caller of set
> should fail if set operation fails.
>
> Extract out pci_device_get_iommu_bus_devfn() to facilitate
> implementation of pci_device_set/unset_iommu_device().
>
> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com>
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> ---
>  include/hw/pci/pci.h | 39 ++++++++++++++++++++++++++++++++++-
>  hw/pci/pci.c         | 49 +++++++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 86 insertions(+), 2 deletions(-)
>
> diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
> index fa6313aabc..a810c0ec74 100644
> --- a/include/hw/pci/pci.h
> +++ b/include/hw/pci/pci.h
> @@ -7,6 +7,8 @@
>  /* PCI includes legacy ISA access.  */
>  #include "hw/isa/isa.h"
>  
> +#include "sysemu/iommufd_device.h"
> +
>  extern bool pci_available;
>  
>  /* PCI bus */
> @@ -384,10 +386,45 @@ typedef struct PCIIOMMUOps {
>       *
>       * @devfn: device and function number
>       */
> -   AddressSpace * (*get_address_space)(PCIBus *bus, void *opaque, int devfn);
> +    AddressSpace * (*get_address_space)(PCIBus *bus, void *opaque, int 
> devfn);
> +    /**
> +     * @set_iommu_device: set iommufd device for a PCI device to vIOMMU
> +     *
> +     * Optional callback, if not implemented in vIOMMU, then vIOMMU can't
> +     * utilize iommufd specific features.
> +     *
> +     * Return true if iommufd device is accepted, or else return false with
> +     * errp set.
> +     *
> +     * @bus: the #PCIBus of the PCI device.
> +     *
> +     * @opaque: the data passed to pci_setup_iommu().
> +     *
> +     * @devfn: device and function number of the PCI device.
> +     *
> +     * @idev: the data structure representing iommufd device.
> +     *
> +     */
> +    int (*set_iommu_device)(PCIBus *bus, void *opaque, int32_t devfn,
> +                            IOMMUFDDevice *idev, Error **errp);
> +    /**
> +     * @unset_iommu_device: unset iommufd device for a PCI device from vIOMMU
> +     *
> +     * Optional callback.
> +     *
> +     * @bus: the #PCIBus of the PCI device.
> +     *
> +     * @opaque: the data passed to pci_setup_iommu().
> +     *
> +     * @devfn: device and function number of the PCI device.
> +     */
> +    void (*unset_iommu_device)(PCIBus *bus, void *opaque, int32_t devfn);
>  } PCIIOMMUOps;
>  
>  AddressSpace *pci_device_iommu_address_space(PCIDevice *dev);
> +int pci_device_set_iommu_device(PCIDevice *dev, IOMMUFDDevice *idev,
> +                                Error **errp);
> +void pci_device_unset_iommu_device(PCIDevice *dev);
>  
>  /**
>   * pci_setup_iommu: Initialize specific IOMMU handlers for a PCIBus
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index 76080af580..3848662f95 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -2672,7 +2672,10 @@ static void pci_device_class_base_init(ObjectClass 
> *klass, void *data)
>      }
>  }
>  
> -AddressSpace *pci_device_iommu_address_space(PCIDevice *dev)
> +static void pci_device_get_iommu_bus_devfn(PCIDevice *dev,
> +                                           PCIBus **aliased_pbus,
> +                                           PCIBus **piommu_bus,
> +                                           uint8_t *aliased_pdevfn)
nit: I would drop the p in aliased_pbus andaliased_pdevfn. Maybe you
should allow the caller to pass NUL for aliased_pbus and aliased_pdevfn
as it is the case for pci_device_set_iommu_device() I may resue that
helper in [RFC 2/7] hw/pci: Introduce pci_device_iommu_bus
>  {
>      PCIBus *bus = pci_get_bus(dev);
>      PCIBus *iommu_bus = bus;
> @@ -2717,6 +2720,18 @@ AddressSpace *pci_device_iommu_address_space(PCIDevice 
> *dev)
>  
>          iommu_bus = parent_bus;
>      }
> +    *aliased_pbus = bus;
> +    *piommu_bus = iommu_bus;
> +    *aliased_pdevfn = devfn;
> +}
> +
> +AddressSpace *pci_device_iommu_address_space(PCIDevice *dev)
> +{
> +    PCIBus *bus;
> +    PCIBus *iommu_bus;
> +    uint8_t devfn;
> +
> +    pci_device_get_iommu_bus_devfn(dev, &bus, &iommu_bus, &devfn);
>      if (!pci_bus_bypass_iommu(bus) && iommu_bus->iommu_ops) {
>          return iommu_bus->iommu_ops->get_address_space(bus,
>                                   iommu_bus->iommu_opaque, devfn);
> @@ -2724,6 +2739,38 @@ AddressSpace *pci_device_iommu_address_space(PCIDevice 
> *dev)
>      return &address_space_memory;
>  }
>  
> +int pci_device_set_iommu_device(PCIDevice *dev, IOMMUFDDevice *idev,
> +                                Error **errp)
> +{
> +    PCIBus *bus;
> +    PCIBus *iommu_bus;
> +    uint8_t devfn;
> +
> +    pci_device_get_iommu_bus_devfn(dev, &bus, &iommu_bus, &devfn);
> +    if (!pci_bus_bypass_iommu(bus) && iommu_bus &&
> +        iommu_bus->iommu_ops && iommu_bus->iommu_ops->set_iommu_device) {
> +        return iommu_bus->iommu_ops->set_iommu_device(pci_get_bus(dev),
> +                                                      
> iommu_bus->iommu_opaque,
> +                                                      dev->devfn, idev, 
> errp);
> +    }
> +    return 0;
> +}
> +
> +void pci_device_unset_iommu_device(PCIDevice *dev)
> +{
> +    PCIBus *bus;
> +    PCIBus *iommu_bus;
> +    uint8_t devfn;
> +
> +    pci_device_get_iommu_bus_devfn(dev, &bus, &iommu_bus, &devfn);
> +    if (!pci_bus_bypass_iommu(bus) && iommu_bus &&
> +        iommu_bus->iommu_ops && iommu_bus->iommu_ops->unset_iommu_device) {
> +        return iommu_bus->iommu_ops->unset_iommu_device(pci_get_bus(dev),
> +                                                        
> iommu_bus->iommu_opaque,
> +                                                        dev->devfn);
> +    }
> +}
> +
>  void pci_setup_iommu(PCIBus *bus, const PCIIOMMUOps *ops, void *opaque)
>  {
>      /*
Thanks

Eric