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

[Duan, Zhenzhong]

>-----Original Message-----
>From: Cédric Le Goater <clg@redhat.com>
>Subject: Re: [PATCH rfcv1 2/6] hw/pci: introduce
>pci_device_set/unset_iommu_device()
>
>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)
>>   {
>>       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 &&
>
>Why do we test iommu_bus in pci_device_un/set_iommu_device routines
>and
>not in pci_device_iommu_address_space() ?

iommu_bus check in pci_device_iommu_address_space() is dropped in
below commit, I didn't find related discussion in mail history, maybe
by accident? I can add it back if it's not intentional.

ba7d12eb8c  hw/pci: modify pci_setup_iommu() to set PCIIOMMUOps

Thanks
Zhenzhong