>-----Original Message-----
>From: Cédric Le Goater <c...@redhat.com>
>Subject: Re: [PATCH rfcv1 2/6] hw/pci: introduce
>pci_device_set/unset_iommu_device()
>
>On 1/23/24 07:37, Duan, Zhenzhong wrote:
>>
>>
>>> -----Original Message-----
>>> From: Cédric Le Goater <c...@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....@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....@intel.com>
>>>> Signed-off-by: Yi Sun <yi.y....@linux.intel.com>
>>>> Signed-off-by: Nicolin Chen <nicol...@nvidia.com>
>>>> Signed-off-by: Zhenzhong Duan <zhenzhong.d...@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.
>
>Can iommu_bus be NULL or should we add an assert ?
I dig into the history changes of pci_device_iommu_address_space() and
below commit added iommu_bus check.
5af2ae230514 pci: Fix pci_device_iommu_address_space() bus propagation
In theory, !iommu_bus->parent_dev take precedency over !iommu_bus,
So we never see iommu_bus NULL, assert may be better.
Thanks
Zhenzhong
