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From: "Duan, Zhenzhong" <zhenzhong.duan@intel.com>
To: "Cédric Le Goater" <clg@redhat.com>,
	"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Cc: "alex.williamson@redhat.com" <alex.williamson@redhat.com>,
	"eric.auger@redhat.com" <eric.auger@redhat.com>,
	"mst@redhat.com" <mst@redhat.com>,
	"peterx@redhat.com" <peterx@redhat.com>,
	"jasowang@redhat.com" <jasowang@redhat.com>,
	"jgg@nvidia.com" <jgg@nvidia.com>,
	"nicolinc@nvidia.com" <nicolinc@nvidia.com>,
	"joao.m.martins@oracle.com" <joao.m.martins@oracle.com>,
	"Tian, Kevin" <kevin.tian@intel.com>,
	"Liu, Yi L" <yi.l.liu@intel.com>,
	"Peng, Chao P" <chao.p.peng@intel.com>
Subject: RE: [PATCH v3 11/19] backends/iommufd: Implement HostIOMMUDeviceClass::check_cap() handler
Date: Wed, 1 May 2024 12:34:30 +0000	[thread overview]
Message-ID: <SJ0PR11MB674486E8B903DF6B182936F492192@SJ0PR11MB6744.namprd11.prod.outlook.com> (raw)
In-Reply-To: <47877e84-cf7d-4b51-997a-f61cd208a55c@redhat.com>



>-----Original Message-----
>From: Cédric Le Goater <clg@redhat.com>
>Subject: Re: [PATCH v3 11/19] backends/iommufd: Implement
>HostIOMMUDeviceClass::check_cap() handler
>
>On 4/30/24 12:06, Duan, Zhenzhong wrote:
>>
>>
>>> -----Original Message-----
>>> From: Cédric Le Goater <clg@redhat.com>
>>> Subject: Re: [PATCH v3 11/19] backends/iommufd: Implement
>>> HostIOMMUDeviceClass::check_cap() handler
>>>
>>> On 4/29/24 08:50, Zhenzhong Duan wrote:
>>>> Suggested-by: Cédric Le Goater <clg@redhat.com>
>>>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>>>> ---
>>>>    backends/iommufd.c | 18 ++++++++++++++++++
>>>>    1 file changed, 18 insertions(+)
>>>>
>>>> diff --git a/backends/iommufd.c b/backends/iommufd.c
>>>> index d61209788a..28faec528e 100644
>>>> --- a/backends/iommufd.c
>>>> +++ b/backends/iommufd.c
>>>> @@ -233,6 +233,23 @@ int
>>> iommufd_backend_get_device_info(IOMMUFDBackend *be, uint32_t
>devid,
>>>>        return ret;
>>>>    }
>>>>
>>>> +static int hiod_iommufd_check_cap(HostIOMMUDevice *hiod, int cap,
>>> Error **errp)
>>>> +{
>>>> +    switch (cap) {
>>>> +    case HOST_IOMMU_DEVICE_CAP_IOMMUFD:
>>>> +        return 1;
>>>
>>> I don't understand this value.
>>
>> 1 means this host iommu device is attached to IOMMUFD backend,
>> or else 0 if attached to legacy backend.
>
>Hmm, this looks hacky to me and it is not used anywhere in the patchset.
>Let's reconsider when there is actually a use for it. Until then, please
>drop. My feeling is that a new HostIOMMUDeviceClass handler/attributed
>should be introduced instead.

Got it, will drop it in this series.

Is "return 1" directly the concern on your side? If yes, what about adding a new
element be_type which can be initialized in realize(), like below:

--- a/include/sysemu/host_iommu_device.h
+++ b/include/sysemu/host_iommu_device.h
@@ -28,6 +28,9 @@
  * @fs1gp: first stage(a.k.a, Stage-1) 1GB huge page support.
  */
 typedef struct HostIOMMUDeviceCaps {
+#define HOST_IOMMU_DEVICE_CAP_BACKEND_LEGACY        0
+#define HOST_IOMMU_DEVICE_CAP_BACKEND_IOMMUFD       1
+    uint32_t be_type;
     enum iommu_hw_info_type type;
     uint8_t aw_bits;
     bool nesting;
@@ -91,7 +94,7 @@ struct HostIOMMUDeviceClass {
 /*
  * Host IOMMU device capability list.
  */
-#define HOST_IOMMU_DEVICE_CAP_IOMMUFD       0
+#define HOST_IOMMU_DEVICE_CAP_BACKEND_TYPE  0
 #define HOST_IOMMU_DEVICE_CAP_IOMMU_TYPE    1
 #define HOST_IOMMU_DEVICE_CAP_AW_BITS       2
 #define HOST_IOMMU_DEVICE_CAP_NESTING       3

This looks a bit simpler than adding another handler.
Or you have other concern?

Thanks
Zhenzhong 

>
>
>Thanks,
>
>C.
>
>
>
>> Strictly speaking, HOST_IOMMU_DEVICE_CAP_IOMMUFD is not a
>> hardware capability, I'm trying to put all(sw/hw) in CAPs checking
>> framework just like KVM<->qemu CAPs does.
>>
>> Thanks
>> Zhenzhong
>>
>>>
>>>
>>> Thanks,
>>>
>>> C.
>>>
>>>
>>>> +    default:
>>>> +        return host_iommu_device_check_cap_common(hiod, cap, errp);
>>>> +    }
>>>> +}
>>>> +
>>>> +static void hiod_iommufd_class_init(ObjectClass *oc, void *data)
>>>> +{
>>>> +    HostIOMMUDeviceClass *hioc = HOST_IOMMU_DEVICE_CLASS(oc);
>>>> +
>>>> +    hioc->check_cap = hiod_iommufd_check_cap;
>>>> +};
>>>> +
>>>>    static const TypeInfo types[] = {
>>>>        {
>>>>            .name = TYPE_IOMMUFD_BACKEND,
>>>> @@ -251,6 +268,7 @@ static const TypeInfo types[] = {
>>>>            .parent = TYPE_HOST_IOMMU_DEVICE,
>>>>            .instance_size = sizeof(HostIOMMUDeviceIOMMUFD),
>>>>            .class_size = sizeof(HostIOMMUDeviceIOMMUFDClass),
>>>> +        .class_init = hiod_iommufd_class_init,
>>>>            .abstract = true,
>>>>        }
>>>>    };
>>



  reply	other threads:[~2024-05-01 12:35 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-29  6:50 [PATCH v3 00/19] Add a host IOMMU device abstraction to check with vIOMMU Zhenzhong Duan
2024-04-29  6:50 ` [PATCH v3 01/19] backends: Introduce HostIOMMUDevice abstract Zhenzhong Duan
2024-04-29  6:50 ` [PATCH v3 02/19] vfio/container: Introduce HostIOMMUDeviceLegacyVFIO device Zhenzhong Duan
2024-04-30  7:51   ` Cédric Le Goater
2024-04-30  9:13     ` Duan, Zhenzhong
2024-04-30 12:00       ` Cédric Le Goater
2024-04-29  6:50 ` [PATCH v3 03/19] backends/iommufd: Introduce abstract HostIOMMUDeviceIOMMUFD device Zhenzhong Duan
2024-04-29  6:50 ` [PATCH v3 04/19] vfio/iommufd: Introduce HostIOMMUDeviceIOMMUFDVFIO device Zhenzhong Duan
2024-04-30  7:52   ` Cédric Le Goater
2024-04-30  9:25     ` Duan, Zhenzhong
2024-04-29  6:50 ` [PATCH v3 05/19] backends/host_iommu_device: Introduce HostIOMMUDeviceCaps Zhenzhong Duan
2024-04-30  9:41   ` Cédric Le Goater
2024-04-30  9:55     ` Duan, Zhenzhong
2024-04-30 12:01       ` Cédric Le Goater
2024-05-07  6:11   ` Cédric Le Goater
2024-05-07  6:24     ` Duan, Zhenzhong
2024-04-29  6:50 ` [PATCH v3 06/19] range: Introduce range_get_last_bit() Zhenzhong Duan
2024-04-30  9:41   ` Cédric Le Goater
2024-04-30  9:58     ` Duan, Zhenzhong
2024-05-02 10:30       ` Cédric Le Goater
2024-05-06  6:45         ` Duan, Zhenzhong
2024-04-29  6:50 ` [PATCH v3 07/19] vfio/container: Implement HostIOMMUDeviceClass::realize() handler Zhenzhong Duan
2024-04-30  9:41   ` Cédric Le Goater
2024-04-30  9:59     ` Duan, Zhenzhong
2024-04-29  6:50 ` [PATCH v3 08/19] backends/iommufd: Introduce helper function iommufd_backend_get_device_info() Zhenzhong Duan
2024-04-30  9:41   ` Cédric Le Goater
2024-04-30 10:06     ` Duan, Zhenzhong
2024-04-29  6:50 ` [PATCH v3 09/19] vfio/iommufd: Implement HostIOMMUDeviceClass::realize() handler Zhenzhong Duan
2024-04-29  6:50 ` [PATCH v3 10/19] vfio/container: Implement HostIOMMUDeviceClass::check_cap() handler Zhenzhong Duan
2024-04-29  6:50 ` [PATCH v3 11/19] backends/iommufd: " Zhenzhong Duan
2024-04-30  9:41   ` Cédric Le Goater
2024-04-30 10:06     ` Duan, Zhenzhong
2024-04-30 12:12       ` Cédric Le Goater
2024-05-01 12:34         ` Duan, Zhenzhong [this message]
2024-05-02  8:17           ` Cédric Le Goater
2024-05-06  1:47             ` Duan, Zhenzhong
2024-04-29  6:50 ` [PATCH v3 12/19] vfio: Introduce VFIOIOMMUClass::hiod_typename attribute Zhenzhong Duan
2024-04-29  6:50 ` [PATCH v3 13/19] vfio: Create host IOMMU device instance Zhenzhong Duan
2024-04-30  9:41   ` Cédric Le Goater
2024-04-30 10:16     ` Duan, Zhenzhong
2024-04-30 12:15       ` Cédric Le Goater
2024-04-29  6:50 ` [PATCH v3 14/19] hw/pci: Introduce helper function pci_device_get_iommu_bus_devfn() Zhenzhong Duan
2024-04-29  6:50 ` [PATCH v3 15/19] hw/pci: Introduce pci_device_[set|unset]_iommu_device() Zhenzhong Duan
2024-05-07  7:04   ` Cédric Le Goater
2024-05-07  7:48     ` Duan, Zhenzhong
2024-05-07 12:26       ` Cédric Le Goater
2024-05-08  6:24         ` Duan, Zhenzhong
2024-04-29  6:50 ` [PATCH v3 16/19] vfio/pci: Pass HostIOMMUDevice to vIOMMU Zhenzhong Duan
2024-04-29  6:50 ` [PATCH v3 17/19] intel_iommu: Extract out vtd_cap_init() to initialize cap/ecap Zhenzhong Duan
2024-04-29  6:50 ` [PATCH v3 18/19] intel_iommu: Implement [set|unset]_iommu_device() callbacks Zhenzhong Duan
2024-04-29  6:50 ` [PATCH v3 19/19] intel_iommu: Check compatibility with host IOMMU capabilities Zhenzhong Duan
2024-05-03 14:04 ` [PATCH v3 00/19] Add a host IOMMU device abstraction to check with vIOMMU Cédric Le Goater
2024-05-03 14:10   ` Jason Gunthorpe
2024-05-03 14:29     ` Cédric Le Goater
2024-05-06  2:30   ` Duan, Zhenzhong
2024-05-06 12:05     ` Jason Gunthorpe
2024-05-07  2:24       ` Duan, Zhenzhong
2024-05-07 11:58         ` Jason Gunthorpe
2024-05-08  6:36           ` Duan, Zhenzhong

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