Re: [PATCH Kernel v22 7/8] vfio iommu: Add migration capability to report supported features

From: Kirti Wankhede <kwankhede@nvidia.com>
To: Cornelia Huck <cohuck@redhat.com>
Cc: <alex.williamson@redhat.com>, <cjia@nvidia.com>,
	<kevin.tian@intel.com>, <ziye.yang@intel.com>,
	<changpeng.liu@intel.com>, <yi.l.liu@intel.com>,
	<mlevitsk@redhat.com>, <eskultet@redhat.com>,
	<dgilbert@redhat.com>, <jonathan.davies@nutanix.com>,
	<eauger@redhat.com>, <aik@ozlabs.ru>, <pasic@linux.ibm.com>,
	<felipe@nutanix.com>, <Zhengxiao.zx@Alibaba-inc.com>,
	<shuangtai.tst@alibaba-inc.com>, <Ken.Xue@amd.com>,
	<zhi.a.wang@intel.com>, <yan.y.zhao@intel.com>,
	<qemu-devel@nongnu.org>, <kvm@vger.kernel.org>
Subject: Re: [PATCH Kernel v22 7/8] vfio iommu: Add migration capability to report supported features
Date: Wed, 20 May 2020 20:53:13 +0530	[thread overview]
Message-ID: <58ec5324-43e5-29cb-73b1-3675444cf89b@nvidia.com> (raw)
In-Reply-To: <20200520124200.0b4f3562.cohuck@redhat.com>

On 5/20/2020 4:12 PM, Cornelia Huck wrote:
> On Mon, 18 May 2020 11:26:36 +0530
> Kirti Wankhede <kwankhede@nvidia.com> wrote:
> 
>> Added migration capability in IOMMU info chain.
>> User application should check IOMMU info chain for migration capability
>> to use dirty page tracking feature provided by kernel module.
>> User application must check page sizes supported and maximum dirty
>> bitmap size returned by this capability structure for ioctls used to get
>> dirty bitmap.
>>
>> Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
>> ---
>>   drivers/vfio/vfio_iommu_type1.c | 23 ++++++++++++++++++++++-
>>   include/uapi/linux/vfio.h       | 22 ++++++++++++++++++++++
>>   2 files changed, 44 insertions(+), 1 deletion(-)
> 
> (...)
> 
>> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
>> index a1dd2150971e..aa8aa9dcf02a 100644
>> --- a/include/uapi/linux/vfio.h
>> +++ b/include/uapi/linux/vfio.h
>> @@ -1013,6 +1013,28 @@ struct vfio_iommu_type1_info_cap_iova_range {
>>   	struct	vfio_iova_range iova_ranges[];
>>   };
>>   
>> +/*
>> + * The migration capability allows to report supported features for migration.
>> + *
>> + * The structures below define version 1 of this capability.
>> + *
>> + * The existence of this capability indicates IOMMU kernel driver supports
> 
> s/indicates/indicates that/
> 
>> + * dirty page tracking.
>> + *
>> + * pgsize_bitmap: Kernel driver returns supported page sizes bitmap for dirty
>> + * page tracking.
> 
> "bitmap of supported page sizes for dirty page tracking" ?
> 
>> + * max_dirty_bitmap_size: Kernel driver returns maximum supported dirty bitmap
>> + * size in bytes to be used by user application for ioctls to get dirty bitmap.
> 
> "maximum supported dirty bitmap size in bytes that can be used by user
> applications when getting the dirty bitmap" ?
> 

Done.

>> + */
>> +#define VFIO_IOMMU_TYPE1_INFO_CAP_MIGRATION  1
>> +
>> +struct vfio_iommu_type1_info_cap_migration {
>> +	struct	vfio_info_cap_header header;
>> +	__u32	flags;
>> +	__u64	pgsize_bitmap;
>> +	__u64	max_dirty_bitmap_size;		/* in bytes */
>> +};
>> +
>>   #define VFIO_IOMMU_GET_INFO _IO(VFIO_TYPE, VFIO_BASE + 12)
>>   
>>   /**
> 
> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
> 

Thanks.

Kirti