Re: [PATCH v10 Kernel 2/5] vfio iommu: Adds flag to indicate dirty pages tracking capability support

From: Alex Williamson <alex.williamson@redhat.com>
To: Kirti Wankhede <kwankhede@nvidia.com>
Cc: <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>, <cohuck@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 v10 Kernel 2/5] vfio iommu: Adds flag to indicate dirty pages tracking capability support
Date: Mon, 16 Dec 2019 16:16:52 -0700	[thread overview]
Message-ID: <20191216161652.30681b05@x1.home> (raw)
In-Reply-To: <1576527700-21805-3-git-send-email-kwankhede@nvidia.com>

On Tue, 17 Dec 2019 01:51:37 +0530
Kirti Wankhede <kwankhede@nvidia.com> wrote:

> Flag VFIO_IOMMU_INFO_DIRTY_PGS in VFIO_IOMMU_GET_INFO indicates that driver
> support dirty pages tracking.
> 
> Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
> Reviewed-by: Neo Jia <cjia@nvidia.com>
> ---
>  drivers/vfio/vfio_iommu_type1.c | 3 ++-
>  include/uapi/linux/vfio.h       | 5 +++--
>  2 files changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 2ada8e6cdb88..3f6b04f2334f 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -2234,7 +2234,8 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
>  			info.cap_offset = 0; /* output, no-recopy necessary */
>  		}
>  
> -		info.flags = VFIO_IOMMU_INFO_PGSIZES;
> +		info.flags = VFIO_IOMMU_INFO_PGSIZES |
> +			     VFIO_IOMMU_INFO_DIRTY_PGS;

Type1 shouldn't advertise it until it's supported though, right?
Thanks,

Alex

>  
>  		info.iova_pgsizes = vfio_pgsize_bitmap(iommu);
>  
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index a0817ba267c1..81847ed54eb7 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -900,8 +900,9 @@ struct vfio_device_ioeventfd {
>  struct vfio_iommu_type1_info {
>  	__u32	argsz;
>  	__u32	flags;
> -#define VFIO_IOMMU_INFO_PGSIZES (1 << 0)	/* supported page sizes info */
> -#define VFIO_IOMMU_INFO_CAPS	(1 << 1)	/* Info supports caps */
> +#define VFIO_IOMMU_INFO_PGSIZES   (1 << 0) /* supported page sizes info */
> +#define VFIO_IOMMU_INFO_CAPS      (1 << 1) /* Info supports caps */
> +#define VFIO_IOMMU_INFO_DIRTY_PGS (1 << 2) /* supports dirty page tracking */
>  	__u64	iova_pgsizes;	/* Bitmap of supported page sizes */
>  	__u32   cap_offset;	/* Offset within info struct of first cap */
>  };