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 6/8] vfio iommu: Update UNMAP_DMA ioctl to get dirty bitmap before unmap
Date: Wed, 20 May 2020 20:46:39 +0530 [thread overview]
Message-ID: <fedde2aa-5a07-aa17-19ee-c8593b9aa730@nvidia.com> (raw)
In-Reply-To: <20200520122738.351985a3.cohuck@redhat.com>
On 5/20/2020 3:57 PM, Cornelia Huck wrote:
> On Tue, 19 May 2020 12:24:13 +0530
> Kirti Wankhede <kwankhede@nvidia.com> wrote:
>
>> DMA mapped pages, including those pinned by mdev vendor drivers, might
>> get unpinned and unmapped while migration is active and device is still
>> running. For example, in pre-copy phase while guest driver could access
>> those pages, host device or vendor driver can dirty these mapped pages.
>> Such pages should be marked dirty so as to maintain memory consistency
>> for a user making use of dirty page tracking.
>>
>> To get bitmap during unmap, user should allocate memory for bitmap, set
>> it all zeros, set size of allocated memory, set page size to be
>> considered for bitmap and set flag VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP.
>>
>> Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
>> Reviewed-by: Neo Jia <cjia@nvidia.com>
>> ---
>> drivers/vfio/vfio_iommu_type1.c | 62 +++++++++++++++++++++++++++++++++--------
>> include/uapi/linux/vfio.h | 10 +++++++
>> 2 files changed, 61 insertions(+), 11 deletions(-)
>
> (...)
>
>> @@ -1085,6 +1093,7 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
>> ret = -EINVAL;
>> goto unlock;
>> }
>> +
>
> Nit: unrelated whitespace change.
>
>> dma = vfio_find_dma(iommu, unmap->iova + unmap->size - 1, 0);
>> if (dma && dma->iova + dma->size != unmap->iova + unmap->size) {
>> ret = -EINVAL;
>
> (...)
>
>> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
>> index 4850c1fef1f8..a1dd2150971e 100644
>> --- a/include/uapi/linux/vfio.h
>> +++ b/include/uapi/linux/vfio.h
>> @@ -1048,12 +1048,22 @@ struct vfio_bitmap {
>> * field. No guarantee is made to the user that arbitrary unmaps of iova
>> * or size different from those used in the original mapping call will
>> * succeed.
>> + * VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP should be set to get dirty bitmap
>
> s/dirty bitmap/the dirty bitmap/
>
>> + * before unmapping IO virtual addresses. When this flag is set, user must
>
> s/user/the user/
>
>> + * provide data[] as structure vfio_bitmap. User must allocate memory to get
>
> "provide a struct vfio_bitmap in data[]" ?
>
>
>> + * bitmap, zero the bitmap memory and must set size of allocated memory in
>> + * vfio_bitmap.size field.
>
> "The user must provide zero-allocated memory via vfio_bitmap.data and
> its size in the vfio_bitmap.size field." ?
>
>
>> A bit in bitmap represents one page of user provided
>
> s/bitmap/the bitmap/
>
>> + * page size in 'pgsize', consecutively starting from iova offset. Bit set
>
> s/Bit set/A set bit/
>
>> + * indicates page at that offset from iova is dirty. Bitmap of pages in the
>
> s/indicates page/indicates that the page/
>
>> + * range of unmapped size is returned in vfio_bitmap.data
>
> "A bitmap of the pages in the range of the unmapped size is returned in
> the user-provided vfio_bitmap.data." ?
>
>> */
>> struct vfio_iommu_type1_dma_unmap {
>> __u32 argsz;
>> __u32 flags;
>> +#define VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP (1 << 0)
>> __u64 iova; /* IO virtual address */
>> __u64 size; /* Size of mapping (bytes) */
>> + __u8 data[];
>> };
>>
>> #define VFIO_IOMMU_UNMAP_DMA _IO(VFIO_TYPE, VFIO_BASE + 14)
>
> With the nits addressed,
Done.
> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
>
Thanks.
Kirti
next prev parent reply other threads:[~2020-05-20 15:16 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-18 5:56 [PATCH Kernel v22 0/8] Add UAPIs to support migration for VFIO devices Kirti Wankhede
2020-05-18 5:56 ` [PATCH Kernel v22 1/8] vfio: UAPI for migration interface for device state Kirti Wankhede
2020-05-18 5:56 ` [PATCH Kernel v22 2/8] vfio iommu: Remove atomicity of ref_count of pinned pages Kirti Wankhede
2020-05-18 5:56 ` [PATCH Kernel v22 3/8] vfio iommu: Cache pgsize_bitmap in struct vfio_iommu Kirti Wankhede
2020-05-20 10:08 ` Cornelia Huck
2020-05-20 14:46 ` Kirti Wankhede
2020-05-18 5:56 ` [PATCH Kernel v22 4/8] vfio iommu: Add ioctl definition for dirty pages tracking Kirti Wankhede
2020-05-18 5:56 ` [PATCH Kernel v22 5/8] vfio iommu: Implementation of ioctl " Kirti Wankhede
2020-05-18 21:53 ` Alex Williamson
2020-05-19 7:11 ` Kirti Wankhede
2020-05-19 6:52 ` Kirti Wankhede
2020-05-18 5:56 ` [PATCH Kernel v22 6/8] vfio iommu: Update UNMAP_DMA ioctl to get dirty bitmap before unmap Kirti Wankhede
2020-05-19 6:54 ` Kirti Wankhede
2020-05-20 10:27 ` Cornelia Huck
2020-05-20 15:16 ` Kirti Wankhede [this message]
2020-05-18 5:56 ` [PATCH Kernel v22 7/8] vfio iommu: Add migration capability to report supported features Kirti Wankhede
2020-05-20 10:42 ` Cornelia Huck
2020-05-20 15:23 ` Kirti Wankhede
2020-05-18 5:56 ` [PATCH Kernel v22 8/8] vfio: Selective dirty page tracking if IOMMU backed device pins pages Kirti Wankhede
2020-05-19 6:54 ` Kirti Wankhede
2020-05-19 16:58 ` [PATCH Kernel v22 0/8] Add UAPIs to support migration for VFIO devices Alex Williamson
2020-05-20 2:55 ` Yan Zhao
2020-05-20 13:40 ` Kirti Wankhede
2020-05-20 16:46 ` Alex Williamson
2020-05-21 5:08 ` Yan Zhao
2020-05-21 7:09 ` Kirti Wankhede
2020-05-21 7:04 ` Yan Zhao
2020-05-21 7:28 ` Kirti Wankhede
2020-05-21 7:32 ` Kirti Wankhede
2020-05-25 6:59 ` Yan Zhao
2020-05-25 13:20 ` Kirti Wankhede
2020-05-26 20:19 ` Alex Williamson
2020-05-27 6:23 ` Yan Zhao
2020-05-27 8:48 ` Dr. David Alan Gilbert
2020-05-28 8:01 ` Yan Zhao
2020-05-28 22:53 ` Alex Williamson
2020-05-29 11:12 ` Dr. David Alan Gilbert
2020-05-28 22:59 ` Alex Williamson
2020-05-29 4:15 ` Yan Zhao
2020-05-29 17:57 ` Kirti Wankhede
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