On 5/15/2020 4:29 PM, Cornelia Huck wrote:
On Fri, 15 May 2020 02:07:43 +0530
Kirti Wankhede <kwankhede@xxxxxxxxxx> wrote:
IOMMU container maintains a list of all pages pinned by vfio_pin_pages API.
All pages pinned by vendor driver through this API should be considered as
dirty during migration. When container consists of IOMMU capable device and
all pages are pinned and mapped, then all pages are marked dirty.
Added support to start/stop dirtied pages tracking and to get bitmap of all
dirtied pages for requested IO virtual address range.
Signed-off-by: Kirti Wankhede <kwankhede@xxxxxxxxxx>
Reviewed-by: Neo Jia <cjia@xxxxxxxxxx>
---
include/uapi/linux/vfio.h | 55 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 55 insertions(+)
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index ad9bb5af3463..123de3bc2dce 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -1033,6 +1033,12 @@ struct vfio_iommu_type1_dma_map {
#define VFIO_IOMMU_MAP_DMA _IO(VFIO_TYPE, VFIO_BASE + 13)
+struct vfio_bitmap {
+ __u64 pgsize; /* page size for bitmap in bytes */
+ __u64 size; /* in bytes */
+ __u64 __user *data; /* one bit per page */
+};
+
/**
* VFIO_IOMMU_UNMAP_DMA - _IOWR(VFIO_TYPE, VFIO_BASE + 14,
* struct vfio_dma_unmap)
@@ -1059,6 +1065,55 @@ struct vfio_iommu_type1_dma_unmap {
#define VFIO_IOMMU_ENABLE _IO(VFIO_TYPE, VFIO_BASE + 15)
#define VFIO_IOMMU_DISABLE _IO(VFIO_TYPE, VFIO_BASE + 16)
+/**
+ * VFIO_IOMMU_DIRTY_PAGES - _IOWR(VFIO_TYPE, VFIO_BASE + 17,
+ * struct vfio_iommu_type1_dirty_bitmap)
+ * IOCTL is used for dirty pages tracking.
+ * Caller should set flag depending on which operation to perform, details as
+ * below:
+ *
+ * When IOCTL is called with VFIO_IOMMU_DIRTY_PAGES_FLAG_START set, indicates
+ * migration is active and IOMMU module should track pages which are dirtied or
+ * potentially dirtied by device.
"Calling the IOCTL with VFIO_IOMMU_DIRTY_PAGES_FLAG_START instructs the
IOMMU driver to track pages that are dirtied or potentially dirtied by
the device; designed to be used when a migration is in progress."
?
Ok, updating.
+ * Dirty pages are tracked until tracking is stopped by user application by
+ * setting VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP flag.
"...by calling the IOCTL with VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP." ?
+ *
+ * When IOCTL is called with VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP set, indicates
+ * IOMMU should stop tracking dirtied pages.
"Calling the IOCTL with VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP instructs the
IOMMU driver to stop tracking dirtied pages."
?
Ok.
+ *
+ * When IOCTL is called with VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP flag set,
+ * IOCTL returns dirty pages bitmap for IOMMU container during migration for
+ * given IOVA range.
"Calling the IOCTL with VFIO_IOMMU_DIRTY_PAGES_GET_BITMAP returns the
dirty pages bitmap for the IOMMU container for a given IOVA range." ?
Q: How does this interact with the two other operations? I imagine
getting an empty bitmap before _START
No, if dirty page tracking is not started, get_bitmap IOCTL will fail
with -EINVAL.
and a bitmap-in-progress between
_START and _STOP. > After _STOP, will subsequent calls always give the
same bitmap?
No, return -EINVAL.
User must provide data[] as the structure
+ * vfio_iommu_type1_dirty_bitmap_get through which user provides IOVA range and
+ * pgsize.
"The user must specify the IOVA range and the pgsize through the
vfio_iommu_type1_dirty_bitmap_get structure in the data[] portion."
?
This interface supports to get bitmap of smallest supported pgsize
+ * only and can be modified in future to get bitmap of specified pgsize.
That's a current restriction? How can the user find out whether it has
been lifted (or, more generally, find out which pgsize values are
supported)?
Migration capability is added to IOMMU info chain. That gives supported
pgsize bitmap by IOMMU driver.
+ * User must allocate memory for bitmap, zero the bitmap memory and set size
+ * of allocated memory in bitmap.size field.
"The user must provide a zeroed memory area for the bitmap memory and
specify its size in bitmap.size."
?
One bit is used to represent one
+ * page consecutively starting from iova offset. User should provide page size
+ * in bitmap.pgsize field.
s/User/The user/
Is that the 'pgsize' the comment above talks about?
By specifying pgsize here user can ask for bitmap of specific pgsize.
Bit set in bitmap indicates page at that offset from
+ * iova is dirty.
"A bit set in the bitmap indicates that the page at that offset from
iova is dirty." ?
Caller must set argsz including size of structure
+ * vfio_iommu_type1_dirty_bitmap_get.
s/Caller/The caller/
Does argz also include the size of the bitmap?
No.
+ *
+ * Only one of the flags _START, STOP and _GET may be specified at a time.
s/STOP/_STOP/
(just to be consistent)
+ *
+ */
+struct vfio_iommu_type1_dirty_bitmap {
+ __u32 argsz;
+ __u32 flags;
+#define VFIO_IOMMU_DIRTY_PAGES_FLAG_START (1 << 0)
+#define VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP (1 << 1)
+#define VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP (1 << 2)
+ __u8 data[];
+};
+
+struct vfio_iommu_type1_dirty_bitmap_get {
+ __u64 iova; /* IO virtual address */
+ __u64 size; /* Size of iova range */
+ struct vfio_bitmap bitmap;
+};
That's for type1 only, right?
Yes.
Thanks,
Kirti
+
+#define VFIO_IOMMU_DIRTY_PAGES _IO(VFIO_TYPE, VFIO_BASE + 17)
+
/* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU -------- */
/*
