From: Kunkun Jiang <jiangkunkun@xxxxxxxxxx>
In the past if vfio_iommu is not of pinned_page_dirty_scope and
vfio_dma is iommu_mapped, we populate full dirty bitmap for this
vfio_dma. Now we can try to get dirty log from iommu before make
the lousy decision.
The new dirty bitmap population policy:
In detail, if all vfio_group are of pinned_page_dirty_scope, the
dirty bitmap population is not affected. If there are vfio_groups
not of pinned_page_dirty_scope and all domains support HWDBM, we
can try to get dirty log from IOMMU. Otherwise, lead to full dirty
bitmap.
Consider DMA and group hotplug:
Start dirty log for newly added DMA range, and stop dirty log for
DMA range going to remove.
If a domain don't support HWDBM at start, but can support it after
hotplug some groups (attach a first group with HWDBM or detach all
groups without HWDBM). If a domain support HWDBM at start, but do
not support it after hotplug some groups (attach a group without
HWDBM or detach all groups without HWDBM). So our policy is that
switch dirty log for domains dynamically.
Co-developed-by: Keqian Zhu <zhukeqian1@xxxxxxxxxx>
Signed-off-by: Kunkun Jiang <jiangkunkun@xxxxxxxxxx>
---
drivers/vfio/vfio_iommu_type1.c | 180 ++++++++++++++++++++++++++++++--
1 file changed, 172 insertions(+), 8 deletions(-)
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 146aaf95589c..12fe1cf9113e 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -1200,6 +1200,46 @@ static void vfio_update_pgsize_bitmap(struct vfio_iommu *iommu)
}
}
+static int vfio_iommu_dirty_log_clear(struct vfio_iommu *iommu,
+ dma_addr_t start_iova, size_t size,
+ unsigned long *bitmap_buffer,
+ dma_addr_t base_iova,
+ unsigned long pgshift)
+{
+ struct vfio_domain *d;
+ int ret = 0;
+
+ list_for_each_entry(d, &iommu->domain_list, next) {
+ ret = iommu_clear_dirty_log(d->domain, start_iova, size,
+ bitmap_buffer, base_iova, pgshift);
+ if (ret) {
+ pr_warn("vfio_iommu dirty log clear failed!\n");
+ break;
+ }
+ }
+
+ return ret;
+}
+
+static int vfio_iommu_dirty_log_sync(struct vfio_iommu *iommu,
+ struct vfio_dma *dma,
+ unsigned long pgshift)
+{
+ struct vfio_domain *d;
+ int ret = 0;
+
+ list_for_each_entry(d, &iommu->domain_list, next) {
+ ret = iommu_sync_dirty_log(d->domain, dma->iova, dma->size,
+ dma->bitmap, dma->iova, pgshift);
+ if (ret) {
+ pr_warn("vfio_iommu dirty log sync failed!\n");
+ break;
+ }
+ }
+
+ return ret;
+}
+
static int update_user_bitmap(u64 __user *bitmap, struct vfio_iommu *iommu,
struct vfio_dma *dma, dma_addr_t base_iova,
size_t pgsize)
@@ -1210,13 +1250,24 @@ static int update_user_bitmap(u64 __user *bitmap, struct vfio_iommu *iommu,
unsigned long copy_offset = bit_offset / BITS_PER_LONG;
unsigned long shift = bit_offset % BITS_PER_LONG;
unsigned long leftover;
+ bool iommu_hwdbm_dirty = false;
+ int ret;
- /*
- * mark all pages dirty if any IOMMU capable device is not able
- * to report dirty pages and all pages are pinned and mapped.
- */
- if (iommu->num_non_pinned_groups && dma->iommu_mapped)
+ if (!iommu->num_non_pinned_groups || !dma->iommu_mapped) {
+ /* nothing to do */
+ } else if (!iommu->num_non_hwdbm_domains) {
+ /* try to get dirty log from IOMMU */
+ iommu_hwdbm_dirty = true;
+ ret = vfio_iommu_dirty_log_sync(iommu, dma, pgshift);
+ if (ret)
+ return ret;
+ } else {
+ /*
+ * mark all pages dirty if any IOMMU capable device is not able
+ * to report dirty pages and all pages are pinned and mapped.
+ */
bitmap_set(dma->bitmap, 0, nbits);
+ }
if (shift) {
bitmap_shift_left(dma->bitmap, dma->bitmap, shift,
@@ -1234,6 +1285,11 @@ static int update_user_bitmap(u64 __user *bitmap, struct vfio_iommu *iommu,
DIRTY_BITMAP_BYTES(nbits + shift)))
return -EFAULT;
+ /* Recover the bitmap if it'll be used to clear hardware dirty log */
+ if (shift && iommu_hwdbm_dirty)
+ bitmap_shift_right(dma->bitmap, dma->bitmap, shift,
+ nbits + shift);
+
return 0;
}
@@ -1272,6 +1328,16 @@ static int vfio_iova_dirty_bitmap(u64 __user *bitmap, struct vfio_iommu *iommu,
if (ret)
return ret;
+ /* Clear iommu dirty log to re-enable dirty log tracking */
+ if (iommu->num_non_pinned_groups && dma->iommu_mapped &&
+ !iommu->num_non_hwdbm_domains) {
+ ret = vfio_iommu_dirty_log_clear(iommu, dma->iova,
+ dma->size, dma->bitmap, dma->iova,
+ pgshift);
+ if (ret)
+ return ret;
+ }
+
/*
* Re-populate bitmap to include all pinned pages which are
* considered as dirty but exclude pages which are unpinned and
@@ -1292,6 +1358,22 @@ static int verify_bitmap_size(uint64_t npages, uint64_t bitmap_size)
return 0;
}
+static void vfio_dma_dirty_log_switch(struct vfio_iommu *iommu,
+ struct vfio_dma *dma, bool enable)
+{
+ struct vfio_domain *d;
+
+ if (!dma->iommu_mapped)
+ return;
+
+ list_for_each_entry(d, &iommu->domain_list, next) {
+ if (!d->iommu_hwdbm)
+ continue;
+ WARN_ON(iommu_switch_dirty_log(d->domain, enable, dma->iova,
+ dma->size, d->prot | dma->prot));
+ }
+}
+
static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
struct vfio_iommu_type1_dma_unmap *unmap,
struct vfio_bitmap *bitmap)
@@ -1444,6 +1526,10 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
break;
}
+ /* Stop log for removed dma */
+ if (iommu->dirty_page_tracking)
+ vfio_dma_dirty_log_switch(iommu, dma, false);
+
unmapped += dma->size;
n = rb_next(n);
vfio_remove_dma(iommu, dma);
@@ -1675,8 +1761,13 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
if (!ret && iommu->dirty_page_tracking) {
ret = vfio_dma_bitmap_alloc(dma, pgsize);
- if (ret)
+ if (ret) {
vfio_remove_dma(iommu, dma);
+ goto out_unlock;
+ }
+
+ /* Start dirty log for newly added dma */
+ vfio_dma_dirty_log_switch(iommu, dma, true);
}
out_unlock:
@@ -2240,6 +2331,21 @@ static void vfio_iommu_iova_insert_copy(struct vfio_iommu *iommu,
list_splice_tail(iova_copy, iova);
}
+static void vfio_domain_dirty_log_switch(struct vfio_iommu *iommu,
+ struct vfio_domain *d, bool enable)
+{
+ struct rb_node *n;
+ struct vfio_dma *dma;
+
+ for (n = rb_first(&iommu->dma_list); n; n = rb_next(n)) {
+ dma = rb_entry(n, struct vfio_dma, node);
+ if (!dma->iommu_mapped)
+ continue;
+ WARN_ON(iommu_switch_dirty_log(d->domain, enable, dma->iova,
+ dma->size, d->prot | dma->prot));
+ }
+}
+
/*
* Called after a new group is added to the iommu_domain, or an old group is
* removed from the iommu_domain. Update the HWDBM status of vfio_domain and
@@ -2251,13 +2357,48 @@ static void vfio_iommu_update_hwdbm(struct vfio_iommu *iommu,
{
bool old_hwdbm = domain->iommu_hwdbm;
bool new_hwdbm = iommu_support_dirty_log(domain->domain);
+ bool singular = list_is_singular(&domain->group_list);
+ bool num_non_hwdbm_zeroed = false;
+ bool log_enabled, should_enable;
if (old_hwdbm && !new_hwdbm && attach) {
iommu->num_non_hwdbm_domains++;
} else if (!old_hwdbm && new_hwdbm && !attach) {
iommu->num_non_hwdbm_domains--;
+ if (!iommu->num_non_hwdbm_domains)
+ num_non_hwdbm_zeroed = true;
}
domain->iommu_hwdbm = new_hwdbm;
+
+ if (!iommu->dirty_page_tracking)
+ return;
+
+ /*
+ * When switch the dirty policy from full dirty to iommu hwdbm, we must
+ * populate full dirty now to avoid losing dirty.
+ */
+ if (iommu->num_non_pinned_groups && num_non_hwdbm_zeroed)
+ vfio_iommu_populate_bitmap_full(iommu);
+
+ /*
+ * The vfio_domain can switch dirty log tracking dynamically due to
+ * group attach/detach. The basic idea is to convert current dirty log
+ * status to desired dirty log status.
+ *
+ * If old_hwdbm is true then dirty log has been enabled. One exception
+ * is that this is the first group attached to a domain.
+ *
+ * If new_hwdbm is true then dirty log should be enabled. One exception
+ * is that this is the last group detached from a domain.
+ */
+ log_enabled = old_hwdbm && !(attach && singular);
+ should_enable = new_hwdbm && !(!attach && singular);
+
+ /* Switch dirty log tracking when status changed */
+ if (should_enable && !log_enabled)
+ vfio_domain_dirty_log_switch(iommu, domain, true);
+ else if (!should_enable && log_enabled)
+ vfio_domain_dirty_log_switch(iommu, domain, false);
}
static int vfio_iommu_type1_attach_group(void *iommu_data,
@@ -2664,7 +2805,11 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
*/
if (update_dirty_scope) {
iommu->num_non_pinned_groups--;
- if (iommu->dirty_page_tracking)
+ /*
+ * When switch the dirty policy from full dirty to pinned scope,
+ * we must populate full dirty now to avoid losing dirty.
+ */
+ if (iommu->dirty_page_tracking && iommu->num_non_hwdbm_domains)
vfio_iommu_populate_bitmap_full(iommu);
}
mutex_unlock(&iommu->lock);
@@ -3008,6 +3153,22 @@ static int vfio_iommu_type1_unmap_dma(struct vfio_iommu *iommu,
-EFAULT : 0;
}
+static void vfio_iommu_dirty_log_switch(struct vfio_iommu *iommu, bool enable)
+{
+ struct vfio_domain *d;
+
+ /*
+ * We enable dirty log tracking for these vfio_domains that support
+ * HWDBM. Even if all iommu domains don't support HWDBM for now. They
+ * may support it after detach some groups.
+ */
+ list_for_each_entry(d, &iommu->domain_list, next) {
+ if (!d->iommu_hwdbm)
+ continue;
+ vfio_domain_dirty_log_switch(iommu, d, enable);
+ }
+}
+
static int vfio_iommu_type1_dirty_pages(struct vfio_iommu *iommu,
unsigned long arg)
{
@@ -3040,8 +3201,10 @@ static int vfio_iommu_type1_dirty_pages(struct vfio_iommu *iommu,
pgsize = 1 << __ffs(iommu->pgsize_bitmap);
if (!iommu->dirty_page_tracking) {
ret = vfio_dma_bitmap_alloc_all(iommu, pgsize);
- if (!ret)
+ if (!ret) {
iommu->dirty_page_tracking = true;
+ vfio_iommu_dirty_log_switch(iommu, true);
+ }
}
mutex_unlock(&iommu->lock);
return ret;
@@ -3050,6 +3213,7 @@ static int vfio_iommu_type1_dirty_pages(struct vfio_iommu *iommu,
if (iommu->dirty_page_tracking) {
iommu->dirty_page_tracking = false;
vfio_dma_bitmap_free_all(iommu);
+ vfio_iommu_dirty_log_switch(iommu, false);
}
mutex_unlock(&iommu->lock);
return 0;
--
2.19.1
