[PATCH V1 5/5] vfio: block during VA suspend

[Steve Sistare <steven.sistare@oracle.com>]

Block translation of host virtual address while an iova range is suspended.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
 drivers/vfio/vfio_iommu_type1.c | 48 ++++++++++++++++++++++++++++++++++++++---
 1 file changed, 45 insertions(+), 3 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 2c164a6..8035b9a 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -31,6 +31,8 @@
 #include <linux/rbtree.h>
 #include <linux/sched/signal.h>
 #include <linux/sched/mm.h>
+#include <linux/delay.h>
+#include <linux/kthread.h>
 #include <linux/slab.h>
 #include <linux/uaccess.h>
 #include <linux/vfio.h>
@@ -484,6 +486,34 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
 	return ret;
 }
 
+static bool vfio_iommu_contained(struct vfio_iommu *iommu)
+{
+	struct vfio_domain *domain = iommu->external_domain;
+	struct vfio_group *group;
+
+	if (!domain)
+		domain = list_first_entry(&iommu->domain_list,
+					  struct vfio_domain, next);
+
+	group = list_first_entry(&domain->group_list, struct vfio_group, next);
+	return vfio_iommu_group_contained(group->iommu_group);
+}
+
+
+bool vfio_vaddr_valid(struct vfio_iommu *iommu, struct vfio_dma *dma)
+{
+	while (dma->suspended) {
+		mutex_unlock(&iommu->lock);
+		msleep_interruptible(10);
+		mutex_lock(&iommu->lock);
+		if (kthread_should_stop() || !vfio_iommu_contained(iommu) ||
+		    fatal_signal_pending(current)) {
+			return false;
+		}
+	}
+	return true;
+}
+
 /*
  * Attempt to pin pages.  We really don't want to track all the pfns and
  * the iommu can only map chunks of consecutive pfns anyway, so get the
@@ -690,6 +720,11 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data,
 			continue;
 		}
 
+		if (!vfio_vaddr_valid(iommu, dma)) {
+			ret = -EFAULT;
+			goto pin_unwind;
+		}
+
 		remote_vaddr = dma->vaddr + (iova - dma->iova);
 		ret = vfio_pin_page_external(dma, remote_vaddr, &phys_pfn[i],
 					     do_accounting);
@@ -1514,12 +1549,16 @@ static int vfio_iommu_replay(struct vfio_iommu *iommu,
 					i += PAGE_SIZE;
 				}
 			} else {
-				unsigned long pfn;
-				unsigned long vaddr = dma->vaddr +
-						     (iova - dma->iova);
+				unsigned long pfn, vaddr;
 				size_t n = dma->iova + dma->size - iova;
 				long npage;
 
+				if (!vfio_vaddr_valid(iommu, dma)) {
+					ret = -EFAULT;
+					goto unwind;
+				}
+				vaddr = dma->vaddr + (iova - dma->iova);
+
 				npage = vfio_pin_pages_remote(dma, vaddr,
 							      n >> PAGE_SHIFT,
 							      &pfn, limit);
@@ -2965,6 +3004,9 @@ static int vfio_iommu_type1_dma_rw_chunk(struct vfio_iommu *iommu,
 	if (count > dma->size - offset)
 		count = dma->size - offset;
 
+	if (!vfio_vaddr_valid(iommu, dma))
+		goto out;
+
 	vaddr = dma->vaddr + offset;
 
 	if (write) {
-- 
1.8.3.1