[RFC] iommu/virtio: Add map/unmap_pages() callbacks implementation

[RFC] iommu/virtio: Add map/unmap_pages() callbacks implementation

[Tina Zhang]

From: Tina Zhang <tina.zhang@intel.com>

Map/unmap_pags() allows map and unmap multiple pages of the same size
in one call, which can improve performance by reducing the numbers of
vmexits. With map/unmap_pages() implemented, the prior map/unmap()
callbacks are deprecated.

Signed-off-by: Tina Zhang <tina.zhang@intel.com>
---
 drivers/iommu/virtio-iommu.c | 31 +++++++++++++++++++++++++++++--
 1 file changed, 29 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index 25be4b822aa0..f6e672b13bdc 100644
--- a/drivers/iommu/virtio-iommu.c
+++ b/drivers/iommu/virtio-iommu.c
@@ -1006,6 +1006,33 @@ static int viommu_of_xlate(struct device *dev, struct of_phandle_args *args)
 	return iommu_fwspec_add_ids(dev, args->args, 1);
 }
 
+static int viommu_map_pages(struct iommu_domain *domain,
+				 unsigned long iova, phys_addr_t paddr,
+				 size_t pgsize, size_t pgcount,
+				 int prot, gfp_t gfp, size_t *mapped)
+{
+	unsigned long pgshift = __ffs(pgsize);
+	size_t size = pgcount << pgshift;
+	int ret;
+
+	ret = viommu_map(domain, iova, paddr, size, prot, gfp);
+	if (!ret && mapped)
+		*mapped = size;
+
+	return ret;
+}
+
+static size_t viommu_unmap_pages(struct iommu_domain *domain,
+				      unsigned long iova,
+				      size_t pgsize, size_t pgcount,
+				      struct iommu_iotlb_gather *gather)
+{
+	unsigned long pgshift = __ffs(pgsize);
+	size_t size = pgcount << pgshift;
+
+	return viommu_unmap(domain, iova, size, gather);
+}
+
 static struct iommu_ops viommu_ops = {
 	.domain_alloc		= viommu_domain_alloc,
 	.probe_device		= viommu_probe_device,
@@ -1018,8 +1045,8 @@ static struct iommu_ops viommu_ops = {
 	.owner			= THIS_MODULE,
 	.default_domain_ops = &(const struct iommu_domain_ops) {
 		.attach_dev		= viommu_attach_dev,
-		.map			= viommu_map,
-		.unmap			= viommu_unmap,
+		.unmap_pages		= viommu_unmap_pages,
+		.map_pages		= viommu_map_pages,
 		.iova_to_phys		= viommu_iova_to_phys,
 		.iotlb_sync		= viommu_iotlb_sync,
 		.free			= viommu_domain_free,
-- 
2.25.1

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