[xen staging] xen/arm: allow translated iommu mappings

[patchbot@xxxxxxx]

commit 4cde4a552ed35f3cc74df877d5a7cfbbfced8fb3
Author:     Stefano Stabellini <stefano.stabellini@xxxxxxx>
AuthorDate: Fri Jul 25 10:01:26 2025 -0400
Commit:     Julien Grall <jgrall@xxxxxxxxxx>
CommitDate: Tue Aug 12 12:04:41 2025 +0100

    xen/arm: allow translated iommu mappings
    
    In preparation of exposing vITS to domUs, generalize arm_iommu_map_page
    and arm_iommu_unmap_page to allow ITS doorbell mappings with dfn != mfn.
    
    The mfn does not need to be passed to guest_physmap_remove_page since
    there is no mfn checking on the p2m_iommu_map_{rw,ro} p2m types during
    unmap. Pass INVALID_MFN to guest_physmap_remove_page.
    
    Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxx>
    Signed-off-by: Stewart Hildebrand <stewart.hildebrand@xxxxxxx>
    Tested-by: Jason Andryuk <jason.andryuk@xxxxxxx>
    Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx>
---
 xen/drivers/passthrough/arm/iommu_helpers.c | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/xen/drivers/passthrough/arm/iommu_helpers.c 
b/xen/drivers/passthrough/arm/iommu_helpers.c
index bdb271584b..a3e3cafb87 100644
--- a/xen/drivers/passthrough/arm/iommu_helpers.c
+++ b/xen/drivers/passthrough/arm/iommu_helpers.c
@@ -36,9 +36,6 @@ int __must_check arm_iommu_map_page(struct domain *d, dfn_t 
dfn, mfn_t mfn,
 {
     p2m_type_t t;
 
-    BUG_ON(!domain_use_host_layout(d));
-    BUG_ON(mfn_x(mfn) != dfn_x(dfn));
-
     /* We only support readable and writable flags */
     if ( !(flags & (IOMMUF_readable | IOMMUF_writable)) )
         return -EINVAL;
@@ -49,7 +46,7 @@ int __must_check arm_iommu_map_page(struct domain *d, dfn_t 
dfn, mfn_t mfn,
      * The function guest_physmap_add_entry replaces the current mapping
      * if there is already one...
      */
-    return guest_physmap_add_entry(d, _gfn(dfn_x(dfn)), _mfn(dfn_x(dfn)),
+    return guest_physmap_add_entry(d, _gfn(dfn_x(dfn)), mfn,
                                    IOMMUF_order(flags), t);
 }
 
@@ -58,11 +55,7 @@ int __must_check arm_iommu_unmap_page(struct domain *d, 
dfn_t dfn,
                                       unsigned int order,
                                       unsigned int *flush_flags)
 {
-    if ( !domain_use_host_layout(d) )
-        return -EINVAL;
-
-    return guest_physmap_remove_page(d, _gfn(dfn_x(dfn)), _mfn(dfn_x(dfn)),
-                                     order);
+    return guest_physmap_remove_page(d, _gfn(dfn_x(dfn)), INVALID_MFN, order);
 }
 
 /*
--
generated by git-patchbot for /home/xen/git/xen.git#staging