[Xen-devel] [PATCH v2 07/13] iommu: Make decision about needing IOMMU for hardware domains in advance

[Oleksandr Tyshchenko <olekstysh@xxxxxxxxx>]

From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>

The hardware domains require IOMMU to be used in the most cases and
a decision to use it is made at hardware domain construction time.
But, it is not the best moment for the non-shared IOMMUs due to
the necessity of retrieving all mapping which could happen in a period
of time between IOMMU per-domain initialization and this moment.

So, make a decision about needing IOMMU a bit earlier, in iommu_domain_init().
Having "d->need_iommu" flag set at the early stage we won't skip
any IOMMU mapping updates. And as the result the existing in iommu_hwdom_init()
code that goes through the list of the pages and tries to retrieve mapping
for non-shared IOMMUs won't be needed anymore and can be just dropped.

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
CC: Jan Beulich <jbeulich@xxxxxxxx>
CC: Julien Grall <julien.grall@xxxxxxx>

---
Changes in v1:
   -

Changes in v2:
   - This is the result of reworking old patch:
     [PATCH v1 08/10] iommu: Split iommu_hwdom_init() into arch specific parts
---
 xen/drivers/passthrough/iommu.c | 44 ++++++++++-------------------------------
 1 file changed, 10 insertions(+), 34 deletions(-)

diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c
index 19c87d1..f5e5b7e 100644
--- a/xen/drivers/passthrough/iommu.c
+++ b/xen/drivers/passthrough/iommu.c
@@ -52,7 +52,7 @@ custom_param("iommu", parse_iommu_param);
 bool_t __initdata iommu_enable = 1;
 bool_t __read_mostly iommu_enabled;
 bool_t __read_mostly force_iommu;
-bool_t __hwdom_initdata iommu_dom0_strict;
+bool_t __read_mostly iommu_dom0_strict;
 bool_t __read_mostly iommu_verbose;
 bool_t __read_mostly iommu_workaround_bios_bug;
 bool_t __read_mostly iommu_igfx = 1;
@@ -141,6 +141,15 @@ int iommu_domain_init(struct domain *d, bool use_iommu)
     if ( !iommu_enabled )
         return 0;
 
+    if ( is_hardware_domain(d) )
+    {
+        if ( (paging_mode_translate(d) && !iommu_passthrough) ||
+              iommu_dom0_strict )
+            use_iommu = 1;
+        else
+            use_iommu = 0;
+    }
+
     hd->platform_ops = iommu_get_ops();
     ret = hd->platform_ops->init(d, use_iommu);
     if ( ret )
@@ -161,8 +170,6 @@ static void __hwdom_init check_hwdom_reqs(struct domain *d)
     if ( iommu_passthrough )
         panic("Dom0 uses paging translated mode, dom0-passthrough must not be "
               "enabled\n");
-
-    iommu_dom0_strict = 1;
 }
 
 void __hwdom_init iommu_hwdom_init(struct domain *d)
@@ -175,37 +182,6 @@ void __hwdom_init iommu_hwdom_init(struct domain *d)
         return;
 
     register_keyhandler('o', &iommu_dump_p2m_table, "dump iommu p2m table", 0);
-    d->need_iommu = !!iommu_dom0_strict;
-    if ( need_iommu(d) && !iommu_use_hap_pt(d) )
-    {
-        struct page_info *page;
-        unsigned int i = 0;
-        int rc = 0;
-
-        page_list_for_each ( page, &d->page_list )
-        {
-            unsigned long mfn = page_to_mfn(page);
-            unsigned long gfn = mfn_to_gmfn(d, mfn);
-            unsigned int mapping = IOMMUF_readable;
-            int ret;
-
-            if ( ((page->u.inuse.type_info & PGT_count_mask) == 0) ||
-                 ((page->u.inuse.type_info & PGT_type_mask)
-                  == PGT_writable_page) )
-                mapping |= IOMMUF_writable;
-
-            ret = hd->platform_ops->map_pages(d, gfn, mfn, 0, mapping);
-            if ( !rc )
-                rc = ret;
-
-            if ( !(i++ & 0xfffff) )
-                process_pending_softirqs();
-        }
-
-        if ( rc )
-            printk(XENLOG_WARNING "d%d: IOMMU mapping failed: %d\n",
-                   d->domain_id, rc);
-    }
 
     return hd->platform_ops->hwdom_init(d);
 }
-- 
2.7.4


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel