xen/vtd: create RMRR mapping

RMRR reserved regions must be setup in the pfn space with an identity
mapping to reported mfn. However existing code has problem to setup
correct mapping when VT-d shares EPT page table, so lead to problem
when assigning devices (e.g GPU) with RMRR reported. So instead, this
patch aims to setup identity mapping in p2m layer, regardless of
whether EPT is shared or not. And we still keep creating VT-d table.

And we also need to introduce a pair of helper to create/clear this
sort of identity mapping as follows:

set_identity_p2m_entry():

If the gfn space is unoccupied, we just set the mapping. If space
is already occupied by desired identity mapping, do nothing.
Otherwise, failure is returned.

clear_identity_p2m_entry():

We just define macro to wrapper guest_physmap_remove_page() with
a returning value as necessary.

CC: Tim Deegan <tim@xen.org>
CC: Keir Fraser <keir@xen.org>
CC: Jan Beulich <jbeulich@suse.com>
CC: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Yang Zhang <yang.z.zhang@intel.com>
CC: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Tim Deegan <tim@xen.org>
Acked-by: George Dunlap <george.dunlap@eu.citrix.com>
Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>

diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index 6fe63872d8bc7b8d09535b447c6d45657f27a73c..1e763dcf7a0f3248b586526e5f36c36e7fb3f610 100644 (file)
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -584,14 +584,16 @@ p2m_remove_page(struct p2m_domain *p2m, unsigned long gfn, unsigned long mfn,
                          p2m->default_access);
 }
 
-void
+int
 guest_physmap_remove_page(struct domain *d, unsigned long gfn,
                           unsigned long mfn, unsigned int page_order)
 {
     struct p2m_domain *p2m = p2m_get_hostp2m(d);
+    int rc;
     gfn_lock(p2m, gfn, page_order);
-    p2m_remove_page(p2m, gfn, mfn, page_order);
+    rc = p2m_remove_page(p2m, gfn, mfn, page_order);
     gfn_unlock(p2m, gfn, page_order);
+    return rc;
 }
 
 int
@@ -898,6 +900,40 @@ int set_mmio_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn,
     return set_typed_p2m_entry(d, gfn, mfn, p2m_mmio_direct, access);
 }
 
+int set_identity_p2m_entry(struct domain *d, unsigned long gfn,
+                           p2m_access_t p2ma)
+{
+    p2m_type_t p2mt;
+    p2m_access_t a;
+    mfn_t mfn;
+    struct p2m_domain *p2m = p2m_get_hostp2m(d);
+    int ret;
+
+    if ( !paging_mode_translate(p2m->domain) )
+        return 0;
+
+    gfn_lock(p2m, gfn, 0);
+
+    mfn = p2m->get_entry(p2m, gfn, &p2mt, &a, 0, NULL);
+
+    if ( p2mt == p2m_invalid || p2mt == p2m_mmio_dm )
+        ret = p2m_set_entry(p2m, gfn, _mfn(gfn), PAGE_ORDER_4K,
+                            p2m_mmio_direct, p2ma);
+    else if ( mfn_x(mfn) == gfn && p2mt == p2m_mmio_direct && a == p2ma )
+        ret = 0;
+    else
+    {
+        ret = -EBUSY;
+        printk(XENLOG_G_WARNING
+               "Cannot setup identity map d%d:%lx,"
+               " gfn already mapped to %lx.\n",
+               d->domain_id, gfn, mfn_x(mfn));
+    }
+
+    gfn_unlock(p2m, gfn, 0);
+    return ret;
+}
+
 /* Returns: 0 for success, -errno for failure */
 int clear_mmio_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn)
 {

diff --git a/xen/drivers/passthrough/vtd/iommu.c b/xen/drivers/passthrough/vtd/iommu.c
index 9849d0ee0fdb3c779b2a56dd8156be3650071119..5aa482fe9d329906c5acd2ca9133e5dfef0078aa 100644 (file)
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -1839,7 +1839,7 @@ static int rmrr_identity_mapping(struct domain *d, bool_t map,
 
             while ( base_pfn < end_pfn )
             {
-                if ( intel_iommu_unmap_page(d, base_pfn) )
+                if ( clear_identity_p2m_entry(d, base_pfn, 0) )
                     ret = -ENXIO;
                 base_pfn++;
             }
@@ -1855,8 +1855,7 @@ static int rmrr_identity_mapping(struct domain *d, bool_t map,
 
     while ( base_pfn < end_pfn )
     {
-        int err = intel_iommu_map_page(d, base_pfn, base_pfn,
-                                       IOMMUF_readable|IOMMUF_writable);
+        int err = set_identity_p2m_entry(d, base_pfn, p2m_access_rw);
 
         if ( err )
             return err;

diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h
index b49c09bc3a3b5f3b0c03eac6d97db857309246d5..190a2869f1b284e1d5d46d6c820386fecc5c795a 100644 (file)
--- a/xen/include/asm-x86/p2m.h
+++ b/xen/include/asm-x86/p2m.h
@@ -503,9 +503,9 @@ static inline int guest_physmap_add_page(struct domain *d,
 }
 
 /* Remove a page from a domain's p2m table */
-void guest_physmap_remove_page(struct domain *d,
-                               unsigned long gfn,
-                               unsigned long mfn, unsigned int page_order);
+int guest_physmap_remove_page(struct domain *d,
+                              unsigned long gfn,
+                              unsigned long mfn, unsigned int page_order);
 
 /* Set a p2m range as populate-on-demand */
 int guest_physmap_mark_populate_on_demand(struct domain *d, unsigned long gfn,
@@ -543,6 +543,13 @@ int set_mmio_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn,
                        p2m_access_t access);
 int clear_mmio_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn);
 
+/* Set identity addresses in the p2m table (for pass-through) */
+int set_identity_p2m_entry(struct domain *d, unsigned long gfn,
+                           p2m_access_t p2ma);
+
+#define clear_identity_p2m_entry(d, gfn, page_order) \
+                        guest_physmap_remove_page(d, gfn, gfn, page_order)
+
 /* Add foreign mapping to the guest's p2m table. */
 int p2m_add_foreign(struct domain *tdom, unsigned long fgfn,
                     unsigned long gpfn, domid_t foreign_domid);