[PATCH v2 05/25] arm/altp2m: Rename and extend p2m_alloc_table.

[Sergej Proskurin <proskurin@sec.in.tum.de>]

The initially named function "p2m_alloc_table" allocated pages solely
required for the host's p2m. The new implementation leaves p2m
allocation related parts inside of this function to generally initialize
p2m/altp2m tables. This is done generically, as the host's p2m and
altp2m tables are allocated similarly. Since this function will be used
by the altp2m initialization routines, it is not made static. In
addition, this commit provides the overlay function "p2m_table_init"
that is used for the host's p2m allocation/initialization.

Signed-off-by: Sergej Proskurin <proskurin@sec.in.tum.de>
---
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Julien Grall <julien.grall@arm.com>
---
v2: Removed altp2m table initialization from "p2m_table_init".
---
 xen/arch/arm/p2m.c | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 17f3299..63fe3d9 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -1277,11 +1277,11 @@ void guest_physmap_remove_page(struct domain *d,
     p2m_remove_mapping(d, gfn, (1 << page_order), mfn);
 }
 
-static int p2m_alloc_table(struct domain *d)
+int p2m_alloc_table(struct p2m_domain *p2m)
 {
-    struct p2m_domain *p2m = &d->arch.p2m;
-    struct page_info *page;
     unsigned int i;
+    struct page_info *page;
+    struct vttbr *vttbr = &p2m->vttbr;
 
     page = alloc_domheap_pages(NULL, P2M_ROOT_ORDER, 0);
     if ( page == NULL )
@@ -1293,11 +1293,28 @@ static int p2m_alloc_table(struct domain *d)
 
     p2m->root = page;
 
-    p2m->vttbr.vttbr = page_to_maddr(p2m->root) | ((uint64_t)p2m->vmid & 0xff) << 48;
+    /* Initialize the VTTBR associated with the allocated p2m table. */
+    vttbr->vttbr = 0;
+    vttbr->vmid = p2m->vmid & 0xff;
+    vttbr->baddr = page_to_maddr(p2m->root);
+
+    return 0;
+}
+
+static int p2m_table_init(struct domain *d)
+{
+    int rc;
+    struct p2m_domain *p2m = p2m_get_hostp2m(d);
+
+    rc = p2m_alloc_table(p2m);
+    if ( rc != 0 )
+        return -ENOMEM;
+
+    d->arch.altp2m_active = false;
 
     /*
      * Make sure that all TLBs corresponding to the new VMID are flushed
-     * before using it
+     * before using it.
      */
     p2m_flush_tlb(p2m);
 
@@ -1440,7 +1457,7 @@ static int p2m_init_hostp2m(struct domain *d)
     if ( rc )
         return rc;
 
-    return p2m_alloc_table(d);
+    return p2m_table_init(d);
 }
 
 int p2m_init(struct domain *d)
-- 
2.9.0


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