[Xen-devel] [PATCH v2 04/25] arm/altp2m: Move hostp2m init/teardown to individual functions.

[Sergej Proskurin <proskurin@xxxxxxxxxxxxx>]

This commit pulls out generic init/teardown functionality out of
p2m_init and p2m_teardown into p2m_init_one, p2m_free_one, and
p2m_flush_table functions.  This allows our future implementation to
reuse existing code for the initialization/teardown of altp2m views.

Signed-off-by: Sergej Proskurin <proskurin@xxxxxxxxxxxxx>
---
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Julien Grall <julien.grall@xxxxxxx>
---
v2: Added the function p2m_flush_table to the previous version.
---
 xen/arch/arm/p2m.c        | 74 +++++++++++++++++++++++++++++++++++++----------
 xen/include/asm-arm/p2m.h | 11 +++++++
 2 files changed, 70 insertions(+), 15 deletions(-)

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index cbc64a1..17f3299 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -1360,50 +1360,94 @@ static void p2m_free_vmid(struct domain *d)
     spin_unlock(&vmid_alloc_lock);
 }
 
-void p2m_teardown(struct domain *d)
+/* Reset this p2m table to be empty */
+void p2m_flush_table(struct p2m_domain *p2m)
 {
-    struct p2m_domain *p2m = &d->arch.p2m;
-    struct page_info *pg;
+    struct page_info *page, *pg;
+    unsigned int i;
+
+    page = p2m->root;
+
+    /* Clear all concatenated first level pages */
+    for ( i = 0; i < P2M_ROOT_PAGES; i++ )
+        clear_and_clean_page(page + i);
 
+    /* Free the rest of the trie pages back to the paging pool */
     while ( (pg = page_list_remove_head(&p2m->pages)) )
         free_domheap_page(pg);
+}
+
+static inline void p2m_free_one(struct p2m_domain *p2m)
+{
+    p2m_flush_table(p2m);
+
+    /* Free VMID and reset VTTBR */
+    p2m_free_vmid(p2m->domain);
+    p2m->vttbr.vttbr = INVALID_VTTBR;
 
     if ( p2m->root )
         free_domheap_pages(p2m->root, P2M_ROOT_ORDER);
 
     p2m->root = NULL;
 
-    p2m_free_vmid(d);
-
     radix_tree_destroy(&p2m->mem_access_settings, NULL);
 }
 
-int p2m_init(struct domain *d)
+int p2m_init_one(struct domain *d, struct p2m_domain *p2m)
 {
-    struct p2m_domain *p2m = &d->arch.p2m;
     int rc = 0;
 
     rwlock_init(&p2m->lock);
     INIT_PAGE_LIST_HEAD(&p2m->pages);
 
-    p2m->vmid = INVALID_VMID;
-
     rc = p2m_alloc_vmid(d);
     if ( rc != 0 )
         return rc;
 
-    p2m->max_mapped_gfn = _gfn(0);
-    p2m->lowest_mapped_gfn = _gfn(ULONG_MAX);
-
-    p2m->default_access = p2m_access_rwx;
+    p2m->domain = d;
+    p2m->access_required = false;
     p2m->mem_access_enabled = false;
+    p2m->default_access = p2m_access_rwx;
+    p2m->root = NULL;
+    p2m->max_mapped_gfn = _gfn(0);
+    p2m->lowest_mapped_gfn = INVALID_GFN;
+    p2m->vttbr.vttbr = INVALID_VTTBR;
     radix_tree_init(&p2m->mem_access_settings);
 
-    rc = p2m_alloc_table(d);
-
     return rc;
 }
 
+static void p2m_teardown_hostp2m(struct domain *d)
+{
+    struct p2m_domain *p2m = p2m_get_hostp2m(d);
+
+    p2m_free_one(p2m);
+}
+
+void p2m_teardown(struct domain *d)
+{
+    p2m_teardown_hostp2m(d);
+}
+
+static int p2m_init_hostp2m(struct domain *d)
+{
+    int rc;
+    struct p2m_domain *p2m = p2m_get_hostp2m(d);
+
+    p2m->p2m_class = p2m_host;
+
+    rc = p2m_init_one(d, p2m);
+    if ( rc )
+        return rc;
+
+    return p2m_alloc_table(d);
+}
+
+int p2m_init(struct domain *d)
+{
+    return p2m_init_hostp2m(d);
+}
+
 int relinquish_p2m_mapping(struct domain *d)
 {
     struct p2m_domain *p2m = &d->arch.p2m;
diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h
index 5c7cd1a..1f9c370 100644
--- a/xen/include/asm-arm/p2m.h
+++ b/xen/include/asm-arm/p2m.h
@@ -18,6 +18,11 @@ struct domain;
 
 extern void memory_type_changed(struct domain *);
 
+typedef enum {
+    p2m_host,
+    p2m_alternate,
+} p2m_class_t;
+
 /* Per-p2m-table state */
 struct p2m_domain {
     /* Lock that protects updates to the p2m */
@@ -78,6 +83,12 @@ struct p2m_domain {
      * enough available bits to store this information.
      */
     struct radix_tree_root mem_access_settings;
+
+    /* Choose between: host/alternate */
+    p2m_class_t p2m_class;
+
+    /* Back pointer to domain */
+    struct domain *domain;
 };
 
 /*
-- 
2.9.0


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