[Xen-changelog] [xen-unstable] x86/hvm: refactor calls to prepare and tear down a helper ring

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User Tim Deegan <tim@xxxxxxx>
# Date 1331224805 0
# Node ID 29c29f7a525c64ebe53d4b0fadd701302a396a06
# Parent  e639e75254e9cdc95c4957c1517c145222e79f3e
x86/hvm: refactor calls to prepare and tear down a helper ring

These are currently used for the rings connecting Xen with qemu. Refactor them
so the same code can be later used for mem event rings.

Signed-off-by: Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>
Acked-by: Tim Deegan <tim@xxxxxxx>
Committed-by: Tim Deegan <tim@xxxxxxx>
---


diff -r e639e75254e9 -r 29c29f7a525c xen/arch/x86/hvm/hvm.c
--- a/xen/arch/x86/hvm/hvm.c    Thu Mar 08 16:40:05 2012 +0000
+++ b/xen/arch/x86/hvm/hvm.c    Thu Mar 08 16:40:05 2012 +0000
@@ -339,6 +339,19 @@
     domain_pause(d);
 }
 
+void destroy_ring_for_helper(
+    void **_va, struct page_info *page)
+{
+    void *va = *_va;
+
+    if ( va != NULL )
+    {
+        unmap_domain_page_global(va);
+        put_page_and_type(page);
+        *_va = NULL;
+    }
+}
+
 static void hvm_destroy_ioreq_page(
     struct domain *d, struct hvm_ioreq_page *iorp)
 {
@@ -346,18 +359,14 @@
 
     ASSERT(d->is_dying);
 
-    if ( iorp->va != NULL )
-    {
-        unmap_domain_page_global(iorp->va);
-        put_page_and_type(iorp->page);
-        iorp->va = NULL;
-    }
+    destroy_ring_for_helper(&iorp->va, iorp->page);
 
     spin_unlock(&iorp->lock);
 }
 
-static int hvm_set_ioreq_page(
-    struct domain *d, struct hvm_ioreq_page *iorp, unsigned long gmfn)
+int prepare_ring_for_helper(
+    struct domain *d, unsigned long gmfn, struct page_info **_page,
+    void **_va)
 {
     struct page_info *page;
     p2m_type_t p2mt;
@@ -398,14 +407,30 @@
         return -ENOMEM;
     }
 
+    *_va = va;
+    *_page = page;
+
+    put_gfn(d, gmfn);
+
+    return 0;
+}
+
+static int hvm_set_ioreq_page(
+    struct domain *d, struct hvm_ioreq_page *iorp, unsigned long gmfn)
+{
+    struct page_info *page;
+    void *va;
+    int rc;
+
+    if ( (rc = prepare_ring_for_helper(d, gmfn, &page, &va)) )
+        return rc;
+
     spin_lock(&iorp->lock);
 
     if ( (iorp->va != NULL) || d->is_dying )
     {
+        destroy_ring_for_helper(&iorp->va, iorp->page);
         spin_unlock(&iorp->lock);
-        unmap_domain_page_global(va);
-        put_page_and_type(mfn_to_page(mfn));
-        put_gfn(d, gmfn);
         return -EINVAL;
     }
 
@@ -413,7 +438,6 @@
     iorp->page = page;
 
     spin_unlock(&iorp->lock);
-    put_gfn(d, gmfn);
 
     domain_unpause(d);
 
diff -r e639e75254e9 -r 29c29f7a525c xen/include/asm-x86/hvm/hvm.h
--- a/xen/include/asm-x86/hvm/hvm.h     Thu Mar 08 16:40:05 2012 +0000
+++ b/xen/include/asm-x86/hvm/hvm.h     Thu Mar 08 16:40:05 2012 +0000
@@ -26,6 +26,7 @@
 #include <asm/hvm/asid.h>
 #include <public/domctl.h>
 #include <public/hvm/save.h>
+#include <asm/mm.h>
 
 /* Interrupt acknowledgement sources. */
 enum hvm_intsrc {
@@ -191,6 +192,12 @@
 void hvm_vcpu_cacheattr_destroy(struct vcpu *v);
 void hvm_vcpu_reset_state(struct vcpu *v, uint16_t cs, uint16_t ip);
 
+/* Prepare/destroy a ring for a dom0 helper. Helper with talk
+ * with Xen on behalf of this hvm domain. */
+int prepare_ring_for_helper(struct domain *d, unsigned long gmfn, 
+                            struct page_info **_page, void **_va);
+void destroy_ring_for_helper(void **_va, struct page_info *page);
+
 bool_t hvm_send_assist_req(struct vcpu *v);
 
 void hvm_set_guest_tsc(struct vcpu *v, u64 guest_tsc);

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