From: Roger Pau Monné <roger.pau@citrix.com>
Date: Wed, 29 May 2024 14:07:55 +0000 (+0200)
Subject: xen/x86: account number of foreign mappings in the p2m
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=8ef1e96a04fb177c89791749234d873ac883a92a;p=people%2Froyger%2Fxen.git

xen/x86: account number of foreign mappings in the p2m

Such information will be needed in order to remove foreign mappings during
teardown for HVM guests.

Right now the introduced counter is not consumed.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Release-acked-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
---

diff --git a/xen/arch/x86/include/asm/p2m.h b/xen/arch/x86/include/asm/p2m.h
index 111badf89a..107b9f2608 100644
--- a/xen/arch/x86/include/asm/p2m.h
+++ b/xen/arch/x86/include/asm/p2m.h
@@ -380,6 +380,9 @@ struct p2m_domain {
         unsigned int flags;
         unsigned long entry_count;
     } ioreq;
+
+    /* Number of foreign mappings. */
+    unsigned long      nr_foreign;
 #endif /* CONFIG_HVM */
 };
 
@@ -1049,6 +1052,8 @@ static inline int p2m_entry_modify(struct p2m_domain *p2m, p2m_type_t nt,
         if ( !page_get_owner_and_reference(mfn_to_page(nfn)) )
             return -EBUSY;
 
+        p2m->nr_foreign++;
+
         break;
 
     default:
@@ -1069,6 +1074,7 @@ static inline int p2m_entry_modify(struct p2m_domain *p2m, p2m_type_t nt,
             return -EINVAL;
         }
         put_page(mfn_to_page(ofn));
+        p2m->nr_foreign--;
         break;
 
     default: