[Xen-devel] [PATCH v1] Fix p2m_set_suppress_ve

[Alexandru Stefan ISAILA <aisaila@xxxxxxxxxxxxxxx>]

On a new altp2m view the p2m_set_suppress_ve() func will fail with invalid mfn
from p2m->get_entry() if the p2m->set_entry() was not called before.

This patch solves the problem by getting the mfn from __get_gfn_type_access()
and then returning error if the mfn is invalid.

Signed-off-by: Alexandru Isaila <aisaila@xxxxxxxxxxxxxxx>
---
 xen/arch/x86/mm/p2m.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index b9bbb8f485..3e6e5ef152 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -3011,8 +3011,16 @@ int p2m_set_suppress_ve(struct domain *d, gfn_t gfn, 
bool suppress_ve,
     mfn = p2m->get_entry(p2m, gfn, &t, &a, 0, NULL, NULL);
     if ( !mfn_valid(mfn) )
     {
-        rc = -ESRCH;
-        goto out;
+        unsigned int page_order;
+
+        mfn = __get_gfn_type_access(host_p2m, gfn_x(gfn), &t, &a,
+                                    P2M_ALLOC | P2M_UNSHARE, &page_order, 0);
+
+        if ( !mfn_valid(mfn) )
+        {
+            rc = -ESRCH;
+            goto out;
+        }
     }
 
     rc = p2m->set_entry(p2m, gfn, mfn, PAGE_ORDER_4K, t, a, suppress_ve);
-- 
2.17.1


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