[Xen-changelog] [xen master] x86/PVH: allow guest_remove_page to remove p2m_mmio_direct pages

[patchbot@xxxxxxx]

commit 48dfb297a20a8a37de2db45710e3c42db014e7ef
Author:     Roger Pau Monné <roger.pau@xxxxxxxxxx>
AuthorDate: Fri Jun 20 10:38:07 2014 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri Jun 20 10:38:07 2014 +0200

    x86/PVH: allow guest_remove_page to remove p2m_mmio_direct pages
    
    IF a guest tries to do a foreign/grant mapping in a memory region
    marked as p2m_mmio_direct Xen will complain with the following
    message:
    
    (XEN) memory.c:241:d0v0 Bad page free for domain 0
    
    Albeit the mapping will succeed. This is specially problematic for PVH
    Dom0, in which we map all the e820 holes and memory up to 4GB as
    p2m_mmio_direct.
    
    In order to deal with it, add a special casing for p2m_mmio_direct
    regions in guest_remove_page if the domain is a hardware domain, that
    calls clear_mmio_p2m_entry in order to remove the mappings.
    
    Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Acked-by: Tim Deegan <tim@xxxxxxx>
---
 xen/common/memory.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/xen/common/memory.c b/xen/common/memory.c
index 257f4b0..c2dd31b 100644
--- a/xen/common/memory.c
+++ b/xen/common/memory.c
@@ -204,6 +204,12 @@ int guest_remove_page(struct domain *d, unsigned long gmfn)
         p2m_mem_paging_drop_page(d, gmfn, p2mt);
         return 1;
     }
+    if ( p2mt == p2m_mmio_direct )
+    {
+        clear_mmio_p2m_entry(d, gmfn);
+        put_gfn(d, gmfn);
+        return 1;
+    }
 #else
     mfn = gmfn_to_mfn(d, gmfn);
 #endif
--
generated by git-patchbot for /home/xen/git/xen.git#master

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