[Xen-changelog] [xen staging] x86/HVM: make hvmemul_map_linear_addr() honor p2m_ioreq_server

[patchbot@xxxxxxx]

commit bfdd5e58763a32afdf04b022e2698d39ae4cf4d6
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Thu Nov 15 13:36:10 2018 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Nov 15 13:36:10 2018 +0100

    x86/HVM: make hvmemul_map_linear_addr() honor p2m_ioreq_server
    
    Write accesses to p2m_ioreq_server pages should get redirected to the
    emulator also when using the mapping approach. Extend the
    p2m_is_discard_write() check there, and restrict both to the write
    access case (this is just a latent bug as currently we go this route
    only for write accesses).
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
---
 xen/arch/x86/hvm/emulate.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index 9e7deaa6cd..e08524be49 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -613,10 +613,21 @@ static void *hvmemul_map_linear_addr(
 
         *mfn++ = page_to_mfn(page);
 
-        if ( p2m_is_discard_write(p2mt) )
+        if ( pfec & PFEC_write_access )
         {
-            err = ERR_PTR(~X86EMUL_OKAY);
-            goto out;
+            if ( p2m_is_discard_write(p2mt) )
+            {
+                err = ERR_PTR(~X86EMUL_OKAY);
+                goto out;
+            }
+
+            if ( p2mt == p2m_ioreq_server )
+            {
+                err = NULL;
+                goto out;
+            }
+
+            ASSERT(p2mt == p2m_ram_logdirty || !p2m_is_readonly(p2mt));
         }
     }
 
--
generated by git-patchbot for /home/xen/git/xen.git#staging

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