[Xen-changelog] [xen master] x86/emul: Avoid raising faults behind the emulators back

[patchbot@xxxxxxx]

commit 331d781400bee90c62ba2bb1caaed55ccba93aba
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Tue Nov 1 19:50:47 2016 +0000
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Fri Dec 2 17:23:02 2016 +0000

    x86/emul: Avoid raising faults behind the emulators back
    
    Introduce a new x86_emul_pagefault() similar to x86_emul_hw_exception(), and
    use this instead of hvm_inject_page_fault() from emulation codepaths.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/hvm/emulate.c             |  4 ++--
 xen/arch/x86/x86_emulate/x86_emulate.h | 13 +++++++++++++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index 4b8c9a0..614e182 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -459,7 +459,7 @@ static int hvmemul_linear_to_phys(
     {
         if ( pfec & (PFEC_page_paged | PFEC_page_shared) )
             return X86EMUL_RETRY;
-        hvm_inject_page_fault(pfec, addr);
+        x86_emul_pagefault(pfec, addr, &hvmemul_ctxt->ctxt);
         return X86EMUL_EXCEPTION;
     }
 
@@ -483,7 +483,7 @@ static int hvmemul_linear_to_phys(
                 ASSERT(!reverse);
                 if ( npfn != gfn_x(INVALID_GFN) )
                     return X86EMUL_UNHANDLEABLE;
-                hvm_inject_page_fault(pfec, addr & PAGE_MASK);
+                x86_emul_pagefault(pfec, addr & PAGE_MASK, 
&hvmemul_ctxt->ctxt);
                 return X86EMUL_EXCEPTION;
             }
             *reps = done;
diff --git a/xen/arch/x86/x86_emulate/x86_emulate.h 
b/xen/arch/x86/x86_emulate/x86_emulate.h
index a397cc9..915c1fe 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.h
+++ b/xen/arch/x86/x86_emulate/x86_emulate.h
@@ -648,6 +648,19 @@ static inline void x86_emul_hw_exception(
     ctxt->event_pending = true;
 }
 
+static inline void x86_emul_pagefault(
+    int error_code, unsigned long cr2, struct x86_emulate_ctxt *ctxt)
+{
+    ASSERT(!ctxt->event_pending);
+
+    ctxt->event.vector = 14; /* TRAP_page_fault */
+    ctxt->event.type = X86_EVENTTYPE_HW_EXCEPTION;
+    ctxt->event.error_code = error_code;
+    ctxt->event.cr2 = cr2;
+
+    ctxt->event_pending = true;
+}
+
 static inline void x86_emul_software_event(
     enum x86_swint_type type, uint8_t vector, uint8_t insn_len,
     struct x86_emulate_ctxt *ctxt)
--
generated by git-patchbot for /home/xen/git/xen.git#master

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