[Xen-changelog] [xen staging] x86emul: VME and PVI modes require a #GP(0) check first thing

[patchbot@xxxxxxx]

commit efe9cba66c036c452cc2ed7220984aa11be8dcb5
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Mon Nov 5 11:13:59 2018 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Nov 5 11:13:59 2018 +0100

    x86emul: VME and PVI modes require a #GP(0) check first thing
    
    As explicitly spelled out by the SDM, EFLAGS.VIF and EFLAGS.VIP both set
    at the start of an instruction trigger #GP(0) independent of actual
    instruction.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/x86_emulate/x86_emulate.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c 
b/xen/arch/x86/x86_emulate/x86_emulate.c
index e717e6ac14..e69dfdd983 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -3247,6 +3247,11 @@ x86_emulate(
 
     ASSERT(ops->read);
 
+    generate_exception_if((mode_vif() &&
+                           (_regs.eflags & X86_EFLAGS_VIF) &&
+                           (_regs.eflags & X86_EFLAGS_VIP)),
+                          EXC_GP, 0);
+
     rc = x86_decode(&state, ctxt, ops);
     if ( rc != X86EMUL_OKAY )
         return rc;
--
generated by git-patchbot for /home/xen/git/xen.git#staging

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