[Xen-changelog] [xen master] vmx: fix handling of NMI VMEXIT.

[patchbot@xxxxxxx]

commit 7dd3b06ff031c9a8c727df16c5def2afb382101c
Author:     Tim Deegan <tim@xxxxxxx>
AuthorDate: Thu Feb 28 12:42:15 2013 +0000
Commit:     Tim Deegan <tim@xxxxxxx>
CommitDate: Thu Feb 28 14:00:18 2013 +0000

    vmx: fix handling of NMI VMEXIT.
    
    Call do_nmi() directly and explicitly re-enable NMIs rather than
    raising an NMI through the APIC. Since NMIs are disabled after the
    VMEXIT, the raised NMI would be blocked until the next IRET
    instruction (i.e. the next real interrupt, or after scheduling a PV
    guest) and in the meantime the guest will spin taking NMI VMEXITS.
    
    Also, handle NMIs before re-enabling interrupts, since if we handle an
    interrupt (and therefore IRET) before calling do_nmi(), we may end up
    running the NMI handler with NMIs enabled.
    
    Signed-off-by: Tim Deegan <tim@xxxxxxx>
    Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vmx.c |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 5378928..04dbefb 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -2313,6 +2313,13 @@ void vmx_vmexit_handler(struct cpu_user_regs *regs)
         vector = intr_info & INTR_INFO_VECTOR_MASK;
         if ( vector == TRAP_machine_check )
             do_machine_check(regs);
+        if ( vector == TRAP_nmi
+             && ((intr_info & INTR_INFO_INTR_TYPE_MASK) ==
+                 (X86_EVENTTYPE_NMI << 8)) )
+        {
+            do_nmi(regs);
+            enable_nmis();
+        }
         break;
     case EXIT_REASON_MCE_DURING_VMENTRY:
         do_machine_check(regs);
@@ -2486,7 +2493,7 @@ void vmx_vmexit_handler(struct cpu_user_regs *regs)
                  (X86_EVENTTYPE_NMI << 8) )
                 goto exit_and_crash;
             HVMTRACE_0D(NMI);
-            self_nmi(); /* Real NMI, vector 2: normal processing. */
+            /* Already handled above. */
             break;
         case TRAP_machine_check:
             HVMTRACE_0D(MCE);
--
generated by git-patchbot for /home/xen/git/xen.git#master

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