[Xen-devel] NMI delivery not correctly working

["Christoph Egger" <Christoph.Egger@xxxxxxx>]

Hi!

The NMI delivery does not work correctly.

In the section process_nmi: in
xen/arch/x86/x86_(32|64)/entry.S you set a bit in VCPU_nmi_masked,
deliver the NMI but not clear VCPU_nmi_masked.

I know, there is a line "current->nmi_masked = 0;" in do_iret() in
xen/arch/x86/x86_(32|64)/traps.c, but this is actually never called
after NMI delivery.

For short: The *first* NMI is actually delivered, but all following NMIs
are NEVER delivered!!

I don't know if this change is correct for 64 bit:

@@ -218,6 +220,7 @@ process_nmi:
         movq %rax,TRAPBOUNCE_eip(%rdx)
         movb $TBF_INTERRUPT,TRAPBOUNCE_flags(%rdx)
         call create_bounce_frame
+        movb  $0, VCPU_nmi_masked(%rbx)
         jmp  test_all_events


and for 32 bit:

@@ -261,6 +262,7 @@ process_nmi:
         movw $FLAT_KERNEL_CS,TRAPBOUNCE_cs(%edx)
         movb $TBF_INTERRUPT,TRAPBOUNCE_flags(%edx)
         call create_bounce_frame
+        movb $0,VCPU_nmi_masked(%ebx)
         jmp  test_all_events

but NMI delivery seems to work with these changes.


Christoph



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