[Xen-changelog] [xen master] x86: machine_restart() must not call acpi_dmar_reinstate() twice

[patchbot@xxxxxxx]

commit a54dc5f4fe1eae6b1beb21326ef0338cd3969cd1
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Fri Sep 13 14:27:34 2013 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri Sep 13 14:27:34 2013 +0200

    x86: machine_restart() must not call acpi_dmar_reinstate() twice
    
    .. as that function is not idempotent (it always alters the table
    checksum). The (generally) duplicate call was a result from it being
    made before machine_restart() re-invoking itself on the boot CPU.
    
    Considering that no problem arose so far from the table corruption I
    doubt that we need to restore the correct table signature on the
    reboot path in general. The only case I can see this as potentially
    necessary is the tboot one, hence do the call just in that case.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Keir Fraser <keir@xxxxxxx>
---
 xen/arch/x86/shutdown.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/shutdown.c b/xen/arch/x86/shutdown.c
index 167905a..6eba271 100644
--- a/xen/arch/x86/shutdown.c
+++ b/xen/arch/x86/shutdown.c
@@ -466,8 +466,6 @@ void machine_restart(unsigned int delay_millisecs)
     console_start_sync();
     spin_debug_disable();
 
-    acpi_dmar_reinstate();
-
     local_irq_enable();
 
     /* Ensure we are the boot CPU. */
@@ -492,7 +490,10 @@ void machine_restart(unsigned int delay_millisecs)
     mdelay(delay_millisecs);
 
     if ( tboot_in_measured_env() )
+    {
+        acpi_dmar_reinstate();
         tboot_shutdown(TB_SHUTDOWN_REBOOT);
+    }
 
     efi_reset_system(reboot_mode != 0);
 
--
generated by git-patchbot for /home/xen/git/xen.git#master

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