x86: UV: Address interrupt/IO port operation conflict

This patch for SGI UV systems addresses a problem whereby
interrupt transactions being looped back from a local IOH,
through the hub to a local CPU can (erroneously) conflict with
IO port operations and other transactions.

To workaound this we set a high bit in the APIC IDs used for
interrupts. This bit appears to be ignored by the sockets, but
it avoids the conflict in the hub.

Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
LKML-Reference: <20101116222352.GA8155@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
___

 arch/x86/include/asm/uv/uv_hub.h   |    4 ++++
 arch/x86/include/asm/uv/uv_mmrs.h  |   19 ++++++++++++++++++-
 arch/x86/kernel/apic/x2apic_uv_x.c |   25 +++++++++++++++++++++++--
 arch/x86/platform/uv/tlb_uv.c      |    2 +-
 arch/x86/platform/uv/uv_time.c     |    4 +++-
 5 files changed, 49 insertions(+), 5 deletions(-)

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/x86/platform/uv/tlb_uv.c b/arch/x86/platform/uv/tlb_uv.c
index a318194002b5..ba9caa808a9c 100644
--- a/arch/x86/platform/uv/tlb_uv.c
+++ b/arch/x86/platform/uv/tlb_uv.c
@@ -1455,7 +1455,7 @@ static void __init uv_init_uvhub(int uvhub, int vector)
          * the below initialization can't be in firmware because the
          * messaging IRQ will be determined by the OS
          */
-        apicid = uvhub_to_first_apicid(uvhub);
+        apicid = uvhub_to_first_apicid(uvhub) | uv_apicid_hibits;
         uv_write_global_mmr64(pnode, UVH_BAU_DATA_CONFIG,
                                       ((apicid << 32) | vector));
 }