[Xen-devel] [PATCH v2 2/2] x86/apic: simplify disconnect_bsp_APIC setup of LVT{0/1}

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

There's no need to read the current values of LVT{0/1} for the
purposes of the function, which seem to be to save the currently
selected vector: in the destination modes used (ExtINT and NMI) the
vector field is ignored and hence can be set to 0.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
 xen/arch/x86/apic.c | 15 ++-------------
 1 file changed, 2 insertions(+), 13 deletions(-)

diff --git a/xen/arch/x86/apic.c b/xen/arch/x86/apic.c
index 508b1586f2..c18314c1a3 100644
--- a/xen/arch/x86/apic.c
+++ b/xen/arch/x86/apic.c
@@ -273,23 +273,12 @@ void disconnect_bsp_APIC(int virt_wire_setup)
 
         if (!virt_wire_setup) {
             /* For LVT0 make it edge triggered, active high, external and 
enabled */
-            value = apic_read(APIC_LVT0);
-            value &= ~(APIC_MODE_MASK | APIC_SEND_PENDING |
-                       APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
-                       APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED );
-            value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
-            value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_EXTINT);
+            value = APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING | APIC_DM_EXTINT;
             apic_write(APIC_LVT0, value);
         }
 
         /* For LVT1 make it edge triggered, active high, nmi and enabled */
-        value = apic_read(APIC_LVT1);
-        value &= ~(
-            APIC_MODE_MASK | APIC_SEND_PENDING |
-            APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
-            APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED);
-        value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
-        value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_NMI);
+        value = APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING | APIC_DM_NMI;
         apic_write(APIC_LVT1, value);
     }
 }
-- 
2.25.0


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