[Xen-devel] [PATCH 04/57] ARM: GICv3: simplify GICv3 redistributor stride handling

[Andre Przywara <andre.przywara@xxxxxxxxxx>]

Instead of hard coding the architected redistributor stride into the
code, lets use a clear #define to the two values for GICv3 and GICv4 and
clarify the algorithm to determine the needed stride value.

Signed-off-by: Andre Przywara <andre.przywara@xxxxxxxxxx>
---
Changelog RFC ... v1:
- no changes

 xen/arch/arm/gic-v3.c             | 18 ++++++++++--------
 xen/include/asm-arm/gic_v3_defs.h |  5 +++++
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/xen/arch/arm/gic-v3.c b/xen/arch/arm/gic-v3.c
index b1f8a86409..be1787b39a 100644
--- a/xen/arch/arm/gic-v3.c
+++ b/xen/arch/arm/gic-v3.c
@@ -690,6 +690,15 @@ static int __init gicv3_populate_rdist(void)
         do {
             typer = readq_relaxed(ptr + GICR_TYPER);
 
+            /* Set the architectural redist size if not overridden by DT. */
+            if ( !gicv3.rdist_stride )
+            {
+                if ( typer & GICR_TYPER_VLPIS )
+                    gicv3.rdist_stride = GICV4_GICR_SIZE;
+                else
+                    gicv3.rdist_stride = GICV3_GICR_SIZE;
+            }
+
             if ( (typer >> 32) == aff )
             {
                 this_cpu(rbase) = ptr;
@@ -732,14 +741,7 @@ static int __init gicv3_populate_rdist(void)
             if ( gicv3.rdist_regions[i].single_rdist )
                 break;
 
-            if ( gicv3.rdist_stride )
-                ptr += gicv3.rdist_stride;
-            else
-            {
-                ptr += SZ_64K * 2; /* Skip RD_base + SGI_base */
-                if ( typer & GICR_TYPER_VLPIS )
-                    ptr += SZ_64K * 2; /* Skip VLPI_base + reserved page */
-            }
+            ptr += gicv3.rdist_stride;
 
         } while ( !(typer & GICR_TYPER_LAST) );
     }
diff --git a/xen/include/asm-arm/gic_v3_defs.h 
b/xen/include/asm-arm/gic_v3_defs.h
index 65c9dc47cf..412e41afed 100644
--- a/xen/include/asm-arm/gic_v3_defs.h
+++ b/xen/include/asm-arm/gic_v3_defs.h
@@ -18,6 +18,8 @@
 #ifndef __ASM_ARM_GIC_V3_DEFS_H__
 #define __ASM_ARM_GIC_V3_DEFS_H__
 
+#include <xen/sizes.h>
+
 /*
  * Additional registers defined in GIC v3.
  * Common GICD registers are defined in gic.h
@@ -68,6 +70,9 @@
 #define GICV3_GICD_IIDR_VAL          0x34c
 #define GICV3_GICR_IIDR_VAL          GICV3_GICD_IIDR_VAL
 
+#define GICV3_GICR_SIZE              (2 * SZ_64K)
+#define GICV4_GICR_SIZE              (4 * SZ_64K)
+
 #define GICR_CTLR                    (0x0000)
 #define GICR_IIDR                    (0x0004)
 #define GICR_TYPER                   (0x0008)
-- 
2.14.1


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