[Xen-devel] [RFC 16/16] gic: vgic: align frequently accessed data by cache line size

[Andrii Anisov <andrii.anisov@xxxxxxxxx>]

From: Andrii Anisov <andrii_anisov@xxxxxxxx>

Cache line size assumed 64 byte as for H3. Align the `struct
pending_irq` and allocate lrs shadow aligned to cache line size.

Signed-off-by: Andrii Anisov <andrii_anisov@xxxxxxxx>
---
 xen/arch/arm/domain.c        | 4 ++++
 xen/arch/arm/vgic.c          | 9 +++++++++
 xen/include/asm-arm/config.h | 2 +-
 xen/include/asm-arm/gic.h    | 2 +-
 xen/include/asm-arm/vgic.h   | 2 +-
 5 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 8e886b7..8bcb667 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -558,6 +558,10 @@ int arch_vcpu_create(struct vcpu *v)
     v->arch.saved_context.sp = (register_t)v->arch.cpu_info;
     v->arch.saved_context.pc = (register_t)continue_new_vcpu;
 
+    v->arch.gic.v2.lr = xzalloc_bytes(sizeof(uint32_t) * gic_number_lines());
+    if ( v->arch.gic.v2.lr == NULL )
+        return -ENOMEM;
+
     /* Idle VCPUs don't need the rest of this setup */
     if ( is_idle_vcpu(v) )
         return rc;
diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
index 7691310..bedfb99 100644
--- a/xen/arch/arm/vgic.c
+++ b/xen/arch/arm/vgic.c
@@ -166,6 +166,15 @@ int domain_vgic_init(struct domain *d, unsigned int 
nr_spis)
 
     d->arch.vgic.pending_irqs =
         xzalloc_array(struct pending_irq, d->arch.vgic.nr_spis);
+
+    if ( sizeof(struct pending_irq) != dcache_line_bytes )
+    {
+        printk ("sizeof(struct pending_irq) = %lu  is not equal to cacheline"
+                "size %lu. Is it expected?\n", sizeof(struct pending_irq),
+                dcache_line_bytes);
+        WARN();
+    }
+
     if ( d->arch.vgic.pending_irqs == NULL )
         return -ENOMEM;
 
diff --git a/xen/include/asm-arm/config.h b/xen/include/asm-arm/config.h
index bc89e84..4f3669f 100644
--- a/xen/include/asm-arm/config.h
+++ b/xen/include/asm-arm/config.h
@@ -28,7 +28,7 @@
 
 #define CONFIG_ARM 1
 
-#define CONFIG_ARM_L1_CACHE_SHIFT 7 /* XXX */
+#define CONFIG_ARM_L1_CACHE_SHIFT 6 /* XXX */
 
 #define CONFIG_SMP 1
 
diff --git a/xen/include/asm-arm/gic.h b/xen/include/asm-arm/gic.h
index add2566..fe44d3a 100644
--- a/xen/include/asm-arm/gic.h
+++ b/xen/include/asm-arm/gic.h
@@ -186,7 +186,7 @@ struct gic_v2 {
     uint32_t hcr;
     uint32_t vmcr;
     uint32_t apr;
-    uint32_t lr[64];
+    uint32_t *lr;
     uint64_t lr_update_mask;
 };
 
diff --git a/xen/include/asm-arm/vgic.h b/xen/include/asm-arm/vgic.h
index a27a1a9..d4ec96f 100644
--- a/xen/include/asm-arm/vgic.h
+++ b/xen/include/asm-arm/vgic.h
@@ -99,7 +99,7 @@ struct pending_irq
      * TODO: when implementing irq migration, taking only the current
      * vgic lock is not going to be enough. */
     struct list_head lr_queue;
-};
+}__cacheline_aligned;
 
 #define NR_INTERRUPT_PER_RANK   32
 #define INTERRUPT_RANK_MASK (NR_INTERRUPT_PER_RANK - 1)
-- 
2.7.4


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