xen/arm: calculate vgic irq rank based on register size

vGIC irq rank was computed assuming the register offset is byte
size.Use the HSR abort address size in calculating register size.

So, with this patch following are achieved
   (1) In the code 'dabt.size != number' this number is always
       BYTE/HALF_WORD/WORD/DOUBLE defined by HSR register.
       Instead of checking for hard coded values use HSR abort
       address size values.
   (2) The vgic_rank_offset also depends on register size to
       compute the rank offset. Though there is no direct relation
       between rank offset computation and HSR dabt.size the same
       values are used to calculate irq rank.

This make vgic_rank_offset generic as it takes register
size as parameter to calculate irq rank instead of hard coding to
value 2 in previous patches

Also, output of REG_RANK_INDEX macro is modulo by 32 to make
sure register index is always within irq rank

Signed-off-by: Vijaya Kumar K <Vijaya.Kumar@caviumnetworks.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
index da807bdc7a0bd08e0288f5e235dc5e36ac0b9d48..48551bf56d74d08c9a6b2e04b8c0a289c6825e3a 100644 (file)
--- a/xen/arch/arm/vgic.c
+++ b/xen/arch/arm/vgic.c
@@ -40,9 +40,10 @@ static int vgic_distr_mmio_write(struct vcpu *v, mmio_info_t *info);
  * Returns rank corresponding to a GICD_<FOO><n> register for
  * GICD_<FOO> with <b>-bits-per-interrupt.
  */
-static struct vgic_irq_rank *vgic_rank_offset(struct vcpu *v, int b, int n)
+static struct vgic_irq_rank *vgic_rank_offset(struct vcpu *v, int b, int n,
+                                              int s)
 {
-    int rank = REG_RANK_NR(b, (n >> 2));
+    int rank = REG_RANK_NR(b, (n >> s));
 
     if ( rank == 0 )
         return v->arch.vgic.private_irqs;
@@ -54,7 +55,7 @@ static struct vgic_irq_rank *vgic_rank_offset(struct vcpu *v, int b, int n)
 
 static struct vgic_irq_rank *vgic_rank_irq(struct vcpu *v, unsigned int irq)
 {
-    return vgic_rank_offset(v, 8, irq);
+    return vgic_rank_offset(v, 8, irq, DABT_WORD);
 }
 
 static const struct mmio_handler_ops vgic_distr_mmio_handler = {
@@ -161,13 +162,13 @@ static int vgic_distr_mmio_read(struct vcpu *v, mmio_info_t *info)
     switch ( gicd_reg )
     {
     case GICD_CTLR:
-        if ( dabt.size != 2 ) goto bad_width;
+        if ( dabt.size != DABT_WORD ) goto bad_width;
         vgic_lock(v);
         *r = v->domain->arch.vgic.ctlr;
         vgic_unlock(v);
         return 1;
     case GICD_TYPER:
-        if ( dabt.size != 2 ) goto bad_width;
+        if ( dabt.size != DABT_WORD ) goto bad_width;
         /* No secure world support for guests. */
         vgic_lock(v);
         *r = ( (v->domain->max_vcpus<<5) & GICD_TYPE_CPUS )
@@ -175,7 +176,7 @@ static int vgic_distr_mmio_read(struct vcpu *v, mmio_info_t *info)
         vgic_unlock(v);
         return 1;
     case GICD_IIDR:
-        if ( dabt.size != 2 ) goto bad_width;
+        if ( dabt.size != DABT_WORD ) goto bad_width;
         /*
          * XXX Do we need a JEP106 manufacturer ID?
          * Just use the physical h/w value for now
@@ -192,8 +193,8 @@ static int vgic_distr_mmio_read(struct vcpu *v, mmio_info_t *info)
         goto read_as_zero;
 
     case GICD_ISENABLER ... GICD_ISENABLERN:
-        if ( dabt.size != 2 ) goto bad_width;
-        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ISENABLER);
+        if ( dabt.size != DABT_WORD ) goto bad_width;
+        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ISENABLER, DABT_WORD);
         if ( rank == NULL) goto read_as_zero;
         vgic_lock_rank(v, rank);
         *r = rank->ienable;
@@ -201,8 +202,8 @@ static int vgic_distr_mmio_read(struct vcpu *v, mmio_info_t *info)
         return 1;
 
     case GICD_ICENABLER ... GICD_ICENABLERN:
-        if ( dabt.size != 2 ) goto bad_width;
-        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ICENABLER);
+        if ( dabt.size != DABT_WORD ) goto bad_width;
+        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ICENABLER, DABT_WORD);
         if ( rank == NULL) goto read_as_zero;
         vgic_lock_rank(v, rank);
         *r = rank->ienable;
@@ -210,8 +211,8 @@ static int vgic_distr_mmio_read(struct vcpu *v, mmio_info_t *info)
         return 1;
 
     case GICD_ISPENDR ... GICD_ISPENDRN:
-        if ( dabt.size != 0 && dabt.size != 2 ) goto bad_width;
-        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ISPENDR);
+        if ( dabt.size != DABT_BYTE && dabt.size != DABT_WORD ) goto bad_width;
+        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ISPENDR, DABT_WORD);
         if ( rank == NULL) goto read_as_zero;
         vgic_lock_rank(v, rank);
         *r = vgic_byte_read(rank->ipend, dabt.sign, offset);
@@ -219,8 +220,8 @@ static int vgic_distr_mmio_read(struct vcpu *v, mmio_info_t *info)
         return 1;
 
     case GICD_ICPENDR ... GICD_ICPENDRN:
-        if ( dabt.size != 0 && dabt.size != 2 ) goto bad_width;
-        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ICPENDR);
+        if ( dabt.size != DABT_BYTE && dabt.size != DABT_WORD ) goto bad_width;
+        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ICPENDR, DABT_WORD);
         if ( rank == NULL) goto read_as_zero;
         vgic_lock_rank(v, rank);
         *r = vgic_byte_read(rank->ipend, dabt.sign, offset);
@@ -228,8 +229,8 @@ static int vgic_distr_mmio_read(struct vcpu *v, mmio_info_t *info)
         return 1;
 
     case GICD_ISACTIVER ... GICD_ISACTIVERN:
-        if ( dabt.size != 2 ) goto bad_width;
-        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ISACTIVER);
+        if ( dabt.size != DABT_WORD ) goto bad_width;
+        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ISACTIVER, DABT_WORD);
         if ( rank == NULL) goto read_as_zero;
         vgic_lock_rank(v, rank);
         *r = rank->iactive;
@@ -237,8 +238,8 @@ static int vgic_distr_mmio_read(struct vcpu *v, mmio_info_t *info)
         return 1;
 
     case GICD_ICACTIVER ... GICD_ICACTIVERN:
-        if ( dabt.size != 2 ) goto bad_width;
-        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ICACTIVER);
+        if ( dabt.size != DABT_WORD ) goto bad_width;
+        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ICACTIVER, DABT_WORD);
         if ( rank == NULL) goto read_as_zero;
         vgic_lock_rank(v, rank);
         *r = rank->iactive;
@@ -246,35 +247,37 @@ static int vgic_distr_mmio_read(struct vcpu *v, mmio_info_t *info)
         return 1;
 
     case GICD_ITARGETSR ... GICD_ITARGETSRN:
-        if ( dabt.size != 0 && dabt.size != 2 ) goto bad_width;
-        rank = vgic_rank_offset(v, 8, gicd_reg - GICD_ITARGETSR);
+        if ( dabt.size != DABT_BYTE && dabt.size != DABT_WORD ) goto bad_width;
+        rank = vgic_rank_offset(v, 8, gicd_reg - GICD_ITARGETSR, DABT_WORD);
         if ( rank == NULL) goto read_as_zero;
 
         vgic_lock_rank(v, rank);
-        *r = rank->itargets[REG_RANK_INDEX(8, gicd_reg - GICD_ITARGETSR)];
-        if ( dabt.size == 0 )
+        *r = rank->itargets[REG_RANK_INDEX(8, gicd_reg - GICD_ITARGETSR,
+                                           DABT_WORD)];
+        if ( dabt.size == DABT_BYTE )
             *r = vgic_byte_read(*r, dabt.sign, offset);
         vgic_unlock_rank(v, rank);
         return 1;
 
     case GICD_IPRIORITYR ... GICD_IPRIORITYRN:
-        if ( dabt.size != 0 && dabt.size != 2 ) goto bad_width;
-        rank = vgic_rank_offset(v, 8, gicd_reg - GICD_IPRIORITYR);
+        if ( dabt.size != 0 && dabt.size != DABT_WORD ) goto bad_width;
+        rank = vgic_rank_offset(v, 8, gicd_reg - GICD_IPRIORITYR, DABT_WORD);
         if ( rank == NULL) goto read_as_zero;
 
         vgic_lock_rank(v, rank);
-        *r = rank->ipriority[REG_RANK_INDEX(8, gicd_reg - GICD_IPRIORITYR)];
-        if ( dabt.size == 0 )
+        *r = rank->ipriority[REG_RANK_INDEX(8, gicd_reg - GICD_IPRIORITYR,
+                                            DABT_WORD)];
+        if ( dabt.size == DABT_BYTE )
             *r = vgic_byte_read(*r, dabt.sign, offset);
         vgic_unlock_rank(v, rank);
         return 1;
 
     case GICD_ICFGR ... GICD_ICFGRN:
-        if ( dabt.size != 2 ) goto bad_width;
-        rank = vgic_rank_offset(v, 2, gicd_reg - GICD_ICFGR);
+        if ( dabt.size != DABT_WORD ) goto bad_width;
+        rank = vgic_rank_offset(v, 2, gicd_reg - GICD_ICFGR, DABT_WORD);
         if ( rank == NULL) goto read_as_zero;
         vgic_lock_rank(v, rank);
-        *r = rank->icfg[REG_RANK_INDEX(2, gicd_reg - GICD_ICFGR)];
+        *r = rank->icfg[REG_RANK_INDEX(2, gicd_reg - GICD_ICFGR, DABT_WORD)];
         vgic_unlock_rank(v, rank);
         return 1;
 
@@ -283,14 +286,14 @@ static int vgic_distr_mmio_read(struct vcpu *v, mmio_info_t *info)
         goto read_as_zero;
 
     case GICD_SGIR:
-        if ( dabt.size != 2 ) goto bad_width;
+        if ( dabt.size != DABT_WORD ) goto bad_width;
         /* Write only -- read unknown */
         *r = 0xdeadbeef;
         return 1;
 
     case GICD_CPENDSGIR ... GICD_CPENDSGIRN:
-        if ( dabt.size != 0 && dabt.size != 2 ) goto bad_width;
-        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_CPENDSGIR);
+        if ( dabt.size != DABT_BYTE && dabt.size != DABT_WORD ) goto bad_width;
+        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_CPENDSGIR, DABT_WORD);
         if ( rank == NULL) goto read_as_zero;
         vgic_lock_rank(v, rank);
         *r = vgic_byte_read(rank->pendsgi, dabt.sign, offset);
@@ -298,8 +301,8 @@ static int vgic_distr_mmio_read(struct vcpu *v, mmio_info_t *info)
         return 1;
 
     case GICD_SPENDSGIR ... GICD_SPENDSGIRN:
-        if ( dabt.size != 0 && dabt.size != 2 ) goto bad_width;
-        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_SPENDSGIR);
+        if ( dabt.size != DABT_BYTE && dabt.size != DABT_WORD ) goto bad_width;
+        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_SPENDSGIR, DABT_WORD);
         if ( rank == NULL) goto read_as_zero;
         vgic_lock_rank(v, rank);
         *r = vgic_byte_read(rank->pendsgi, dabt.sign, offset);
@@ -311,7 +314,7 @@ static int vgic_distr_mmio_read(struct vcpu *v, mmio_info_t *info)
         goto read_as_zero;
 
     case GICD_ICPIDR2:
-        if ( dabt.size != 2 ) goto bad_width;
+        if ( dabt.size != DABT_WORD ) goto bad_width;
         printk("vGICD: unhandled read from ICPIDR2\n");
         return 0;
 
@@ -341,7 +344,7 @@ bad_width:
     return 0;
 
 read_as_zero:
-    if ( dabt.size != 2 ) goto bad_width;
+    if ( dabt.size != DABT_WORD ) goto bad_width;
     *r = 0;
     return 1;
 }
@@ -468,7 +471,7 @@ static int vgic_distr_mmio_write(struct vcpu *v, mmio_info_t *info)
     switch ( gicd_reg )
     {
     case GICD_CTLR:
-        if ( dabt.size != 2 ) goto bad_width;
+        if ( dabt.size != DABT_WORD ) goto bad_width;
         /* Ignore all but the enable bit */
         v->domain->arch.vgic.ctlr = (*r) & GICD_CTL_ENABLE;
         return 1;
@@ -487,42 +490,44 @@ static int vgic_distr_mmio_write(struct vcpu *v, mmio_info_t *info)
         goto write_ignore;
 
     case GICD_ISENABLER ... GICD_ISENABLERN:
-        if ( dabt.size != 2 ) goto bad_width;
-        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ISENABLER);
+        if ( dabt.size != DABT_WORD ) goto bad_width;
+        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ISENABLER, DABT_WORD);
         if ( rank == NULL) goto write_ignore;
         vgic_lock_rank(v, rank);
         tr = rank->ienable;
         rank->ienable |= *r;
         vgic_unlock_rank(v, rank);
-        vgic_enable_irqs(v, (*r) & (~tr), (gicd_reg - GICD_ISENABLER) >> 2);
+        vgic_enable_irqs(v, (*r) & (~tr),
+                         (gicd_reg - GICD_ISENABLER) >> DABT_WORD);
         return 1;
 
     case GICD_ICENABLER ... GICD_ICENABLERN:
-        if ( dabt.size != 2 ) goto bad_width;
-        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ICENABLER);
+        if ( dabt.size != DABT_WORD ) goto bad_width;
+        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ICENABLER, DABT_WORD);
         if ( rank == NULL) goto write_ignore;
         vgic_lock_rank(v, rank);
         tr = rank->ienable;
         rank->ienable &= ~*r;
         vgic_unlock_rank(v, rank);
-        vgic_disable_irqs(v, (*r) & tr, (gicd_reg - GICD_ICENABLER) >> 2);
+        vgic_disable_irqs(v, (*r) & tr,
+                          (gicd_reg - GICD_ICENABLER) >> DABT_WORD);
         return 1;
 
     case GICD_ISPENDR ... GICD_ISPENDRN:
-        if ( dabt.size != 0 && dabt.size != 2 ) goto bad_width;
+        if ( dabt.size != DABT_BYTE && dabt.size != DABT_WORD ) goto bad_width;
         printk("vGICD: unhandled %s write %#"PRIregister" to ISPENDR%d\n",
                dabt.size ? "word" : "byte", *r, gicd_reg - GICD_ISPENDR);
         return 0;
 
     case GICD_ICPENDR ... GICD_ICPENDRN:
-        if ( dabt.size != 0 && dabt.size != 2 ) goto bad_width;
+        if ( dabt.size != DABT_BYTE && dabt.size != DABT_WORD ) goto bad_width;
         printk("vGICD: unhandled %s write %#"PRIregister" to ICPENDR%d\n",
                dabt.size ? "word" : "byte", *r, gicd_reg - GICD_ICPENDR);
         return 0;
 
     case GICD_ISACTIVER ... GICD_ISACTIVERN:
-        if ( dabt.size != 2 ) goto bad_width;
-        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ISACTIVER);
+        if ( dabt.size != DABT_WORD ) goto bad_width;
+        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ISACTIVER, DABT_WORD);
         if ( rank == NULL) goto write_ignore;
         vgic_lock_rank(v, rank);
         rank->iactive &= ~*r;
@@ -530,8 +535,8 @@ static int vgic_distr_mmio_write(struct vcpu *v, mmio_info_t *info)
         return 1;
 
     case GICD_ICACTIVER ... GICD_ICACTIVERN:
-        if ( dabt.size != 2 ) goto bad_width;
-        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ICACTIVER);
+        if ( dabt.size != DABT_WORD ) goto bad_width;
+        rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ICACTIVER, DABT_WORD);
         if ( rank == NULL) goto write_ignore;
         vgic_lock_rank(v, rank);
         rank->iactive &= ~*r;
@@ -543,30 +548,32 @@ static int vgic_distr_mmio_write(struct vcpu *v, mmio_info_t *info)
         goto write_ignore;
 
     case GICD_ITARGETSR + 8 ... GICD_ITARGETSRN:
-        if ( dabt.size != 0 && dabt.size != 2 ) goto bad_width;
-        rank = vgic_rank_offset(v, 8, gicd_reg - GICD_ITARGETSR);
+        if ( dabt.size != DABT_BYTE && dabt.size != DABT_WORD ) goto bad_width;
+        rank = vgic_rank_offset(v, 8, gicd_reg - GICD_ITARGETSR, DABT_WORD);
         if ( rank == NULL) goto write_ignore;
         vgic_lock_rank(v, rank);
-        if ( dabt.size == 2 )
-            rank->itargets[REG_RANK_INDEX(8, gicd_reg - GICD_ITARGETSR)] = *r;
+        if ( dabt.size == DABT_WORD )
+            rank->itargets[REG_RANK_INDEX(8, gicd_reg - GICD_ITARGETSR,
+                                          DABT_WORD)] = *r;
         else
         {
-            tr = REG_RANK_INDEX(8, gicd_reg - GICD_ITARGETSR);
+            tr = REG_RANK_INDEX(8, gicd_reg - GICD_ITARGETSR, DABT_WORD);
             vgic_byte_write(&rank->itargets[tr], *r, offset);
         }
         vgic_unlock_rank(v, rank);
         return 1;
 
     case GICD_IPRIORITYR ... GICD_IPRIORITYRN:
-        if ( dabt.size != 0 && dabt.size != 2 ) goto bad_width;
-        rank = vgic_rank_offset(v, 8, gicd_reg - GICD_IPRIORITYR);
+        if ( dabt.size != DABT_BYTE && dabt.size != DABT_WORD ) goto bad_width;
+        rank = vgic_rank_offset(v, 8, gicd_reg - GICD_IPRIORITYR, DABT_WORD);
         if ( rank == NULL) goto write_ignore;
         vgic_lock_rank(v, rank);
-        if ( dabt.size == 2 )
-            rank->ipriority[REG_RANK_INDEX(8, gicd_reg - GICD_IPRIORITYR)] = *r;
+        if ( dabt.size == DABT_WORD )
+            rank->ipriority[REG_RANK_INDEX(8, gicd_reg - GICD_IPRIORITYR,
+                                           DABT_WORD)] = *r;
         else
         {
-            tr = REG_RANK_INDEX(8, gicd_reg - GICD_IPRIORITYR);
+            tr = REG_RANK_INDEX(8, gicd_reg - GICD_IPRIORITYR, DABT_WORD);
             vgic_byte_write(&rank->ipriority[tr], *r, offset);
         }
         vgic_unlock_rank(v, rank);
@@ -578,11 +585,11 @@ static int vgic_distr_mmio_write(struct vcpu *v, mmio_info_t *info)
         /* It is implementation defined if these are writeable. We chose not */
         goto write_ignore;
     case GICD_ICFGR + 2 ... GICD_ICFGRN: /* SPIs */
-        if ( dabt.size != 2 ) goto bad_width;
-        rank = vgic_rank_offset(v, 2, gicd_reg - GICD_ICFGR);
+        if ( dabt.size != DABT_WORD ) goto bad_width;
+        rank = vgic_rank_offset(v, 2, gicd_reg - GICD_ICFGR, DABT_WORD);
         if ( rank == NULL) goto write_ignore;
         vgic_lock_rank(v, rank);
-        rank->icfg[REG_RANK_INDEX(2, gicd_reg - GICD_ICFGR)] = *r;
+        rank->icfg[REG_RANK_INDEX(2, gicd_reg - GICD_ICFGR, DABT_WORD)] = *r;
         vgic_unlock_rank(v, rank);
         return 1;
 
@@ -596,13 +603,13 @@ static int vgic_distr_mmio_write(struct vcpu *v, mmio_info_t *info)
         return vgic_to_sgi(v, *r);
 
     case GICD_CPENDSGIR ... GICD_CPENDSGIRN:
-        if ( dabt.size != 0 && dabt.size != 2 ) goto bad_width;
+        if ( dabt.size != DABT_BYTE && dabt.size != DABT_WORD ) goto bad_width;
         printk("vGICD: unhandled %s write %#"PRIregister" to ICPENDSGIR%d\n",
                dabt.size ? "word" : "byte", *r, gicd_reg - GICD_CPENDSGIR);
         return 0;
 
     case GICD_SPENDSGIR ... GICD_SPENDSGIRN:
-        if ( dabt.size != 0 && dabt.size != 2 ) goto bad_width;
+        if ( dabt.size != DABT_BYTE && dabt.size != DABT_WORD ) goto bad_width;
         printk("vGICD: unhandled %s write %#"PRIregister" to ISPENDSGIR%d\n",
                dabt.size ? "word" : "byte", *r, gicd_reg - GICD_SPENDSGIR);
         return 0;
@@ -641,7 +648,7 @@ bad_width:
     return 0;
 
 write_ignore:
-    if ( dabt.size != 2 ) goto bad_width;
+    if ( dabt.size != DABT_WORD ) goto bad_width;
     return 1;
 }
 
@@ -693,7 +700,7 @@ void vgic_vcpu_inject_irq(struct vcpu *v, unsigned int irq)
         return;
     }
 
-    priority = vgic_byte_read(rank->ipriority[REG_RANK_INDEX(8, irq)], 0, irq & 0x3);
+    priority = vgic_byte_read(rank->ipriority[REG_RANK_INDEX(8, irq, DABT_WORD)], 0, irq & 0x3);
 
     n->irq = irq;
     set_bit(GIC_IRQ_GUEST_QUEUED, &n->status);

diff --git a/xen/include/asm-arm/processor.h b/xen/include/asm-arm/processor.h
index 3be86f18c3b8f2c42f3871aa455ccdb334f96f8c..bdfff4e95de22a4a3b6af31b69874d41ecdbc669 100644 (file)
--- a/xen/include/asm-arm/processor.h
+++ b/xen/include/asm-arm/processor.h
@@ -251,6 +251,14 @@ extern struct cpuinfo_arm cpu_data[];
 extern u32 __cpu_logical_map[];
 #define cpu_logical_map(cpu) __cpu_logical_map[cpu]
 
+/* HSR data abort size definition */
+enum dabt_size {
+    DABT_BYTE        = 0,
+    DABT_HALF_WORD   = 1,
+    DABT_WORD        = 2,
+    DABT_DOUBLE_WORD = 3,
+};
+
 union hsr {
     uint32_t bits;
     struct {

diff --git a/xen/include/asm-arm/vgic.h b/xen/include/asm-arm/vgic.h
index 003c3e912082b5202033b4575527cd13b5293ee5..7c71d1620b04b86df2a6a1e292cf34620c1b9c27 100644 (file)
--- a/xen/include/asm-arm/vgic.h
+++ b/xen/include/asm-arm/vgic.h
@@ -134,10 +134,10 @@ static inline void vgic_byte_write(uint32_t *reg, uint32_t var, int offset)
 }
 
 /*
- * Offset of GICD_<FOO><n> with its rank, for GICD_<FOO> with
+ * Offset of GICD_<FOO><n> with its rank, for GICD_<FOO> size <s> with
  * <b>-bits-per-interrupt.
  */
-#define REG_RANK_INDEX(b, n) (((n) >> 2) & ((b)-1))
+#define REG_RANK_INDEX(b, n, s) ((((n) >> s) & ((b)-1)) % 32)
 
 extern int domain_vgic_init(struct domain *d);
 extern void domain_vgic_free(struct domain *d);