[Xen-devel] [RFC PATCH 05/49] ARM: vGICv3: always use architected redist stride

[Andre Przywara <andre.przywara@xxxxxxxxxx>]

The redistributor-stride property in a GICv3 DT node is only there to
cover broken platforms where this value deviates from the architected one.
Since we emulate the GICv3 distributor even for Dom0, we don't need to
copy the broken behaviour. All the special handling for Dom0s using
GICv3 is just for using the hardware's memory map, which is unaffected
by the redistributor stride - it can never be smaller than the
architected two pages.
Remove the redistributor-stride property from Dom0's DT node and also
remove the code that tried to reuse the hardware value for Dom0's GICv3
emulation.

Signed-off-by: Andre Przywara <andre.przywara@xxxxxxxxxx>
---
 xen/arch/arm/gic-v3.c  |  5 -----
 xen/arch/arm/vgic-v3.c | 14 ++++++--------
 2 files changed, 6 insertions(+), 13 deletions(-)

diff --git a/xen/arch/arm/gic-v3.c b/xen/arch/arm/gic-v3.c
index 7837d93dc1..02c85e4c0c 100644
--- a/xen/arch/arm/gic-v3.c
+++ b/xen/arch/arm/gic-v3.c
@@ -1164,11 +1164,6 @@ static int gicv3_make_hwdom_dt_node(const struct domain 
*d,
     if ( res )
         return res;
 
-    res = fdt_property_cell(fdt, "redistributor-stride",
-                            d->arch.vgic.rdist_stride);
-    if ( res )
-        return res;
-
     res = fdt_property_cell(fdt, "#redistributor-regions", gicv3.rdist_count);
     if ( res )
         return res;
diff --git a/xen/arch/arm/vgic-v3.c b/xen/arch/arm/vgic-v3.c
index 12338c6b21..e45bbc6dcf 100644
--- a/xen/arch/arm/vgic-v3.c
+++ b/xen/arch/arm/vgic-v3.c
@@ -1024,10 +1024,9 @@ static struct vcpu *get_vcpu_from_rdist(struct domain *d,
     paddr_t gpa, uint32_t *offset)
 {
     struct vcpu *v;
-    uint32_t stride = d->arch.vgic.rdist_stride;
     unsigned int vcpu_id;
 
-    vcpu_id = region->first_cpu + ((gpa - region->base) / stride);
+    vcpu_id = region->first_cpu + ((gpa - region->base) / GICV3_GICR_SIZE);
     if ( unlikely(vcpu_id >= d->max_vcpus) )
         return NULL;
 
@@ -1586,7 +1585,6 @@ static int vgic_v3_vcpu_init(struct vcpu *v)
 
     /* Convenient alias */
     struct domain *d = v->domain;
-    uint32_t rdist_stride = d->arch.vgic.rdist_stride;
 
     /*
      * Find the region where the re-distributor lives. For this purpose,
@@ -1602,11 +1600,11 @@ static int vgic_v3_vcpu_init(struct vcpu *v)
 
     /* Get the base address of the redistributor */
     rdist_base = region->base;
-    rdist_base += (v->vcpu_id - region->first_cpu) * rdist_stride;
+    rdist_base += (v->vcpu_id - region->first_cpu) * GICV3_GICR_SIZE;
 
     /* Check if a valid region was found for the re-distributor */
     if ( (rdist_base < region->base) ||
-         ((rdist_base + rdist_stride) > (region->base + region->size)) )
+         ((rdist_base + GICV3_GICR_SIZE) > (region->base + region->size)) )
     {
         dprintk(XENLOG_ERR,
                 "d%u: Unable to find a re-distributor for VCPU %u\n",
@@ -1622,7 +1620,7 @@ static int vgic_v3_vcpu_init(struct vcpu *v)
      * VGIC_V3_RDIST_LAST flags.
      * Note that we are assuming max_vcpus will never change.
      */
-    last_cpu = (region->size / rdist_stride) + region->first_cpu - 1;
+    last_cpu = (region->size / GICV3_GICR_SIZE) + region->first_cpu - 1;
 
     if ( v->vcpu_id == last_cpu || (v->vcpu_id == (d->max_vcpus - 1)) )
         v->arch.vgic.flags |= VGIC_V3_RDIST_LAST;
@@ -1693,7 +1691,7 @@ static int vgic_v3_domain_init(struct domain *d)
             /* Set the first CPU handled by this region */
             d->arch.vgic.rdist_regions[i].first_cpu = first_cpu;
 
-            first_cpu += size / d->arch.vgic.rdist_stride;
+            first_cpu += size / GICV3_GICR_SIZE;
         }
 
         d->arch.vgic.intid_bits = vgic_v3_hw.intid_bits;
@@ -1705,7 +1703,7 @@ static int vgic_v3_domain_init(struct domain *d)
         d->arch.vgic.rdist_stride = GUEST_GICV3_RDIST_STRIDE;
 
         /* The first redistributor should contain enough space for all CPUs */
-        BUILD_BUG_ON((GUEST_GICV3_GICR0_SIZE / GUEST_GICV3_RDIST_STRIDE) < 
MAX_VIRT_CPUS);
+        BUILD_BUG_ON((GUEST_GICV3_GICR0_SIZE / GICV3_GICR_SIZE) < 
MAX_VIRT_CPUS);
         d->arch.vgic.rdist_regions[0].base = GUEST_GICV3_GICR0_BASE;
         d->arch.vgic.rdist_regions[0].size = GUEST_GICV3_GICR0_SIZE;
         d->arch.vgic.rdist_regions[0].first_cpu = 0;
-- 
2.14.1


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