The stride may not be set if the hardware GIC is using the default
layout. It happens on the Foundation model.
On GICv3, the default stride is 2 * 64K. Therefore it's possible to avoid
checking at every redistributor MMIO access if the stride is not set.
Because domU uses a static stride configuration this only happens for
dom0, so we can move this code in gicv_v3_init. Take the opportunity to move
the stride setting a bit earlier because the loop to set regions will require
the stride.
Also, use 2 * 64K rather than 128K and explain the reason.
Signed-off-by: Julien Grall <julien.gr...@linaro.org>
---
I wasn't not sure where to move this code. I find very confusion the
splitting between vgic and gicv. Maybe we should introduce a
hwdom_gicv_init and giccc_map callbacks. Then move most of the
initialization in the vgic one.
Changes in v3:
- Fix typoes and update commit message
- Forgot to remove the check on the stride the rdist write
Changes in v2:
- Patch added
---
xen/arch/arm/gic-v3.c | 11 ++++++++++-
xen/arch/arm/vgic-v3.c | 12 ++----------
2 files changed, 12 insertions(+), 11 deletions(-)
diff --git a/xen/arch/arm/gic-v3.c b/xen/arch/arm/gic-v3.c
index 47452ca..7b33ff7 100644
--- a/xen/arch/arm/gic-v3.c
+++ b/xen/arch/arm/gic-v3.c
@@ -897,12 +897,21 @@ static int gicv_v3_init(struct domain *d)
{
d->arch.vgic.dbase = gicv3.dbase;
d->arch.vgic.dbase_size = gicv3.dbase_size;
+
+ d->arch.vgic.rdist_stride = gicv3.rdist_stride;
+ /*
+ * If the stride is not set, the default stride for GICv3 is 2 * 64K:
+ * - first 64k page for Control and Physical LPIs
+ * - second 64k page for Control and Generation of SGIs
+ */
+ if ( !d->arch.vgic.rdist_stride )
+ d->arch.vgic.rdist_stride = 2 * SZ_64K;
+
for ( i = 0; i < gicv3.rdist_count; i++ )
{
d->arch.vgic.rbase[i] = gicv3.rdist_regions[i].base;
d->arch.vgic.rbase_size[i] = gicv3.rdist_regions[i].size;
}
- d->arch.vgic.rdist_stride = gicv3.rdist_stride;
d->arch.vgic.rdist_count = gicv3.rdist_count;
}
else
diff --git a/xen/arch/arm/vgic-v3.c b/xen/arch/arm/vgic-v3.c
index 2c14717..c5a743a 100644
--- a/xen/arch/arm/vgic-v3.c
+++ b/xen/arch/arm/vgic-v3.c
@@ -625,11 +625,7 @@ static int vgic_v3_rdistr_mmio_read(struct vcpu *v,
mmio_info_t *info)
perfc_incr(vgicr_reads);
- if ( v->domain->arch.vgic.rdist_stride != 0 )
- offset = info->gpa & (v->domain->arch.vgic.rdist_stride - 1);
- else
- /* If stride is not set. Default 128K */
- offset = info->gpa & (SZ_128K - 1);
+ offset = info->gpa & (v->domain->arch.vgic.rdist_stride - 1);
if ( offset < SZ_64K )
return __vgic_v3_rdistr_rd_mmio_read(v, info, offset);
@@ -649,11 +645,7 @@ static int vgic_v3_rdistr_mmio_write(struct vcpu *v,
mmio_info_t *info)
perfc_incr(vgicr_writes);
- if ( v->domain->arch.vgic.rdist_stride != 0 )
- offset = info->gpa & (v->domain->arch.vgic.rdist_stride - 1);
- else
- /* If stride is not set. Default 128K */
- offset = info->gpa & (SZ_128K - 1);
+ offset = info->gpa & (v->domain->arch.vgic.rdist_stride - 1);
if ( offset < SZ_64K )
return __vgic_v3_rdistr_rd_mmio_write(v, info, offset);
--
2.1.4
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