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Re: [PATCH 07/11] xen/arm: if 1:1 direct-map domain use native addresses for GICv2



Hi,

On 23/09/2021 08:11, Penny Zheng wrote:
From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>

Today we use native addresses to map the GICv2 for Dom0 and fixed
addresses for DomUs.

This patch changes the behavior so that native addresses are used for
all domains that are 1:1 direct-map(including Dom0).

Update the accessors to use the struct vgic variables to provide the
updated addresses.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
Signed-off-by: Penny Zheng <penny.zheng@xxxxxxx>
---
  xen/arch/arm/vgic-v2.c         | 16 ++++++++++++++++
  xen/arch/arm/vgic/vgic-v2.c    | 17 +++++++++++++++++
  xen/include/asm-arm/new_vgic.h |  4 ++--
  xen/include/asm-arm/vgic.h     |  4 ++--
  4 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/xen/arch/arm/vgic-v2.c b/xen/arch/arm/vgic-v2.c
index b34ec88106..a8cf8173d0 100644
--- a/xen/arch/arm/vgic-v2.c
+++ b/xen/arch/arm/vgic-v2.c
@@ -673,6 +673,22 @@ static int vgic_v2_domain_init(struct domain *d)
          csize = vgic_v2_hw.csize;
          vbase = vgic_v2_hw.vbase;
      }
+    else if ( is_domain_direct_mapped(d) )
+    {
+        /*
+         * For non-dom0 direct_mapped guests we only map a 8kB CPU
+         * interface but we make sure it is at a location occupied by
+         * the physical GIC in the host device tree.
+         *
+         * We need to add an offset to the virtual CPU interface base
+         * address when the GIC is aliased to get a 8kB contiguous
+         * region.
+         */

So I agree that we need to differentiate between dom0 and other direct mapped domains. However, I think it would be good to explainm why given that in other places you treat dom0 and direct mapped domain the same way.

+        d->arch.vgic.dbase = vgic_v2_hw.dbase;
+        d->arch.vgic.cbase = vgic_v2_hw.cbase + vgic_v2_hw.aliased_offset;
+        csize = GUEST_GICC_SIZE;
+        vbase = vgic_v2_hw.vbase + vgic_v2_hw.aliased_offset;
+    }
      else
      {
          d->arch.vgic.dbase = GUEST_GICD_BASE;
diff --git a/xen/arch/arm/vgic/vgic-v2.c b/xen/arch/arm/vgic/vgic-v2.c
index fd452fcb5a..ce1f6e4373 100644
--- a/xen/arch/arm/vgic/vgic-v2.c
+++ b/xen/arch/arm/vgic/vgic-v2.c
@@ -280,6 +280,23 @@ int vgic_v2_map_resources(struct domain *d)
          csize = gic_v2_hw_data.csize;
          vbase = gic_v2_hw_data.vbase;
      }
+    else if ( is_domain_direct_mapped(d) )
+    {
+        d->arch.vgic.vgic_dist_base = gic_v2_hw_data.dbase;
+        /*
+         * For non-dom0 direct_mapped guests we only map a 8kB CPU
+         * interface but we make sure it is at a location occupied by
+         * the physical GIC in the host device tree.
+         *
+         * We need to add an offset to the virtual CPU interface base
+         * address when the GIC is aliased to get a 8kB contiguous
+         * region.
+         */
+        d->arch.vgic.vgic_cpu_base = gic_v2_hw_data.cbase +
+                                     gic_v2_hw_data.aliased_offset;
+        csize = GUEST_GICC_SIZE;
+        vbase = gic_v2_hw_data.vbase + gic_v2_hw_data.aliased_offset;
+    }
      else
      {
          d->arch.vgic.vgic_dist_base = GUEST_GICD_BASE;
diff --git a/xen/include/asm-arm/new_vgic.h b/xen/include/asm-arm/new_vgic.h
index 9097522b27..0d16f878eb 100644
--- a/xen/include/asm-arm/new_vgic.h
+++ b/xen/include/asm-arm/new_vgic.h
@@ -188,12 +188,12 @@ struct vgic_cpu {
static inline paddr_t vgic_cpu_base(struct vgic_dist *vgic)
  {
-    return GUEST_GICC_BASE;
+    return vgic->vgic_cpu_base;
  }
static inline paddr_t vgic_dist_base(struct vgic_dist *vgic)
  {
-    return GUEST_GICD_BASE;
+    return vgic->vgic_dist_base;
  }
static inline unsigned int vgic_rdist_nr(struct vgic_dist *vgic)
diff --git a/xen/include/asm-arm/vgic.h b/xen/include/asm-arm/vgic.h
index d5ad1f387b..92f6a2d15d 100644
--- a/xen/include/asm-arm/vgic.h
+++ b/xen/include/asm-arm/vgic.h
@@ -280,12 +280,12 @@ enum gic_sgi_mode;
static inline paddr_t vgic_cpu_base(struct vgic_dist *vgic)
  {
-    return GUEST_GICC_BASE;
+    return vgic->cbase;
  }
static inline paddr_t vgic_dist_base(struct vgic_dist *vgic)
  {
-    return GUEST_GICD_BASE;
+    return vgic->dbase;
  }
#ifdef CONFIG_GICV3 >

Cheers,

--
Julien Grall



 


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