[Xen-devel] [RFC PATCH] arm64: vgic-v3: Add ITS doorbell region in Dom0 stage-2

[mjaggi@xxxxxxxxxxxxxxxxxx]

From: Manish Jaggi <mjaggi@xxxxxxxxxxxxxxxxxx>

This patch introduces a function vgic_map_translation_space for mapping
ITS 64K translater space for doorbells in dom0 stage-2.
It is required as dom0 PCI devices behined SMMU  wont be able to write MSIs.

This function is called from vgic_v3_its_init_domain only for hardware domain. 

This patch is also required for testing 
[RFC 00/11] acpi: arm: IORT Support for Xen [1] 
+ [2]  [RFC v4 0/8] SMMUv3 driver
 
[1] https://lists.xenproject.org/archives/html/xen-devel/2018-01/msg00007.html
[2] https://lists.xen.org/archives/html/xen-devel/2017-12/msg01294.html

Signed-off-by: Manish Jaggi <manish.jaggi@xxxxxxxxxx>
---
 xen/arch/arm/vgic-v3-its.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/xen/arch/arm/vgic-v3-its.c b/xen/arch/arm/vgic-v3-its.c
index 72a5c70656..a8f8079149 100644
--- a/xen/arch/arm/vgic-v3-its.c
+++ b/xen/arch/arm/vgic-v3-its.c
@@ -1511,6 +1511,30 @@ unsigned int vgic_v3_its_count(const struct domain *d)
     return ret;
 }
 
+static int vgic_map_translation_space(struct domain *d, paddr_t guest_addr)
+{
+    u64 addr, size;
+    int ret;
+    addr = guest_addr + SZ_64K;
+    size = SZ_64K;
+
+    ret = map_mmio_regions(d,
+                           paddr_to_pfn(addr & PAGE_MASK),
+                           DIV_ROUND_UP(size, PAGE_SIZE),
+                           paddr_to_pfn(addr & PAGE_MASK));
+
+    if ( ret )
+    {
+        printk(XENLOG_ERR "Unable to map to dom%d access to"
+               " 0x%"PRIx64" - 0x%"PRIx64"\n",
+               d->domain_id,
+               addr & PAGE_MASK, PAGE_ALIGN(addr + size) - 1);
+    }
+
+    return ret;
+
+}
+
 /*
  * For a hardware domain, this will iterate over the host ITSes
  * and map one virtual ITS per host ITS at the same address.
@@ -1541,6 +1565,8 @@ int vgic_v3_its_init_domain(struct domain *d)
                 return ret;
             else
                 d->arch.vgic.has_its = true;
+            
+            vgic_map_translation_space(d, hw_its->addr);
         }
     }
 
-- 
2.14.1


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