[PATCH] xen/arm: p2m: Populate pages for GICv2 mapping in arch_domain_create()

[Henry Wang]

Hardware using GICv2 needs to create a P2M mapping of 8KB GICv2 area
when the domain is created. Considering the worst case of page tables
and keep a buffer, populate 16 pages as the default value to the P2M
pages pool in arch_domain_create() at the domain creation stage to
satisfy the GICv2 requirement.

Fixes: cbea5a1149ca ("xen/arm: Allocate and free P2M pages from the P2M pool")
Suggested-by: Julien Grall <jgr...@amazon.com>
Signed-off-by: Henry Wang <henry.w...@arm.com>
---
This should also be backported to 4.13, 4.14, 4.15 and 4.16.
---
 xen/arch/arm/domain.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 2c84e6dbbb..e40e2bcba1 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -740,6 +740,20 @@ int arch_domain_create(struct domain *d,
         BUG();
     }
 
+    spin_lock(&d->arch.paging.lock);
+    /*
+     * Hardware using GICv2 needs to create a P2M mapping of 8KB GICv2 area
+     * when the domain is created. Considering the worst case for page
+     * tables and keep a buffer, populate 16 pages to the P2M pages pool here.
+     */
+    if ( (rc = p2m_set_allocation(d, 16, NULL)) != 0 )
+    {
+        p2m_set_allocation(d, 0, NULL);
+        spin_unlock(&d->arch.paging.lock);
+        goto fail;
+    }
+    spin_unlock(&d->arch.paging.lock);
+
     if ( (rc = domain_vgic_register(d, &count)) != 0 )
         goto fail;
 
-- 
2.17.1