[PATCH v7 4/7] xen/arm: account IO handler for emulated PCI host bridge

[Oleksandr Andrushchenko <andr2000@gmail.com>]

From: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>

At the moment, we always allocate an extra 16 slots for IO handlers
(see MAX_IO_HANDLER). So while adding an IO trap handler for the emulated
PCI host bridge we are not breaking anything, but we have a latent bug
as the maximum number of IOs may be exceeded.
Fix this by explicitly telling that we have an additional IO handler, so it is
accounted.

Fixes: d59168dc05a5 ("xen/arm: Enable the existing x86 virtual PCI support for ARM")

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>

---
New in v7
---
 xen/arch/arm/vpci.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/xen/arch/arm/vpci.c b/xen/arch/arm/vpci.c
index ccd998d8dba2..8e801f275879 100644
--- a/xen/arch/arm/vpci.c
+++ b/xen/arch/arm/vpci.c
@@ -126,7 +126,8 @@ unsigned int domain_vpci_get_num_mmio_handlers(struct domain *d)
         return ret < 0 ? 0 : ret;
     }
 
-    return 0;
+    /* For a single emulated host bridge's configuration space. */
+    return 1;
 }
 
 /*
-- 
2.25.1