[PATCH v8 18/26] emul/ns16x50: resolve physical I/O port sharing

[dmukhin@xxxxxxxx]

From: Denis Mukhin <dmukhin@xxxxxxxx>

Ensure NS16550 emulator does not share I/O ports with the physical I/O
ports, which is essential for emulation in PVH hwdom case (dom0).

Signed-off-by: Denis Mukhin <dmukhin@xxxxxxxx>
---
 xen/common/emul/vuart/ns16x50.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/xen/common/emul/vuart/ns16x50.c b/xen/common/emul/vuart/ns16x50.c
index cda21c15cf78..97e12a99368a 100644
--- a/xen/common/emul/vuart/ns16x50.c
+++ b/xen/common/emul/vuart/ns16x50.c
@@ -901,14 +901,27 @@ static int ns16x50_init(void *arg)
     struct vuart_ns16x50 *vdev = arg;
     const struct vuart_info *info;
     struct domain *d;
+    const char *as;
+    int rc;
 
     ASSERT(vdev);
 
     d = vdev->owner;
     info = vdev->info;
+    as = (info->base_type & IORESOURCE_IO) ? "ioport": "iomem";
 
     if ( info->base_type & IORESOURCE_IO )
     {
+        /* Disallow sharing physical I/O port */
+        rc = ioports_deny_access(d, info->base_addr,
+                                 info->base_addr + info->size - 1);
+        if ( rc )
+        {
+            ns16x50_err(info, "virtual %s range [%#"PRIx64"..%#"PRIx64"]: 
conflict w/ physical range\n",
+                        as, info->base_addr, info->base_addr + info->size - 1);
+            return rc;
+        }
+
         register_portio_handler(d, info->base_addr, info->size, 
ns16x50_io_handle);
     }
     else if ( info->base_type & IORESOURCE_MEM )
@@ -928,13 +941,20 @@ static int ns16x50_init(void *arg)
 static void cf_check ns16x50_deinit(void *arg)
 {
     struct vuart_ns16x50 *vdev = arg;
+    const struct vuart_info *info;
     unsigned long flags;
 
     ASSERT(vdev);
 
+    info = vdev->info;
+
     ns16x50_lock(vdev, &flags);
     ns16x50_fifo_tx_flush(vdev);
     ns16x50_unlock(vdev, &flags);
+
+    if ( info->base_type & IORESOURCE_IO )
+        ioports_permit_access(d, info->base_addr,
+                              info->base_addr + info->size - 1);
 }
 
 static void * cf_check ns16x50_alloc(struct domain *d, const struct vuart_info 
*info)
-- 
2.56.0