From: Roger Pau Monné <roger.pau@citrix.com>
Date: Mon, 4 Dec 2017 10:02:16 +0000 (+0100)
Subject: x86/pio: allow internal PIO handlers to return RETRY
X-Git-Tag: archive/raspbian/4.11.1-1+rpi1~1^2~66^2~969
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=8202ebb1124d90f26f47cee78c813d00c935e77b;p=xen.git

x86/pio: allow internal PIO handlers to return RETRY

Fix handle_pio so internal PIO handlers can return X86EMUL_RETRY and
it is properly handled by not advancing the IP.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Paul Durrant <paul.durrant@citrix.com>
---

diff --git a/xen/arch/x86/hvm/io.c b/xen/arch/x86/hvm/io.c
index 9d9e1b0e40..7e8b8ac61c 100644
--- a/xen/arch/x86/hvm/io.c
+++ b/xen/arch/x86/hvm/io.c
@@ -157,8 +157,11 @@ bool handle_pio(uint16_t port, unsigned int size, int dir)
         break;
 
     case X86EMUL_RETRY:
-        /* We should not advance RIP/EIP if the domain is shutting down */
-        if ( curr->domain->is_shutting_down )
+        /*
+         * We should not advance RIP/EIP if the domain is shutting down or
+         * if X86EMUL_RETRY has been returned by an internal handler.
+         */
+        if ( curr->domain->is_shutting_down || !hvm_io_pending(curr) )
             return false;
         break;