[Xen-devel] [PATCH v7 for-next 01/12] x86/pio: allow internal PIO handlers to return RETRY

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

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@xxxxxxxxxx>
---
Cc: Paul Durrant <paul.durrant@xxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
Note this is not an issue currently because no internal handlers
return RETRY.
---
 xen/arch/x86/hvm/io.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/hvm/io.c b/xen/arch/x86/hvm/io.c
index e449b4196e..10e1e2db45 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;
 
-- 
2.13.5 (Apple Git-94)


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