From 1124a9a26f05439a3aa31eaea227285e50dc94c0 Mon Sep 17 00:00:00 2001
From: Roger Pau Monne <roger.pau@citrix.com>
Date: Fri, 26 Jan 2018 15:29:10 +0000
Subject: [PATCH] xen/pvshim: fix GNTTABOP_query_size hypercall forwarding with
 SMAP
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Disable SMAP in the shim before bouncing the hypercall, or else L0
will fail to get the hypercall buffer.

Reported-by: Fatih Acar <fatih.acar@gandi.net>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
---
 xen/arch/x86/pv/shim.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/xen/arch/x86/pv/shim.c b/xen/arch/x86/pv/shim.c
index 6e4220886d..534965c92a 100644
--- a/xen/arch/x86/pv/shim.c
+++ b/xen/arch/x86/pv/shim.c
@@ -757,7 +757,10 @@ static long pv_shim_grant_table_op(unsigned int cmd,
     }
 
     case GNTTABOP_query_size:
+        /* Disable SMAP so L0 can access the buffer. */
+        stac();
         rc = xen_hypercall_grant_table_op(GNTTABOP_query_size, uop.p, count);
+        clac();
         break;
 
     default:
-- 
2.30.2