Disable SMAP in the shim before bouncing the hypercall, or else L0
will fail to get the hypercall buffer.
Signed-off-by: Roger Pau Monné <roger....@citrix.com>
Reported-by: Fatih Acar <fatih.a...@gandi.net>
---
Cc: Jan Beulich <jbeul...@suse.com>
Cc: Andrew Cooper <andrew.coop...@citrix.com>
Cc: Ian Jackson <ian.jack...@eu.citrix.com>
Cc: Wei Liu <wei.l...@citrix.com>
---
Needs to be backported to the 4.10.0-shim-comet branch.
---
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 d5383dcfc7..eb1ee7d3c4 100644
--- a/xen/arch/x86/pv/shim.c
+++ b/xen/arch/x86/pv/shim.c
@@ -748,7 +748,10 @@ 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:
--
2.15.1
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