[UNIKRAFT PATCH v5 3/7] plat/kvm: arm64: Enable the fp/simd at the starting point

[Jia He <justin.he@xxxxxxx>]

Write the sys reg to enable the fp/simd feature, otherwise it will
cause floating point/simd exception when touching q0-q31.

Signed-off-by: Jia He <justin.he@xxxxxxx>
Reviewed-by: Sharan Santhanam <sharan.santhanam@xxxxxxxxx>
---
 plat/kvm/arm/entry64.S | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/plat/kvm/arm/entry64.S b/plat/kvm/arm/entry64.S
index 359a310..c4de334 100644
--- a/plat/kvm/arm/entry64.S
+++ b/plat/kvm/arm/entry64.S
@@ -36,6 +36,7 @@
 #include <kvm-arm/mm.h>
 #include <arm/cpu_defs.h>
 #include <uk/plat/common/sections.h>
+#include <uk/config.h>
 
 .global page_table_size
 .data
@@ -49,6 +50,13 @@ page_table_size:
 
 .text
 ENTRY(_libkvmplat_entry)
+#ifdef CONFIG_FPSIMD
+       /* Enable fp/simd support */
+       ldr        x0, =(3 << 20)
+       msr        cpacr_el1, x0
+       isb
+#endif
+
        /* Calculate the image size */
        ldr x25, =_dtb
        ldr x26, =_end
-- 
2.17.1