The table of offsets to real-mode hcall handlers in book3s_hv_rmhandlers.S
can contain negative values, if some of the handlers end up before the
table in the vmlinux binary. Thus we need to use a sign-extending load
to read the values in the table rather than a zero-extending load.
Without this, the host crashes when the guest does one of the hcalls
with negative offsets, due to jumping to a bogus address.
Signed-off-by: Paul Mackerras <pau...@samba.org>
Cc: sta...@vger.kernel.org
---
arch/powerpc/kvm/book3s_hv_rmhandlers.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index b02f91e..60dce5b 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -1381,7 +1381,7 @@ hcall_try_real_mode:
cmpldi r3,hcall_real_table_end - hcall_real_table
bge guest_exit_cont
LOAD_REG_ADDR(r4, hcall_real_table)
- lwzx r3,r3,r4
+ lwax r3,r3,r4
cmpwi r3,0
beq guest_exit_cont
add r3,r3,r4
--
1.8.3.1
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