[PATCH 3.19.y-ckt 056/128] MIPS: KVM: Fix CACHE immediate offset sign extension
Kamal Mostafa
kamal at canonical.com
Wed Dec 16 17:38:16 UTC 2015
3.19.8-ckt12 -stable review patch. If anyone has any objections, please let me know.
------------------
From: James Hogan <james.hogan at imgtec.com>
commit c5c2a3b998f1ff5a586f9d37e154070b8d550d17 upstream.
The immediate field of the CACHE instruction is signed, so ensure that
it gets sign extended by casting it to an int16_t rather than just
masking the low 16 bits.
Fixes: e685c689f3a8 ("KVM/MIPS32: Privileged instruction/target branch emulation.")
Signed-off-by: James Hogan <james.hogan at imgtec.com>
Cc: Ralf Baechle <ralf at linux-mips.org>
Cc: Paolo Bonzini <pbonzini at redhat.com>
Cc: Gleb Natapov <gleb at kernel.org>
Cc: linux-mips at linux-mips.org
Cc: kvm at vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini at redhat.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
arch/mips/kvm/emulate.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c
index 838d3a6..3d44b2d 100644
--- a/arch/mips/kvm/emulate.c
+++ b/arch/mips/kvm/emulate.c
@@ -1407,7 +1407,7 @@ enum emulation_result kvm_mips_emulate_cache(uint32_t inst, uint32_t *opc,
base = (inst >> 21) & 0x1f;
op_inst = (inst >> 16) & 0x1f;
- offset = inst & 0xffff;
+ offset = (int16_t)inst;
cache = (inst >> 16) & 0x3;
op = (inst >> 18) & 0x7;
--
1.9.1
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