KVM: x86: Fix wrong masking on relative jump/call
commit 05c83ec9b73c8124555b706f6af777b10adf0862 upstream.
Relative jumps and calls do the masking according to the operand size, and not
according to the address size as the KVM emulator does today.
This patch fixes KVM behavior.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index fb3fddc..450a8cba 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -663,11 +663,6 @@
masked_increment(reg_rmw(ctxt, VCPU_REGS_RSP), stack_mask(ctxt), inc);
}
-static inline void jmp_rel(struct x86_emulate_ctxt *ctxt, int rel)
-{
- register_address_increment(ctxt, &ctxt->_eip, rel);
-}
-
static u32 desc_limit_scaled(struct desc_struct *desc)
{
u32 limit = get_desc_limit(desc);
@@ -741,6 +736,28 @@
return emulate_exception(ctxt, NM_VECTOR, 0, false);
}
+static inline void assign_eip_near(struct x86_emulate_ctxt *ctxt, ulong dst)
+{
+ switch (ctxt->op_bytes) {
+ case 2:
+ ctxt->_eip = (u16)dst;
+ break;
+ case 4:
+ ctxt->_eip = (u32)dst;
+ break;
+ case 8:
+ ctxt->_eip = dst;
+ break;
+ default:
+ WARN(1, "unsupported eip assignment size\n");
+ }
+}
+
+static inline void jmp_rel(struct x86_emulate_ctxt *ctxt, int rel)
+{
+ assign_eip_near(ctxt, ctxt->_eip + rel);
+}
+
static u16 get_segment_selector(struct x86_emulate_ctxt *ctxt, unsigned seg)
{
u16 selector;