KVM: x86: introduce linear_{read,write}_system

Wrap the common invocation of ctxt->ops->read_std and ctxt->ops->write_std, so
as to have a smaller patch when the functions grow another argument.

Fixes: 129a72a0 ("KVM: x86: Introduce segmented_write_std", 2017-01-12)
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/emulate.c

@@ -812,6 +812,19 @@ static inline int jmp_rel(struct x86_emulate_ctxt *ctxt, int rel)
 	return assign_eip_near(ctxt, ctxt->_eip + rel);
 }
 
+static int linear_read_system(struct x86_emulate_ctxt *ctxt, ulong linear,
+			      void *data, unsigned size)
+{
+	return ctxt->ops->read_std(ctxt, linear, data, size, &ctxt->exception);
+}
+
+static int linear_write_system(struct x86_emulate_ctxt *ctxt,
+			       ulong linear, void *data,
+			       unsigned int size)
+{
+	return ctxt->ops->write_std(ctxt, linear, data, size, &ctxt->exception);
+}
+
 static int segmented_read_std(struct x86_emulate_ctxt *ctxt,
 			      struct segmented_address addr,
 			      void *data,
@@ -1496,8 +1509,7 @@ static int read_interrupt_descriptor(struct x86_emulate_ctxt *ctxt,
 		return emulate_gp(ctxt, index << 3 | 0x2);
 
 	addr = dt.address + index * 8;
-	return ctxt->ops->read_std(ctxt, addr, desc, sizeof *desc,
-				   &ctxt->exception);
+	return linear_read_system(ctxt, addr, desc, sizeof *desc);
 }
 
 static void get_descriptor_table_ptr(struct x86_emulate_ctxt *ctxt,
@@ -1560,8 +1572,7 @@ static int read_segment_descriptor(struct x86_emulate_ctxt *ctxt,
 	if (rc != X86EMUL_CONTINUE)
 		return rc;
 
-	return ctxt->ops->read_std(ctxt, *desc_addr_p, desc, sizeof(*desc),
-				   &ctxt->exception);
+	return linear_read_system(ctxt, *desc_addr_p, desc, sizeof(*desc));
 }
 
 /* allowed just for 8 bytes segments */
@@ -1575,8 +1586,7 @@ static int write_segment_descriptor(struct x86_emulate_ctxt *ctxt,
 	if (rc != X86EMUL_CONTINUE)
 		return rc;
 
-	return ctxt->ops->write_std(ctxt, addr, desc, sizeof *desc,
-				    &ctxt->exception);
+	return linear_write_system(ctxt, addr, desc, sizeof *desc);
 }
 
 static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
@@ -1737,8 +1747,7 @@ static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
 				return ret;
 		}
 	} else if (ctxt->mode == X86EMUL_MODE_PROT64) {
-		ret = ctxt->ops->read_std(ctxt, desc_addr+8, &base3,
-				sizeof(base3), &ctxt->exception);
+		ret = linear_read_system(ctxt, desc_addr+8, &base3, sizeof(base3));
 		if (ret != X86EMUL_CONTINUE)
 			return ret;
 		if (emul_is_noncanonical_address(get_desc_base(&seg_desc) |
@@ -2051,11 +2060,11 @@ static int __emulate_int_real(struct x86_emulate_ctxt *ctxt, int irq)
 	eip_addr = dt.address + (irq << 2);
 	cs_addr = dt.address + (irq << 2) + 2;
 
-	rc = ops->read_std(ctxt, cs_addr, &cs, 2, &ctxt->exception);
+	rc = linear_read_system(ctxt, cs_addr, &cs, 2);
 	if (rc != X86EMUL_CONTINUE)
 		return rc;
 
-	rc = ops->read_std(ctxt, eip_addr, &eip, 2, &ctxt->exception);
+	rc = linear_read_system(ctxt, eip_addr, &eip, 2);
 	if (rc != X86EMUL_CONTINUE)
 		return rc;
 
@@ -3053,35 +3062,30 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
 			  u16 tss_selector, u16 old_tss_sel,
 			  ulong old_tss_base, struct desc_struct *new_desc)
 {
-	const struct x86_emulate_ops *ops = ctxt->ops;
 	struct tss_segment_16 tss_seg;
 	int ret;
 	u32 new_tss_base = get_desc_base(new_desc);
 
-	ret = ops->read_std(ctxt, old_tss_base, &tss_seg, sizeof tss_seg,
-			    &ctxt->exception);
+	ret = linear_read_system(ctxt, old_tss_base, &tss_seg, sizeof tss_seg);
 	if (ret != X86EMUL_CONTINUE)
 		return ret;
 
 	save_state_to_tss16(ctxt, &tss_seg);
 
-	ret = ops->write_std(ctxt, old_tss_base, &tss_seg, sizeof tss_seg,
-			     &ctxt->exception);
+	ret = linear_write_system(ctxt, old_tss_base, &tss_seg, sizeof tss_seg);
 	if (ret != X86EMUL_CONTINUE)
 		return ret;
 
-	ret = ops->read_std(ctxt, new_tss_base, &tss_seg, sizeof tss_seg,
-			    &ctxt->exception);
+	ret = linear_read_system(ctxt, new_tss_base, &tss_seg, sizeof tss_seg);
 	if (ret != X86EMUL_CONTINUE)
 		return ret;
 
 	if (old_tss_sel != 0xffff) {
 		tss_seg.prev_task_link = old_tss_sel;
 
-		ret = ops->write_std(ctxt, new_tss_base,
-				     &tss_seg.prev_task_link,
-				     sizeof tss_seg.prev_task_link,
-				     &ctxt->exception);
+		ret = linear_write_system(ctxt, new_tss_base,
+					  &tss_seg.prev_task_link,
+					  sizeof tss_seg.prev_task_link);
 		if (ret != X86EMUL_CONTINUE)
 			return ret;
 	}
@@ -3197,38 +3201,34 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
 			  u16 tss_selector, u16 old_tss_sel,
 			  ulong old_tss_base, struct desc_struct *new_desc)
 {
-	const struct x86_emulate_ops *ops = ctxt->ops;
 	struct tss_segment_32 tss_seg;
 	int ret;
 	u32 new_tss_base = get_desc_base(new_desc);
 	u32 eip_offset = offsetof(struct tss_segment_32, eip);
 	u32 ldt_sel_offset = offsetof(struct tss_segment_32, ldt_selector);
 
-	ret = ops->read_std(ctxt, old_tss_base, &tss_seg, sizeof tss_seg,
-			    &ctxt->exception);
+	ret = linear_read_system(ctxt, old_tss_base, &tss_seg, sizeof tss_seg);
 	if (ret != X86EMUL_CONTINUE)
 		return ret;
 
 	save_state_to_tss32(ctxt, &tss_seg);
 
 	/* Only GP registers and segment selectors are saved */
-	ret = ops->write_std(ctxt, old_tss_base + eip_offset, &tss_seg.eip,
-			     ldt_sel_offset - eip_offset, &ctxt->exception);
+	ret = linear_write_system(ctxt, old_tss_base + eip_offset, &tss_seg.eip,
+				  ldt_sel_offset - eip_offset);
 	if (ret != X86EMUL_CONTINUE)
 		return ret;
 
-	ret = ops->read_std(ctxt, new_tss_base, &tss_seg, sizeof tss_seg,
-			    &ctxt->exception);
+	ret = linear_read_system(ctxt, new_tss_base, &tss_seg, sizeof tss_seg);
 	if (ret != X86EMUL_CONTINUE)
 		return ret;
 
 	if (old_tss_sel != 0xffff) {
 		tss_seg.prev_task_link = old_tss_sel;
 
-		ret = ops->write_std(ctxt, new_tss_base,
-				     &tss_seg.prev_task_link,
-				     sizeof tss_seg.prev_task_link,
-				     &ctxt->exception);
+		ret = linear_write_system(ctxt, new_tss_base,
+					  &tss_seg.prev_task_link,
+					  sizeof tss_seg.prev_task_link);
 		if (ret != X86EMUL_CONTINUE)
 			return ret;
 	}