arm64: KVM: CPU specific system registers handling

Add the support code for CPU specific system registers. Not much
here yet.
Reviewed-by: Christopher Covington <cov@codeaurora.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

arch/arm64/kvm/sys_regs_generic_v8.c

+/*
+ * Copyright (C) 2012,2013 - ARM Ltd
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ *
+ * Based on arch/arm/kvm/coproc_a15.c:
+ * Copyright (C) 2012 - Virtual Open Systems and Columbia University
+ * Authors: Rusty Russell <rusty@rustcorp.au>
+ *          Christoffer Dall <c.dall@virtualopensystems.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <linux/kvm_host.h>
+#include <asm/cputype.h>
+#include <asm/kvm_arm.h>
+#include <asm/kvm_asm.h>
+#include <asm/kvm_host.h>
+#include <asm/kvm_emulate.h>
+#include <asm/kvm_coproc.h>
+#include <linux/init.h>
+
+#include "sys_regs.h"
+
+static bool access_actlr(struct kvm_vcpu *vcpu,
+			 const struct sys_reg_params *p,
+			 const struct sys_reg_desc *r)
+{
+	if (p->is_write)
+		return ignore_write(vcpu, p);
+
+	*vcpu_reg(vcpu, p->Rt) = vcpu_sys_reg(vcpu, ACTLR_EL1);
+	return true;
+}
+
+static void reset_actlr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+{
+	u64 actlr;
+
+	asm volatile("mrs %0, actlr_el1\n" : "=r" (actlr));
+	vcpu_sys_reg(vcpu, ACTLR_EL1) = actlr;
+}
+
+/*
+ * Implementation specific sys-reg registers.
+ * Important: Must be sorted ascending by Op0, Op1, CRn, CRm, Op2
+ */
+static const struct sys_reg_desc genericv8_sys_regs[] = {
+	/* ACTLR_EL1 */
+	{ Op0(0b11), Op1(0b000), CRn(0b0001), CRm(0b0000), Op2(0b001),
+	  access_actlr, reset_actlr, ACTLR_EL1 },
+};
+
+static struct kvm_sys_reg_target_table genericv8_target_table = {
+	.table64 = {
+		.table = genericv8_sys_regs,
+		.num = ARRAY_SIZE(genericv8_sys_regs),
+	},
+};
+
+static int __init sys_reg_genericv8_init(void)
+{
+	unsigned int i;
+
+	for (i = 1; i < ARRAY_SIZE(genericv8_sys_regs); i++)
+		BUG_ON(cmp_sys_reg(&genericv8_sys_regs[i-1],
+			       &genericv8_sys_regs[i]) >= 0);
+
+	kvm_register_target_sys_reg_table(KVM_ARM_TARGET_AEM_V8,
+					  &genericv8_target_table);
+	kvm_register_target_sys_reg_table(KVM_ARM_TARGET_FOUNDATION_V8,
+					  &genericv8_target_table);
+	kvm_register_target_sys_reg_table(KVM_ARM_TARGET_CORTEX_A57,
+					  &genericv8_target_table);
+	return 0;
+}
+late_initcall(sys_reg_genericv8_init);