ARM: KVM: Switch to C-based stage2 init

As we now have hooks to setup VTCR from C code, let's drop the
original VTCR setup and reimplement it as part of the HYP code.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

arch/arm/include/asm/kvm_asm.h

@@ -98,6 +98,8 @@ extern void __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa);
 extern void __kvm_tlb_flush_vmid(struct kvm *kvm);
 
 extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
+
+extern void __init_stage2_translation(void);
 #endif
 
 #endif /* __ARM_KVM_ASM_H__ */

arch/arm/include/asm/kvm_host.h

@@ -224,6 +224,7 @@ static inline void __cpu_init_hyp_mode(phys_addr_t boot_pgd_ptr,
 
 static inline void __cpu_init_stage2(void)
 {
+	kvm_call_hyp(__init_stage2_translation);
 }
 
 static inline int kvm_arch_dev_ioctl_check_extension(long ext)

arch/arm/kvm/hyp/Makefile

@@ -11,3 +11,4 @@ obj-$(CONFIG_KVM_ARM_HOST) += banked-sr.o
 obj-$(CONFIG_KVM_ARM_HOST) += entry.o
 obj-$(CONFIG_KVM_ARM_HOST) += hyp-entry.o
 obj-$(CONFIG_KVM_ARM_HOST) += switch.o
+obj-$(CONFIG_KVM_ARM_HOST) += s2-setup.o

arch/arm/kvm/hyp/hyp.h

@@ -71,6 +71,8 @@
 #define HCPTR		__ACCESS_CP15(c1, 4, c1, 2)
 #define HSTR		__ACCESS_CP15(c1, 4, c1, 3)
 #define TTBCR		__ACCESS_CP15(c2, 0, c0, 2)
+#define HTCR		__ACCESS_CP15(c2, 4, c0, 2)
+#define VTCR		__ACCESS_CP15(c2, 4, c1, 2)
 #define DACR		__ACCESS_CP15(c3, 0, c0, 0)
 #define DFSR		__ACCESS_CP15(c5, 0, c0, 0)
 #define IFSR		__ACCESS_CP15(c5, 0, c0, 1)

arch/arm/kvm/hyp/s2-setup.c

@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2016 - ARM Ltd
+ * Author: Marc Zyngier <marc.zyngier@arm.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/types.h>
+#include <asm/kvm_arm.h>
+#include <asm/kvm_asm.h>
+
+#include "hyp.h"
+
+void __hyp_text __init_stage2_translation(void)
+{
+	u64 val;
+
+	val = read_sysreg(VTCR) & ~VTCR_MASK;
+
+	val |= read_sysreg(HTCR) & VTCR_HTCR_SH;
+	val |= KVM_VTCR_SL0 | KVM_VTCR_T0SZ | KVM_VTCR_S;
+
+	write_sysreg(val, VTCR);
+}

arch/arm/kvm/init.S

@@ -84,14 +84,6 @@ __do_hyp_init:
 	orr	r0, r0, r1
 	mcr	p15, 4, r0, c2, c0, 2	@ HTCR
 
-	mrc	p15, 4, r1, c2, c1, 2	@ VTCR
-	ldr	r2, =VTCR_MASK
-	bic	r1, r1, r2
-	bic	r0, r0, #(~VTCR_HTCR_SH)	@ clear non-reusable HTCR bits
-	orr	r1, r0, r1
-	orr	r1, r1, #(KVM_VTCR_SL0 | KVM_VTCR_T0SZ | KVM_VTCR_S)
-	mcr	p15, 4, r1, c2, c1, 2	@ VTCR
-
 	@ Use the same memory attributes for hyp. accesses as the kernel
 	@ (copy MAIRx ro HMAIRx).
 	mrc	p15, 0, r0, c10, c2, 0