ARM: KVM: Add TLB invalidation code

Convert the TLB invalidation code to C, hooking it into the
build system whilst we're at it.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

arch/arm/kvm/Makefile

@@ -17,6 +17,7 @@ AFLAGS_interrupts.o := -Wa,-march=armv7-a$(plus_virt)
 KVM := ../../../virt/kvm
 kvm-arm-y = $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o $(KVM)/vfio.o
 
+obj-$(CONFIG_KVM_ARM_HOST) += hyp/
 obj-y += kvm-arm.o init.o interrupts.o
 obj-y += arm.o handle_exit.o guest.o mmu.o emulate.o reset.o
 obj-y += coproc.o coproc_a15.o coproc_a7.o mmio.o psci.o perf.o

arch/arm/kvm/hyp/Makefile

@@ -0,0 +1,5 @@
+#
+# Makefile for Kernel-based Virtual Machine module, HYP part
+#
+
+obj-$(CONFIG_KVM_ARM_HOST) += tlb.o

arch/arm/kvm/hyp/hyp.h

@@ -42,4 +42,9 @@
 })
 #define read_sysreg(...)		__read_sysreg(__VA_ARGS__)
 
+#define VTTBR		__ACCESS_CP15_64(6, c2)
+#define ICIALLUIS	__ACCESS_CP15(c7, 0, c1, 0)
+#define TLBIALLIS	__ACCESS_CP15(c8, 0, c3, 0)
+#define TLBIALLNSNHIS	__ACCESS_CP15(c8, 4, c3, 4)
+
 #endif /* __ARM_KVM_HYP_H__ */

arch/arm/kvm/hyp/tlb.c

@@ -0,0 +1,70 @@
+/*
+ * Original code:
+ * Copyright (C) 2012 - Virtual Open Systems and Columbia University
+ * Author: Christoffer Dall <c.dall@virtualopensystems.com>
+ *
+ * Mostly rewritten in C by 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 "hyp.h"
+
+/**
+ * Flush per-VMID TLBs
+ *
+ * __kvm_tlb_flush_vmid(struct kvm *kvm);
+ *
+ * We rely on the hardware to broadcast the TLB invalidation to all CPUs
+ * inside the inner-shareable domain (which is the case for all v7
+ * implementations).  If we come across a non-IS SMP implementation, we'll
+ * have to use an IPI based mechanism. Until then, we stick to the simple
+ * hardware assisted version.
+ *
+ * As v7 does not support flushing per IPA, just nuke the whole TLB
+ * instead, ignoring the ipa value.
+ */
+static void __hyp_text __tlb_flush_vmid(struct kvm *kvm)
+{
+	dsb(ishst);
+
+	/* Switch to requested VMID */
+	kvm = kern_hyp_va(kvm);
+	write_sysreg(kvm->arch.vttbr, VTTBR);
+	isb();
+
+	write_sysreg(0, TLBIALLIS);
+	dsb(ish);
+	isb();
+
+	write_sysreg(0, VTTBR);
+}
+
+__alias(__tlb_flush_vmid) void __weak __kvm_tlb_flush_vmid(struct kvm *kvm);
+
+static void __hyp_text __tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)
+{
+	__tlb_flush_vmid(kvm);
+}
+
+__alias(__tlb_flush_vmid_ipa) void __weak __kvm_tlb_flush_vmid_ipa(struct kvm *kvm,
+							    phys_addr_t ipa);
+
+static void __hyp_text __tlb_flush_vm_context(void)
+{
+	write_sysreg(0, TLBIALLNSNHIS);
+	write_sysreg(0, ICIALLUIS);
+	dsb(ish);
+}
+
+__alias(__tlb_flush_vm_context) void __weak __kvm_flush_vm_context(void);