5 files changed, 149 insertions, 6 deletions

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index bcd6e5d3c89a..aa40bef09dfc 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -19,6 +19,7 @@
 #include <linux/kvm_irqfd.h>
 #include <linux/irqbypass.h>
 #include <linux/sched/stat.h>
+#include <linux/psci.h>
 #include <trace/events/kvm.h>
 
 #define CREATE_TRACE_POINTS
@@ -65,6 +66,8 @@ static DEFINE_PER_CPU(unsigned char, kvm_arm_hardware_enabled);
 DEFINE_STATIC_KEY_FALSE(userspace_irqchip_in_use);
 
 extern u64 kvm_nvhe_sym(__cpu_logical_map)[NR_CPUS];
+extern u32 kvm_nvhe_sym(kvm_host_psci_version);
+extern struct psci_0_1_function_ids kvm_nvhe_sym(kvm_host_psci_0_1_function_ids);
 
 int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
 {
@@ -1522,6 +1525,22 @@ static void init_cpu_logical_map(void)
 		kvm_nvhe_sym(__cpu_logical_map)[cpu] = cpu_logical_map(cpu);
 }
 
+static bool init_psci_relay(void)
+{
+	/*
+	 * If PSCI has not been initialized, protected KVM cannot install
+	 * itself on newly booted CPUs.
+	 */
+	if (!psci_ops.get_version) {
+		kvm_err("Cannot initialize protected mode without PSCI\n");
+		return false;
+	}
+
+	kvm_nvhe_sym(kvm_host_psci_version) = psci_ops.get_version();
+	kvm_nvhe_sym(kvm_host_psci_0_1_function_ids) = get_psci_0_1_function_ids();
+	return true;
+}
+
 static int init_common_resources(void)
 {
 	return kvm_set_ipa_limit();
@@ -1700,9 +1719,13 @@ static int init_hyp_mode(void)
 		}
 	}
 
-	if (is_protected_kvm_enabled())
+	if (is_protected_kvm_enabled()) {
 		init_cpu_logical_map();
 
+		if (!init_psci_relay())
+			goto out_err;
+	}
+
 	return 0;
 
 out_err:
diff --git a/arch/arm64/kvm/hyp/include/nvhe/trap_handler.h b/arch/arm64/kvm/hyp/include/nvhe/trap_handler.h
new file mode 100644
index 000000000000..1e6d995968a1
--- /dev/null
+++ b/arch/arm64/kvm/hyp/include/nvhe/trap_handler.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Trap handler helpers.
+ *
+ * Copyright (C) 2020 - Google LLC
+ * Author: Marc Zyngier <maz@kernel.org>
+ */
+
+#ifndef __ARM64_KVM_NVHE_TRAP_HANDLER_H__
+#define __ARM64_KVM_NVHE_TRAP_HANDLER_H__
+
+#include <asm/kvm_host.h>
+
+#define cpu_reg(ctxt, r)	(ctxt)->regs.regs[r]
+#define DECLARE_REG(type, name, ctxt, reg)	\
+				type name = (type)cpu_reg(ctxt, (reg))
+
+#endif /* __ARM64_KVM_NVHE_TRAP_HANDLER_H__ */
diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index 2d842e009a40..bf62c8e42ab2 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -7,7 +7,7 @@ asflags-y := -D__KVM_NVHE_HYPERVISOR__
 ccflags-y := -D__KVM_NVHE_HYPERVISOR__
 
 obj-y := timer-sr.o sysreg-sr.o debug-sr.o switch.o tlb.o hyp-init.o host.o \
-	 hyp-main.o hyp-smp.o
+	 hyp-main.o hyp-smp.o psci-relay.o
 obj-y += ../vgic-v3-sr.o ../aarch32.o ../vgic-v2-cpuif-proxy.o ../entry.o \
 	 ../fpsimd.o ../hyp-entry.o
 
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index f25680ede080..bde658d51404 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -12,9 +12,7 @@
 #include <asm/kvm_hyp.h>
 #include <asm/kvm_mmu.h>
 
-#define cpu_reg(ctxt, r)	(ctxt)->regs.regs[r]
-#define DECLARE_REG(type, name, ctxt, reg)	\
-				type name = (type)cpu_reg(ctxt, (reg))
+#include <nvhe/trap_handler.h>
 
 DEFINE_PER_CPU(struct kvm_nvhe_init_params, kvm_init_params);
 
@@ -166,7 +164,11 @@ static void skip_host_instruction(void)
 
 static void handle_host_smc(struct kvm_cpu_context *host_ctxt)
 {
-	default_host_smc_handler(host_ctxt);
+	bool handled;
+
+	handled = kvm_host_psci_handler(host_ctxt);
+	if (!handled)
+		default_host_smc_handler(host_ctxt);
 
 	/*
 	 * Unlike HVC, the return address of an SMC is the instruction's PC.
diff --git a/arch/arm64/kvm/hyp/nvhe/psci-relay.c b/arch/arm64/kvm/hyp/nvhe/psci-relay.c
new file mode 100644
index 000000000000..61375d4571c2
--- /dev/null
+++ b/arch/arm64/kvm/hyp/nvhe/psci-relay.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 - Google LLC
+ * Author: David Brazdil <dbrazdil@google.com>
+ */
+
+#include <asm/kvm_asm.h>
+#include <asm/kvm_hyp.h>
+#include <asm/kvm_mmu.h>
+#include <kvm/arm_hypercalls.h>
+#include <linux/arm-smccc.h>
+#include <linux/psci.h>
+#include <kvm/arm_psci.h>
+#include <uapi/linux/psci.h>
+
+#include <nvhe/trap_handler.h>
+
+/* Config options set by the host. */
+__ro_after_init u32 kvm_host_psci_version;
+__ro_after_init struct psci_0_1_function_ids kvm_host_psci_0_1_function_ids;
+
+static u64 get_psci_func_id(struct kvm_cpu_context *host_ctxt)
+{
+	DECLARE_REG(u64, func_id, host_ctxt, 0);
+
+	return func_id;
+}
+
+static bool is_psci_0_1_call(u64 func_id)
+{
+	return (func_id == kvm_host_psci_0_1_function_ids.cpu_suspend) ||
+	       (func_id == kvm_host_psci_0_1_function_ids.cpu_on) ||
+	       (func_id == kvm_host_psci_0_1_function_ids.cpu_off) ||
+	       (func_id == kvm_host_psci_0_1_function_ids.migrate);
+}
+
+static bool is_psci_0_2_call(u64 func_id)
+{
+	/* SMCCC reserves IDs 0x00-1F with the given 32/64-bit base for PSCI. */
+	return (PSCI_0_2_FN(0) <= func_id && func_id <= PSCI_0_2_FN(31)) ||
+	       (PSCI_0_2_FN64(0) <= func_id && func_id <= PSCI_0_2_FN64(31));
+}
+
+static bool is_psci_call(u64 func_id)
+{
+	switch (kvm_host_psci_version) {
+	case PSCI_VERSION(0, 1):
+		return is_psci_0_1_call(func_id);
+	default:
+		return is_psci_0_2_call(func_id);
+	}
+}
+
+static unsigned long psci_0_1_handler(u64 func_id, struct kvm_cpu_context *host_ctxt)
+{
+	return PSCI_RET_NOT_SUPPORTED;
+}
+
+static unsigned long psci_0_2_handler(u64 func_id, struct kvm_cpu_context *host_ctxt)
+{
+	switch (func_id) {
+	default:
+		return PSCI_RET_NOT_SUPPORTED;
+	}
+}
+
+static unsigned long psci_1_0_handler(u64 func_id, struct kvm_cpu_context *host_ctxt)
+{
+	switch (func_id) {
+	default:
+		return psci_0_2_handler(func_id, host_ctxt);
+	}
+}
+
+bool kvm_host_psci_handler(struct kvm_cpu_context *host_ctxt)
+{
+	u64 func_id = get_psci_func_id(host_ctxt);
+	unsigned long ret;
+
+	if (!is_psci_call(func_id))
+		return false;
+
+	switch (kvm_host_psci_version) {
+	case PSCI_VERSION(0, 1):
+		ret = psci_0_1_handler(func_id, host_ctxt);
+		break;
+	case PSCI_VERSION(0, 2):
+		ret = psci_0_2_handler(func_id, host_ctxt);
+		break;
+	default:
+		ret = psci_1_0_handler(func_id, host_ctxt);
+		break;
+	}
+
+	cpu_reg(host_ctxt, 0) = ret;
+	cpu_reg(host_ctxt, 1) = 0;
+	cpu_reg(host_ctxt, 2) = 0;
+	cpu_reg(host_ctxt, 3) = 0;
+	return true;
+}