KVM: ARM: Power State Coordination Interface implementation

Implement the PSCI specification (ARM DEN 0022A) to control
virtual CPUs being "powered" on or off.

PSCI/KVM is detected using the KVM_CAP_ARM_PSCI capability.

A virtual CPU can now be initialized in a "powered off" state,
using the KVM_ARM_VCPU_POWER_OFF feature flag.

The guest can use either SMC or HVC to execute a PSCI function.

Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>

4 files changed, 53 insertions, 1 deletions

diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h
index 4c1a073280be..fd611996bfb5 100644
--- a/arch/arm/include/asm/kvm_emulate.h
+++ b/arch/arm/include/asm/kvm_emulate.h
@@ -32,6 +32,11 @@ void kvm_inject_undefined(struct kvm_vcpu *vcpu);
 void kvm_inject_dabt(struct kvm_vcpu *vcpu, unsigned long addr);
 void kvm_inject_pabt(struct kvm_vcpu *vcpu, unsigned long addr);
 
+static inline bool vcpu_mode_is_32bit(struct kvm_vcpu *vcpu)
+{
+	return 1;
+}
+
 static inline u32 *vcpu_pc(struct kvm_vcpu *vcpu)
 {
 	return (u32 *)&vcpu->arch.regs.usr_regs.ARM_pc;
@@ -42,6 +47,11 @@ static inline u32 *vcpu_cpsr(struct kvm_vcpu *vcpu)
 	return (u32 *)&vcpu->arch.regs.usr_regs.ARM_cpsr;
 }
 
+static inline void vcpu_set_thumb(struct kvm_vcpu *vcpu)
+{
+	*vcpu_cpsr(vcpu) |= PSR_T_BIT;
+}
+
 static inline bool mode_has_spsr(struct kvm_vcpu *vcpu)
 {
 	unsigned long cpsr_mode = vcpu->arch.regs.usr_regs.ARM_cpsr & MODE_MASK;
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index e65fc967a71d..98b4d1a72923 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -30,7 +30,7 @@
 #define KVM_COALESCED_MMIO_PAGE_OFFSET 1
 #define KVM_HAVE_ONE_REG
 
-#define KVM_VCPU_MAX_FEATURES 0
+#define KVM_VCPU_MAX_FEATURES 1
 
 /* We don't currently support large pages. */
 #define KVM_HPAGE_GFN_SHIFT(x)	0
@@ -100,6 +100,9 @@ struct kvm_vcpu_arch {
 	int last_pcpu;
 	cpumask_t require_dcache_flush;
 
+	/* Don't run the guest on this vcpu */
+	bool pause;
+
 	/* IO related fields */
 	struct kvm_decode mmio_decode;
 
diff --git a/arch/arm/include/asm/kvm_psci.h b/arch/arm/include/asm/kvm_psci.h
new file mode 100644
index 000000000000..9a83d98bf170
--- /dev/null
+++ b/arch/arm/include/asm/kvm_psci.h
@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2012 - 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/>.
+ */
+
+#ifndef __ARM_KVM_PSCI_H__
+#define __ARM_KVM_PSCI_H__
+
+bool kvm_psci_call(struct kvm_vcpu *vcpu);
+
+#endif /* __ARM_KVM_PSCI_H__ */
diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
index bbb6b2328004..3303ff5adbf3 100644
--- a/arch/arm/include/uapi/asm/kvm.h
+++ b/arch/arm/include/uapi/asm/kvm.h
@@ -65,6 +65,8 @@ struct kvm_regs {
 #define KVM_ARM_TARGET_CORTEX_A15	0
 #define KVM_ARM_NUM_TARGETS		1
 
+#define KVM_ARM_VCPU_POWER_OFF		0 /* CPU is started in OFF state */
+
 struct kvm_vcpu_init {
 	__u32 target;
 	__u32 features[7];
@@ -145,4 +147,18 @@ struct kvm_arch_memory_slot {
 /* Highest supported SPI, from VGIC_NR_IRQS */
 #define KVM_ARM_IRQ_GIC_MAX		127
 
+/* PSCI interface */
+#define KVM_PSCI_FN_BASE		0x95c1ba5e
+#define KVM_PSCI_FN(n)			(KVM_PSCI_FN_BASE + (n))
+
+#define KVM_PSCI_FN_CPU_SUSPEND		KVM_PSCI_FN(0)
+#define KVM_PSCI_FN_CPU_OFF		KVM_PSCI_FN(1)
+#define KVM_PSCI_FN_CPU_ON		KVM_PSCI_FN(2)
+#define KVM_PSCI_FN_MIGRATE		KVM_PSCI_FN(3)
+
+#define KVM_PSCI_RET_SUCCESS		0
+#define KVM_PSCI_RET_NI			((unsigned long)-1)
+#define KVM_PSCI_RET_INVAL		((unsigned long)-2)
+#define KVM_PSCI_RET_DENIED		((unsigned long)-3)
+
 #endif /* __ARM_KVM_H__ */