Implement the PSCI specification (ARM DEN 0022A) to control
virtual CPUs being "powered" on or off.
The 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.
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
arch/arm/include/asm/kvm_emulate.h | 5 ++
arch/arm/include/asm/kvm_host.h | 2 +-
arch/arm/include/asm/kvm_psci.h | 23 +++++++++
arch/arm/include/uapi/asm/kvm.h | 16 ++++++
arch/arm/kvm/Makefile | 2 +-
arch/arm/kvm/arm.c | 13 +++++
arch/arm/kvm/handle_exit.c | 16 +++---
arch/arm/kvm/psci.c | 103 +++++++++++++++++++++++++++++++++++++
include/uapi/linux/kvm.h | 1 +
9 files changed, 170 insertions(+), 11 deletions(-)
create mode 100644 arch/arm/include/asm/kvm_psci.h
create mode 100644 arch/arm/kvm/psci.c
diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h
index d52cb81..b6ed67b 100644
--- a/arch/arm/include/asm/kvm_emulate.h
+++ b/arch/arm/include/asm/kvm_emulate.h
@@ -35,6 +35,11 @@ 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 unsigned long *vcpu_pc(struct kvm_vcpu *vcpu)
{
return &vcpu->arch.regs.usr_regs.ARM_pc;
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index fe8153a..39fc844 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -31,7 +31,7 @@
#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
diff --git a/arch/arm/include/asm/kvm_psci.h b/arch/arm/include/asm/kvm_psci.h
new file mode 100644
index 0000000..992d7f1
--- /dev/null
+++ b/arch/arm/include/asm/kvm_psci.h
@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2012 - ARM Ltd
+ * Author: Marc Zyngier <marc.zyngier@xxxxxxx>
+ *
+ * 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__
+
+int 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 974f8b0..3c9663c 100644
--- a/arch/arm/include/uapi/asm/kvm.h
+++ b/arch/arm/include/uapi/asm/kvm.h
@@ -81,6 +81,8 @@ struct kvm_regs {
#define KVM_VGIC_V2_DIST_SIZE 0x1000
#define KVM_VGIC_V2_CPU_SIZE 0x2000
+#define KVM_ARM_VCPU_POWER_OFF 0 /* CPU is started in OFF state */
+
struct kvm_vcpu_init {
__u32 target;
__u32 features[7];
@@ -161,4 +163,18 @@ 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__ */
diff --git a/arch/arm/kvm/Makefile b/arch/arm/kvm/Makefile
index 81823c1..1974ba0 100644
--- a/arch/arm/kvm/Makefile
+++ b/arch/arm/kvm/Makefile
@@ -18,6 +18,6 @@ kvm-arm-y = $(addprefix ../../../virt/kvm/, kvm_main.o coalesced_mmio.o)
obj-y += kvm-arm.o init.o interrupts.o
obj-y += arm.o handle_exit.o guest.o mmu.o emulate.o reset.o
-obj-y += coproc.o coproc_a15.o mmio.o decode.o
+obj-y += coproc.o coproc_a15.o mmio.o decode.o psci.o
obj-$(CONFIG_KVM_ARM_VGIC) += vgic.o
obj-$(CONFIG_KVM_ARM_TIMER) += arch_timer.o
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index d16712d..15e1700 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -41,6 +41,7 @@
#include <asm/kvm_mmu.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_coproc.h>
+#include <asm/kvm_psci.h>
#ifdef REQUIRES_VIRT
__asm__(".arch_extension virt");
@@ -189,6 +190,7 @@ int kvm_dev_ioctl_check_extension(long ext)
case KVM_CAP_SYNC_MMU:
case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
case KVM_CAP_ONE_REG:
+ case KVM_CAP_ARM_PSCI:
r = 1;
break;
case KVM_CAP_COALESCED_MMIO:
@@ -504,6 +506,17 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
return ret;
}
+ /*
+ * Handle the "start in power-off" case by calling into the
+ * PSCI code. This only happens once in the lifetime of a
+ * vcpu.
+ */
+ if (unlikely(test_and_clear_bit(KVM_ARM_VCPU_POWER_OFF,
+ vcpu->arch.features))) {
+ *vcpu_reg(vcpu, 0) = KVM_PSCI_FN_CPU_OFF;
+ kvm_psci_call(vcpu);
+ }
+
if (vcpu->sigset_active)
sigprocmask(SIG_SETMASK, &vcpu->sigset, &sigsaved);
diff --git a/arch/arm/kvm/handle_exit.c b/arch/arm/kvm/handle_exit.c
index f2fc5fa..de86710 100644
--- a/arch/arm/kvm/handle_exit.c
+++ b/arch/arm/kvm/handle_exit.c
@@ -21,6 +21,7 @@
#include <asm/kvm_emulate.h>
#include <asm/kvm_coproc.h>
#include <asm/kvm_mmu.h>
+#include <asm/kvm_psci.h>
#include <trace/events/kvm.h>
#include "trace.h"
@@ -37,21 +38,18 @@ static int handle_svc_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
- /*
- * Guest called HVC instruction:
- * Let it know we don't want that by injecting an undefined exception.
- */
- kvm_debug("hvc: %x (at %08lx)", kvm_vcpu_get_hsr(vcpu) & ((1 << 16) - 1),
- *vcpu_pc(vcpu));
- kvm_debug(" HSR: %8x", kvm_vcpu_get_hsr(vcpu));
+ if (!kvm_psci_call(vcpu))
+ return 1;
+
kvm_inject_undefined(vcpu);
return 1;
}
static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
- /* We don't support SMC; don't do that. */
- kvm_debug("smc: at %08lx", *vcpu_pc(vcpu));
+ if (!kvm_psci_call(vcpu))
+ return 1;
+
kvm_inject_undefined(vcpu);
return 1;
}
diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c
new file mode 100644
index 0000000..d59f763
--- /dev/null
+++ b/arch/arm/kvm/psci.c
@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2012 - ARM Ltd
+ * Author: Marc Zyngier <marc.zyngier@xxxxxxx>
+ *
+ * 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 <linux/sched.h>
+
+#include <asm/kvm_emulate.h>
+#include <asm/kvm_psci.h>
+
+static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu)
+{
+ DEFINE_WAIT(wait);
+ wait_queue_head_t *wq = kvm_arch_vcpu_wq(vcpu);
+
+ vcpu->arch.pause = true;
+
+ while (1) {
+ prepare_to_wait(wq, &wait, TASK_INTERRUPTIBLE);
+
+ if (!vcpu->arch.pause)
+ break;
+
+ if (signal_pending(current))
+ break;
+
+ schedule();
+ };
+
+ finish_wait(wq, &wait);
+}
+
+static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
+{
+ struct kvm *kvm = source_vcpu->kvm;
+ struct kvm_vcpu *vcpu;
+ wait_queue_head_t *wq;
+ unsigned long cpu_id;
+ phys_addr_t target_pc;
+
+ cpu_id = *vcpu_reg(source_vcpu, 1);
+ if (vcpu_mode_is_32bit(source_vcpu))
+ cpu_id &= ~((u32) 0);
+
+ if (cpu_id >= atomic_read(&kvm->online_vcpus))
+ return KVM_PSCI_RET_INVAL;
+
+ target_pc = *vcpu_reg(source_vcpu, 2);
+
+ vcpu = kvm_get_vcpu(kvm, cpu_id);
+
+ wq = kvm_arch_vcpu_wq(vcpu);
+ if (!waitqueue_active(wq))
+ return KVM_PSCI_RET_INVAL;
+
+ kvm_reset_vcpu(vcpu);
+ *vcpu_pc(vcpu) = target_pc;
+ vcpu->arch.pause = false;
+ smp_mb(); /* Make sure the above is visible */
+
+ wake_up_interruptible(wq);
+
+ return KVM_PSCI_RET_SUCCESS;
+}
+
+int kvm_psci_call(struct kvm_vcpu *vcpu)
+{
+ unsigned long psci_fn = *vcpu_reg(vcpu, 0) & 0xffffffff;
+ unsigned long val;
+
+ switch (psci_fn) {
+ case KVM_PSCI_FN_CPU_OFF:
+ kvm_psci_vcpu_off(vcpu);
+ val = KVM_PSCI_RET_SUCCESS;
+ break;
+ case KVM_PSCI_FN_CPU_ON:
+ val = kvm_psci_vcpu_on(vcpu);
+ break;
+ case KVM_PSCI_FN_CPU_SUSPEND:
+ case KVM_PSCI_FN_MIGRATE:
+ val = KVM_PSCI_RET_NI;
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
+ *vcpu_reg(vcpu, 0) = val;
+ return 0;
+}
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 03248d1..8233566 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -637,6 +637,7 @@ struct kvm_ppc_smmu_info {
#define KVM_CAP_PPC_BOOKE_WATCHDOG 83
#define KVM_CAP_PPC_HTAB_FD 84
#define KVM_CAP_SET_DEVICE_ADDR 85
+#define KVM_CAP_ARM_PSCI 86
#ifdef KVM_CAP_IRQ_ROUTING
--
1.8.1
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