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.

Marc Zyngier committed 13 years ago

Commit aa024c21 parent 45e96ea9 files · +195 −4Browse files

Unified · Split

9 files

Documentation/virtual/kvm/api.txt +4 −0
arch/arm/include/asm/kvm_emulate.h +10 −0
arch/arm/include/asm/kvm_host.h +4 −1
arch/arm/include/asm/kvm_psci.h +23 −0
arch/arm/include/uapi/asm/kvm.h +16 −0
arch/arm/kvm/Makefile +1 −1
arch/arm/kvm/arm.c +28 −2
arch/arm/kvm/psci.c +108 −0
include/uapi/linux/kvm.h +1 −0

Documentation/virtual/kvm/api.txt+4−0

@@ -2185,6 +2185,10 @@ return ENOEXEC for that vcpu. · 2184 unmodified lines
2185	2185	Note that because some registers reflect machine topology, all vcpus
2186	2186	should be created before this ioctl is invoked.
2187	2187
	2188	+Possible features:
	2189	+ - KVM_ARM_VCPU_POWER_OFF: Starts the CPU in a power-off state.
	2190	+ Depends on KVM_CAP_ARM_PSCI.
	2191	+
2188	2192
2189	2193	4.78 KVM_GET_REG_LIST
2190	2194

arch/arm/include/asm/kvm_emulate.h+10−0

@@ -32,6 +32,11 @@ void kvm_inject_undefined(struct kvm_vcpu *vcpu); · 31 unmodified lines
32	32	void kvm_inject_dabt(struct kvm_vcpu *vcpu, unsigned long addr);
33	33	void kvm_inject_pabt(struct kvm_vcpu *vcpu, unsigned long addr);
34	34
	35	+static inline bool vcpu_mode_is_32bit(struct kvm_vcpu *vcpu)
	36	+{
	37	+ return 1;
	38	+}
	39	+
35	40	static inline u32 vcpu_pc(struct kvm_vcpu vcpu)
36	41	{
37	42	return (u32 *)&vcpu->arch.regs.usr_regs.ARM_pc;
@@ -42,6 +47,11 @@ static inline u32 vcpu_cpsr(struct kvm_vcpu vcpu) · 4 unmodified lines
42	47	return (u32 *)&vcpu->arch.regs.usr_regs.ARM_cpsr;
43	48	}
44	49
	50	+static inline void vcpu_set_thumb(struct kvm_vcpu *vcpu)
	51	+{
	52	+ *vcpu_cpsr(vcpu) \|= PSR_T_BIT;
	53	+}
	54	+
45	55	static inline bool mode_has_spsr(struct kvm_vcpu *vcpu)
46	56	{
47	57	unsigned long cpsr_mode = vcpu->arch.regs.usr_regs.ARM_cpsr & MODE_MASK;

arch/arm/include/asm/kvm_host.h+4−1

@@ -30,7 +30,7 @@ · 29 unmodified lines
30	30	#define KVM_COALESCED_MMIO_PAGE_OFFSET 1
31	31	#define KVM_HAVE_ONE_REG
32	32
33		−#define KVM_VCPU_MAX_FEATURES 0
	33	+#define KVM_VCPU_MAX_FEATURES 1
34	34
35	35	/* We don't currently support large pages. */
36	36	#define KVM_HPAGE_GFN_SHIFT(x) 0
@@ -100,6 +100,9 @@ struct kvm_vcpu_arch { · 63 unmodified lines
100	100	int last_pcpu;
101	101	cpumask_t require_dcache_flush;
102	102
	103	+ /* Don't run the guest on this vcpu */
	104	+ bool pause;
	105	+
103	106	/* IO related fields */
104	107	struct kvm_decode mmio_decode;
105	108

arch/arm/include/asm/kvm_psci.h+23−0

@@ -0,0 +1,23 @@
	1	+/*
	2	+ * Copyright (C) 2012 - ARM Ltd
	3	+ * Author: Marc Zyngier <marc.zyngier@arm.com>
	4	+ *
	5	+ * This program is free software; you can redistribute it and/or modify
	6	+ * it under the terms of the GNU General Public License version 2 as
	7	+ * published by the Free Software Foundation.
	8	+ *
	9	+ * This program is distributed in the hope that it will be useful,
	10	+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	+ * GNU General Public License for more details.
	13	+ *
	14	+ * You should have received a copy of the GNU General Public License
	15	+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
	16	+ */
	17	+
	18	+#ifndef __ARM_KVM_PSCI_H__
	19	+#define __ARM_KVM_PSCI_H__
	20	+
	21	+bool kvm_psci_call(struct kvm_vcpu *vcpu);
	22	+
	23	+#endif /* __ARM_KVM_PSCI_H__ */

arch/arm/include/uapi/asm/kvm.h+16−0

@@ -65,6 +65,8 @@ struct kvm_regs { · 64 unmodified lines
65	65	#define KVM_ARM_TARGET_CORTEX_A15 0
66	66	#define KVM_ARM_NUM_TARGETS 1
67	67
	68	+#define KVM_ARM_VCPU_POWER_OFF 0 /* CPU is started in OFF state */
	69	+
68	70	struct kvm_vcpu_init {
69	71	__u32 target;
70	72	__u32 features[7];
@@ -145,4 +147,18 @@ struct kvm_arch_memory_slot { · 74 unmodified lines
145	147	/* Highest supported SPI, from VGIC_NR_IRQS */
146	148	#define KVM_ARM_IRQ_GIC_MAX 127
147	149
	150	+/* PSCI interface */
	151	+#define KVM_PSCI_FN_BASE 0x95c1ba5e
	152	+#define KVM_PSCI_FN(n) (KVM_PSCI_FN_BASE + (n))
	153	+
	154	+#define KVM_PSCI_FN_CPU_SUSPEND KVM_PSCI_FN(0)
	155	+#define KVM_PSCI_FN_CPU_OFF KVM_PSCI_FN(1)
	156	+#define KVM_PSCI_FN_CPU_ON KVM_PSCI_FN(2)
	157	+#define KVM_PSCI_FN_MIGRATE KVM_PSCI_FN(3)
	158	+
	159	+#define KVM_PSCI_RET_SUCCESS 0
	160	+#define KVM_PSCI_RET_NI ((unsigned long)-1)
	161	+#define KVM_PSCI_RET_INVAL ((unsigned long)-2)
	162	+#define KVM_PSCI_RET_DENIED ((unsigned long)-3)
	163	+
148	164	#endif /* __ARM_KVM_H__ */

arch/arm/kvm/Makefile+1−1

@@ -18,4 +18,4 @@ kvm-arm-y = $(addprefix ../../../virt/kvm/, kvm_main.o coalesced_mmio.o) · 17 unmodified lines
18	18
19	19	obj-y += kvm-arm.o init.o interrupts.o
20	20	obj-y += arm.o guest.o mmu.o emulate.o reset.o
21		−obj-y += coproc.o coproc_a15.o mmio.o
	21	+obj-y += coproc.o coproc_a15.o mmio.o psci.o

arch/arm/kvm/arm.c+28−2

@@ -43,6 +43,7 @@ · 42 unmodified lines
43	43	#include <asm/kvm_mmu.h>
44	44	#include <asm/kvm_emulate.h>
45	45	#include <asm/kvm_coproc.h>
	46	+#include <asm/kvm_psci.h>
46	47	#include <asm/opcodes.h>
47	48
48	49	#ifdef REQUIRES_VIRT
@@ -160,6 +161,7 @@ int kvm_dev_ioctl_check_extension(long ext) · 111 unmodified lines
160	161	case KVM_CAP_SYNC_MMU:
161	162	case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
162	163	case KVM_CAP_ONE_REG:
	164	+ case KVM_CAP_ARM_PSCI:
163	165	r = 1;
164	166	break;
165	167	case KVM_CAP_COALESCED_MMIO:
@@ -443,14 +445,18 @@ static int handle_hvc(struct kvm_vcpu vcpu, struct kvm_run run) · 277 unmodified lines
443	445	trace_kvm_hvc(vcpu_pc(vcpu), vcpu_reg(vcpu, 0),
444	446	vcpu->arch.hsr & HSR_HVC_IMM_MASK);
445	447
	448	+ if (kvm_psci_call(vcpu))
	449	+ return 1;
	450	+
446	451	kvm_inject_undefined(vcpu);
447	452	return 1;
448	453	}
449	454
450	455	static int handle_smc(struct kvm_vcpu vcpu, struct kvm_run run)
451	456	{
452		− /* We don't support SMC; don't do that. */
453		− kvm_debug("smc: at %08x", *vcpu_pc(vcpu));
	457	+ if (kvm_psci_call(vcpu))
	458	+ return 1;
	459	+
454	460	kvm_inject_undefined(vcpu);
455	461	return 1;
456	462	}
@@ -589,9 +595,26 @@ static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu) · 132 unmodified lines
589	595	return 0;
590	596
591	597	vcpu->arch.has_run_once = true;
	598	+
	599	+ /*
	600	+ * Handle the "start in power-off" case by calling into the
	601	+ * PSCI code.
	602	+ */
	603	+ if (test_and_clear_bit(KVM_ARM_VCPU_POWER_OFF, vcpu->arch.features)) {
	604	+ *vcpu_reg(vcpu, 0) = KVM_PSCI_FN_CPU_OFF;
	605	+ kvm_psci_call(vcpu);
	606	+ }
	607	+
592	608	return 0;
593	609	}
594	610
	611	+static void vcpu_pause(struct kvm_vcpu *vcpu)
	612	+{
	613	+ wait_queue_head_t *wq = kvm_arch_vcpu_wq(vcpu);
	614	+
	615	+ wait_event_interruptible(*wq, !vcpu->arch.pause);
	616	+}
	617	+
595	618	/**
596	619	* kvm_arch_vcpu_ioctl_run - the main VCPU run function to execute guest code
597	620	* @vcpu: The VCPU pointer
@@ -635,6 +658,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu vcpu, struct kvm_run run) · 37 unmodified lines
635	658
636	659	update_vttbr(vcpu->kvm);
637	660
	661	+ if (vcpu->arch.pause)
	662	+ vcpu_pause(vcpu);
	663	+
638	664	local_irq_disable();
639	665
640	666	/*

arch/arm/kvm/psci.c+108−0

@@ -0,0 +1,108 @@
	1	+/*
	2	+ * Copyright (C) 2012 - ARM Ltd
	3	+ * Author: Marc Zyngier <marc.zyngier@arm.com>
	4	+ *
	5	+ * This program is free software; you can redistribute it and/or modify
	6	+ * it under the terms of the GNU General Public License version 2 as
	7	+ * published by the Free Software Foundation.
	8	+ *
	9	+ * This program is distributed in the hope that it will be useful,
	10	+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	+ * GNU General Public License for more details.
	13	+ *
	14	+ * You should have received a copy of the GNU General Public License
	15	+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
	16	+ */
	17	+
	18	+#include <linux/kvm_host.h>
	19	+#include <linux/wait.h>
	20	+
	21	+#include <asm/kvm_emulate.h>
	22	+#include <asm/kvm_psci.h>
	23	+
	24	+/*
	25	+ * This is an implementation of the Power State Coordination Interface
	26	+ * as described in ARM document number ARM DEN 0022A.
	27	+ */
	28	+
	29	+static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu)
	30	+{
	31	+ vcpu->arch.pause = true;
	32	+}
	33	+
	34	+static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
	35	+{
	36	+ struct kvm *kvm = source_vcpu->kvm;
	37	+ struct kvm_vcpu *vcpu;
	38	+ wait_queue_head_t *wq;
	39	+ unsigned long cpu_id;
	40	+ phys_addr_t target_pc;
	41	+
	42	+ cpu_id = *vcpu_reg(source_vcpu, 1);
	43	+ if (vcpu_mode_is_32bit(source_vcpu))
	44	+ cpu_id &= ~((u32) 0);
	45	+
	46	+ if (cpu_id >= atomic_read(&kvm->online_vcpus))
	47	+ return KVM_PSCI_RET_INVAL;
	48	+
	49	+ target_pc = *vcpu_reg(source_vcpu, 2);
	50	+
	51	+ vcpu = kvm_get_vcpu(kvm, cpu_id);
	52	+
	53	+ wq = kvm_arch_vcpu_wq(vcpu);
	54	+ if (!waitqueue_active(wq))
	55	+ return KVM_PSCI_RET_INVAL;
	56	+
	57	+ kvm_reset_vcpu(vcpu);
	58	+
	59	+ /* Gracefully handle Thumb2 entry point */
	60	+ if (vcpu_mode_is_32bit(vcpu) && (target_pc & 1)) {
	61	+ target_pc &= ~((phys_addr_t) 1);
	62	+ vcpu_set_thumb(vcpu);
	63	+ }
	64	+
	65	+ *vcpu_pc(vcpu) = target_pc;
	66	+ vcpu->arch.pause = false;
	67	+ smp_mb(); /* Make sure the above is visible */
	68	+
	69	+ wake_up_interruptible(wq);
	70	+
	71	+ return KVM_PSCI_RET_SUCCESS;
	72	+}
	73	+
	74	+/**
	75	+ * kvm_psci_call - handle PSCI call if r0 value is in range
	76	+ * @vcpu: Pointer to the VCPU struct
	77	+ *
	78	+ * Handle PSCI calls from guests through traps from HVC or SMC instructions.
	79	+ * The calling convention is similar to SMC calls to the secure world where
	80	+ * the function number is placed in r0 and this function returns true if the
	81	+ * function number specified in r0 is withing the PSCI range, and false
	82	+ * otherwise.
	83	+ */
	84	+bool kvm_psci_call(struct kvm_vcpu *vcpu)
	85	+{
	86	+ unsigned long psci_fn = *vcpu_reg(vcpu, 0) & ~((u32) 0);
	87	+ unsigned long val;
	88	+
	89	+ switch (psci_fn) {
	90	+ case KVM_PSCI_FN_CPU_OFF:
	91	+ kvm_psci_vcpu_off(vcpu);
	92	+ val = KVM_PSCI_RET_SUCCESS;
	93	+ break;
	94	+ case KVM_PSCI_FN_CPU_ON:
	95	+ val = kvm_psci_vcpu_on(vcpu);
	96	+ break;
	97	+ case KVM_PSCI_FN_CPU_SUSPEND:
	98	+ case KVM_PSCI_FN_MIGRATE:
	99	+ val = KVM_PSCI_RET_NI;
	100	+ break;
	101	+
	102	+ default:
	103	+ return false;
	104	+ }
	105	+
	106	+ *vcpu_reg(vcpu, 0) = val;
	107	+ return true;
	108	+}

include/uapi/linux/kvm.h+1−0

@@ -636,6 +636,7 @@ struct kvm_ppc_smmu_info { · 635 unmodified lines
636	636	#define KVM_CAP_IRQFD_RESAMPLE 82
637	637	#define KVM_CAP_PPC_BOOKE_WATCHDOG 83
638	638	#define KVM_CAP_PPC_HTAB_FD 84
	639	+#define KVM_CAP_ARM_PSCI 87
639	640
640	641	#ifdef KVM_CAP_IRQ_ROUTING
641	642

KVM: ARM: Power State Coordination Interface implementation

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