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KVM: ARM: Power State Coordination Interface implementation

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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>
This commit is contained in:
Marc Zyngier 2013-01-20 18:28:13 -05:00 committed by Christoffer Dall
parent 45e96ea6b3
commit aa024c2f35
9 changed files with 195 additions and 4 deletions
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4
Documentation/virtual/kvm/api.txt
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@ -2185,6 +2185,10 @@ return ENOEXEC for that vcpu.
Note that because some registers reflect machine topology, all vcpus
should be created before this ioctl is invoked.
Possible features:
- KVM_ARM_VCPU_POWER_OFF: Starts the CPU in a power-off state.
Depends on KVM_CAP_ARM_PSCI.
4.78 KVM_GET_REG_LIST

10
arch/arm/include/asm/kvm_emulate.h
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@ -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;

5
arch/arm/include/asm/kvm_host.h
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@ -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;

23
arch/arm/include/asm/kvm_psci.h Normal file
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@ -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__ */

16
arch/arm/include/uapi/asm/kvm.h
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@ -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__ */

2
arch/arm/kvm/Makefile
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@ -18,4 +18,4 @@ 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 guest.o mmu.o emulate.o reset.o
obj-y += coproc.o coproc_a15.o mmio.o
obj-y += coproc.o coproc_a15.o mmio.o psci.o

30
arch/arm/kvm/arm.c
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@ -43,6 +43,7 @@
#include <asm/kvm_mmu.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_coproc.h>
#include <asm/kvm_psci.h>
#include <asm/opcodes.h>
#ifdef REQUIRES_VIRT
@ -160,6 +161,7 @@ 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:
@ -443,14 +445,18 @@ static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
trace_kvm_hvc(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0),
vcpu->arch.hsr & HSR_HVC_IMM_MASK);
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 %08x", *vcpu_pc(vcpu));
if (kvm_psci_call(vcpu))
return 1;
kvm_inject_undefined(vcpu);
return 1;
}
@ -589,9 +595,26 @@ static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu)
return 0;
vcpu->arch.has_run_once = true;
/*
* Handle the "start in power-off" case by calling into the
* PSCI code.
*/
if (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);
}
return 0;
}
static void vcpu_pause(struct kvm_vcpu *vcpu)
{
wait_queue_head_t *wq = kvm_arch_vcpu_wq(vcpu);
wait_event_interruptible(*wq, !vcpu->arch.pause);
}
/**
* kvm_arch_vcpu_ioctl_run - the main VCPU run function to execute guest code
* @vcpu: The VCPU pointer
@ -635,6 +658,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
update_vttbr(vcpu->kvm);
if (vcpu->arch.pause)
vcpu_pause(vcpu);
local_irq_disable();
/*

108
arch/arm/kvm/psci.c Normal file
View File

@ -0,0 +1,108 @@
/*
* 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/>.
*/
#include <linux/kvm_host.h>
#include <linux/wait.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_psci.h>
/*
* This is an implementation of the Power State Coordination Interface
* as described in ARM document number ARM DEN 0022A.
*/
static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu)
{
vcpu->arch.pause = true;
}
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);
/* Gracefully handle Thumb2 entry point */
if (vcpu_mode_is_32bit(vcpu) && (target_pc & 1)) {
target_pc &= ~((phys_addr_t) 1);
vcpu_set_thumb(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;
}
/**
* kvm_psci_call - handle PSCI call if r0 value is in range
* @vcpu: Pointer to the VCPU struct
*
* Handle PSCI calls from guests through traps from HVC or SMC instructions.
* The calling convention is similar to SMC calls to the secure world where
* the function number is placed in r0 and this function returns true if the
* function number specified in r0 is withing the PSCI range, and false
* otherwise.
*/
bool kvm_psci_call(struct kvm_vcpu *vcpu)
{
unsigned long psci_fn = *vcpu_reg(vcpu, 0) & ~((u32) 0);
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 false;
}
*vcpu_reg(vcpu, 0) = val;
return true;
}

1
include/uapi/linux/kvm.h
View File

@ -636,6 +636,7 @@ struct kvm_ppc_smmu_info {
#define KVM_CAP_IRQFD_RESAMPLE 82
#define KVM_CAP_PPC_BOOKE_WATCHDOG 83
#define KVM_CAP_PPC_HTAB_FD 84
#define KVM_CAP_ARM_PSCI 87
#ifdef KVM_CAP_IRQ_ROUTING