From aa024c2f35a07cc32e48c5f62a5807be01c09249 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Sun, 20 Jan 2013 18:28:13 -0500 Subject: [PATCH] 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 Signed-off-by: Marc Zyngier Signed-off-by: Christoffer Dall --- Documentation/virtual/kvm/api.txt | 4 ++ arch/arm/include/asm/kvm_emulate.h | 10 +++ arch/arm/include/asm/kvm_host.h | 5 +- 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 | 30 +++++++- arch/arm/kvm/psci.c | 108 +++++++++++++++++++++++++++++ include/uapi/linux/kvm.h | 1 + 9 files changed, 195 insertions(+), 4 deletions(-) create mode 100644 arch/arm/include/asm/kvm_psci.h create mode 100644 arch/arm/kvm/psci.c diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 38066a7a74e1..c25439a58274 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -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 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 + * + * 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 . + */ + +#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__ */ diff --git a/arch/arm/kvm/Makefile b/arch/arm/kvm/Makefile index 1e45cd97a7fc..ea27987bd07f 100644 --- a/arch/arm/kvm/Makefile +++ b/arch/arm/kvm/Makefile @@ -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 diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index 8680b9ffd2ae..2d30e3afdaf9 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -43,6 +43,7 @@ #include #include #include +#include #include #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(); /* diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c new file mode 100644 index 000000000000..7ee5bb7a3667 --- /dev/null +++ b/arch/arm/kvm/psci.c @@ -0,0 +1,108 @@ +/* + * Copyright (C) 2012 - ARM Ltd + * Author: Marc Zyngier + * + * 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 . + */ + +#include +#include + +#include +#include + +/* + * 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; +} diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index dc63665e73ad..7f2360a46fc2 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -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 -- 2.25.1