ARM DEN0022D 5.19 "SYSTEM_SUSPEND" describes a PSCI call that may be used to request a system be suspended. This is optional for PSCI v1.0 and to date KVM has elected to not implement the call. However, a VMM/operator may wish to provide their guests with the ability to suspend/resume, necessitating this PSCI call.
Implement support for SYSTEM_SUSPEND according to the prescribed behavior in the specification. Add a new system event exit type, KVM_SYSTEM_EVENT_SUSPEND, to notify userspace when a VM has requested a system suspend. Make KVM_MP_STATE_HALTED a valid state on arm64. Userspace can set this to request an in-kernel emulation of the suspend. Signed-off-by: Oliver Upton <[email protected]> --- Documentation/virt/kvm/api.rst | 6 ++++ arch/arm64/include/asm/kvm_host.h | 3 ++ arch/arm64/kvm/arm.c | 8 +++++ arch/arm64/kvm/psci.c | 60 +++++++++++++++++++++++++++++++ include/uapi/linux/kvm.h | 2 ++ 5 files changed, 79 insertions(+) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index a6729c8cf063..361a57061b8f 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -5656,6 +5656,7 @@ should put the acknowledged interrupt vector into the 'epr' field. #define KVM_SYSTEM_EVENT_SHUTDOWN 1 #define KVM_SYSTEM_EVENT_RESET 2 #define KVM_SYSTEM_EVENT_CRASH 3 + #define KVM_SYSTEM_EVENT_SUSPEND 4 __u32 type; __u64 flags; } system_event; @@ -5680,6 +5681,11 @@ Valid values for 'type' are: has requested a crash condition maintenance. Userspace can choose to ignore the request, or to gather VM memory core dump and/or reset/shutdown of the VM. + - KVM_SYSTEM_EVENT_SUSPEND -- the guest has requested that the VM + suspends. Userspace is not obliged to honor this, and may call KVM_RUN + again. Doing so will cause the guest to resume at its requested entry + point. For ARM64, userspace can request in-kernel suspend emulation + by setting the vCPU's MP state to KVM_MP_STATE_HALTED. :: diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 1beda1189a15..441eb6fa7adc 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -137,6 +137,9 @@ struct kvm_arch { /* Memory Tagging Extension enabled for the guest */ bool mte_enabled; + + /* PSCI SYSTEM_SUSPEND call enabled for the guest */ + bool suspend_enabled; }; struct kvm_vcpu_fault_info { diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index f1a375648e25..d875d3bcf3c5 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -101,6 +101,10 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, } mutex_unlock(&kvm->lock); break; + case KVM_CAP_ARM_SYSTEM_SUSPEND: + r = 0; + kvm->arch.suspend_enabled = true; + break; default: r = -EINVAL; break; @@ -215,6 +219,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_SET_GUEST_DEBUG: case KVM_CAP_VCPU_ATTRIBUTES: case KVM_CAP_PTP_KVM: + case KVM_CAP_ARM_SYSTEM_SUSPEND: r = 1; break; case KVM_CAP_SET_GUEST_DEBUG2: @@ -470,6 +475,9 @@ int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu, int ret = 0; switch (mp_state->mp_state) { + case KVM_MP_STATE_HALTED: + kvm_make_request(KVM_REQ_SUSPEND, vcpu); + fallthrough; case KVM_MP_STATE_RUNNABLE: vcpu->arch.power_off = false; break; diff --git a/arch/arm64/kvm/psci.c b/arch/arm64/kvm/psci.c index d453666ddb83..cf869f1f8615 100644 --- a/arch/arm64/kvm/psci.c +++ b/arch/arm64/kvm/psci.c @@ -203,6 +203,46 @@ static void kvm_psci_system_reset(struct kvm_vcpu *vcpu) kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET); } +static int kvm_psci_system_suspend(struct kvm_vcpu *vcpu) +{ + unsigned long entry_addr, context_id; + struct kvm *kvm = vcpu->kvm; + unsigned long psci_ret = 0; + struct kvm_vcpu *tmp; + int ret = 0; + int i; + + /* + * The SYSTEM_SUSPEND PSCI call requires that all vCPUs (except the + * calling vCPU) be in an OFF state, as determined by the + * implementation. + * + * See ARM DEN0022D, 5.19 "SYSTEM_SUSPEND" for more details. + */ + mutex_lock(&kvm->lock); + kvm_for_each_vcpu(i, tmp, kvm) { + if (tmp != vcpu && !tmp->arch.power_off) { + psci_ret = PSCI_RET_DENIED; + ret = 1; + goto out; + } + } + + entry_addr = smccc_get_arg1(vcpu); + context_id = smccc_get_arg2(vcpu); + + kvm_psci_vcpu_request_reset(vcpu, entry_addr, context_id, + kvm_vcpu_is_be(vcpu)); + + memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event)); + vcpu->run->system_event.type = KVM_SYSTEM_EVENT_SUSPEND; + vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT; +out: + mutex_unlock(&kvm->lock); + smccc_set_retval(vcpu, psci_ret, 0, 0, 0); + return ret; +} + static void kvm_psci_narrow_to_32bit(struct kvm_vcpu *vcpu) { int i; @@ -223,6 +263,14 @@ static unsigned long kvm_psci_check_allowed_function(struct kvm_vcpu *vcpu, u32 if ((fn & PSCI_0_2_64BIT) && vcpu_mode_is_32bit(vcpu)) return PSCI_RET_NOT_SUPPORTED; + switch (fn) { + case PSCI_1_0_FN_SYSTEM_SUSPEND: + case PSCI_1_0_FN64_SYSTEM_SUSPEND: + if (!vcpu->kvm->arch.suspend_enabled) + return PSCI_RET_NOT_SUPPORTED; + break; + } + return 0; } @@ -316,6 +364,10 @@ static int kvm_psci_1_0_call(struct kvm_vcpu *vcpu) unsigned long val; int ret = 1; + val = kvm_psci_check_allowed_function(vcpu, psci_fn); + if (val) + goto out; + switch(psci_fn) { case PSCI_0_2_FN_PSCI_VERSION: val = KVM_ARM_PSCI_1_0; @@ -339,6 +391,8 @@ static int kvm_psci_1_0_call(struct kvm_vcpu *vcpu) case PSCI_0_2_FN_SYSTEM_OFF: case PSCI_0_2_FN_SYSTEM_RESET: case PSCI_1_0_FN_PSCI_FEATURES: + case PSCI_1_0_FN_SYSTEM_SUSPEND: + case PSCI_1_0_FN64_SYSTEM_SUSPEND: case ARM_SMCCC_VERSION_FUNC_ID: val = 0; break; @@ -347,10 +401,16 @@ static int kvm_psci_1_0_call(struct kvm_vcpu *vcpu) break; } break; + case PSCI_1_0_FN_SYSTEM_SUSPEND: + kvm_psci_narrow_to_32bit(vcpu); + fallthrough; + case PSCI_1_0_FN64_SYSTEM_SUSPEND: + return kvm_psci_system_suspend(vcpu); default: return kvm_psci_0_2_call(vcpu); } +out: smccc_set_retval(vcpu, val, 0, 0, 0); return ret; } diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index a067410ebea5..052b0e717b08 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -433,6 +433,7 @@ struct kvm_run { #define KVM_SYSTEM_EVENT_SHUTDOWN 1 #define KVM_SYSTEM_EVENT_RESET 2 #define KVM_SYSTEM_EVENT_CRASH 3 +#define KVM_SYSTEM_EVENT_SUSPEND 4 __u32 type; __u64 flags; } system_event; @@ -1112,6 +1113,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_BINARY_STATS_FD 203 #define KVM_CAP_EXIT_ON_EMULATION_FAILURE 204 #define KVM_CAP_ARM_MTE 205 +#define KVM_CAP_ARM_SYSTEM_SUSPEND 206 #ifdef KVM_CAP_IRQ_ROUTING -- 2.33.0.685.g46640cef36-goog _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
