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[35.228.58.138]) by smtp.gmail.com with ESMTPSA id a10-20020a194f4a000000b004793605e59dsm2116674lfk.245.2022.06.09.04.04.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Jun 2022 04:04:16 -0700 (PDT) From: Grzegorz Jaszczyk To: linux-kernel@vger.kernel.org Cc: jaz@semihalf.com, dmy@semihalf.com, Zide Chen , Peter Fang , Paolo Bonzini , Jonathan Corbet , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)), "H. Peter Anvin" , "Rafael J. Wysocki" , Len Brown , Pavel Machek , Steve Rutherford , Ashish Kalra , Mario Limonciello , Pratik Vishwakarma , Hans de Goede , Alex Deucher , Sachi King , Arnaldo Carvalho de Melo , Jing Liu , Fabiano Rosas , Wei Wang , Nicholas Piggin , kvm@vger.kernel.org (open list:KERNEL VIRTUAL MACHINE (KVM)), linux-doc@vger.kernel.org (open list:DOCUMENTATION), linux-acpi@vger.kernel.org (open list:ACPI), linux-pm@vger.kernel.org (open list:HIBERNATION (aka Software Suspend, aka swsusp)) Subject: [PATCH 2/2] KVM: x86: notify user space about guest entering s2idle Date: Thu, 9 Jun 2022 11:03:28 +0000 Message-Id: <20220609110337.1238762-3-jaz@semihalf.com> X-Mailer: git-send-email 2.36.1.476.g0c4daa206d-goog In-Reply-To: <20220609110337.1238762-1-jaz@semihalf.com> References: <20220609110337.1238762-1-jaz@semihalf.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org From: Zide Chen Upon exiting to user space, the kvm_run structure contains system_event with type KVM_SYSTEM_EVENT_S2IDLE to notify about guest entering s2idle suspend state. Userspace can choose to: - ignore it - start the suspend flow in host (if notified from privileged VM, capable of suspending the host machine) - take advantage of this event to make sure that the VM is suspended The last one is especially useful for cases where some devices are pass-through to the VM and to perform full system suspension, the guest needs to finish with it's own suspension process first (e.g. calling suspend hooks for given driver/subsystem which resides on the guest). In such case host user-space power daemon (e.g. powerd) could first notify VMM about suspension imminent. Next the VMM could trigger suspension process on the guest VM and block till receiving KVM_SYSTEM_EVENT_S2IDLE notification, after which the suspension of the host can continue. Additionally to not introduce regression on existing VMM which doesn't support KVM_SYSTEM_EVENT_S2IDLE exits, allow to enable it through KVM_CAP_X86_SYSTEM_S2IDLE VM capability. Co-developed-by: Peter Fang Signed-off-by: Peter Fang Signed-off-by: Zide Chen Co-developed-by: Grzegorz Jaszczyk Signed-off-by: Grzegorz Jaszczyk --- Documentation/virt/kvm/api.rst | 21 +++++++++++++++++++++ arch/x86/include/asm/kvm_host.h | 2 ++ arch/x86/kvm/x86.c | 15 +++++++++++++++ include/uapi/linux/kvm.h | 2 ++ tools/include/uapi/linux/kvm.h | 1 + 5 files changed, 41 insertions(+) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 11e00a46c610..670dada87f50 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6146,6 +6146,8 @@ should put the acknowledged interrupt vector into the 'epr' field. #define KVM_SYSTEM_EVENT_WAKEUP 4 #define KVM_SYSTEM_EVENT_SUSPEND 5 #define KVM_SYSTEM_EVENT_SEV_TERM 6 + #define KVM_SYSTEM_EVENT_S2IDLE 7 + __u32 type; __u32 ndata; __u64 data[16]; @@ -6177,6 +6179,15 @@ Valid values for 'type' are: marking the exiting vCPU as runnable, or deny it and call KVM_RUN again. - KVM_SYSTEM_EVENT_SUSPEND -- the guest has requested a suspension of the VM. + - KVM_SYSTEM_EVENT_S2IDLE -- the guest has notified about entering s2idle + state. Userspace can choose to: + - ignore it + - start the suspend flow in host (if notified from a privileged VM, capable + of suspending the host machine) + - take advantage of this event to make sure that the VM is suspended - used + for full system suspension, where the host waits for guest suspension + before continues with it's own, host suspension process. + This is available on x86 only. If KVM_CAP_SYSTEM_EVENT_DATA is present, the 'data' field can contain architecture specific information for the system-level event. Only @@ -7956,6 +7967,16 @@ should adjust CPUID leaf 0xA to reflect that the PMU is disabled. When enabled, KVM will exit to userspace with KVM_EXIT_SYSTEM_EVENT of type KVM_SYSTEM_EVENT_SUSPEND to process the guest suspend request. +8.37 KVM_CAP_X86_SYSTEM_S2IDLE +------------------------------- + +:Capability: KVM_CAP_X86_SYSTEM_S2IDLE +:Architectures: x86 +:Type: vm + +When enabled, KVM will exit to userspace with KVM_EXIT_SYSTEM_EVENT of +type KVM_SYSTEM_EVENT_S2IDLE to process the guest s2idle notification. + 9. Known KVM API problems ========================= diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 959d66b9be94..85966da56c75 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -105,6 +105,7 @@ KVM_ARCH_REQ_FLAGS(30, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) #define KVM_REQ_MMU_FREE_OBSOLETE_ROOTS \ KVM_ARCH_REQ_FLAGS(31, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) +#define KVM_REQ_HV_S2IDLE KVM_ARCH_REQ(32) #define CR0_RESERVED_BITS \ (~(unsigned long)(X86_CR0_PE | X86_CR0_MP | X86_CR0_EM | X86_CR0_TS \ @@ -1160,6 +1161,7 @@ struct kvm_arch { bool bus_lock_detection_enabled; bool enable_pmu; + bool s2idle_notification; /* * If exit_on_emulation_error is set, and the in-kernel instruction * emulator fails to emulate an instruction, allow userspace diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 6ed4bd6e762b..651ebac025c1 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4291,6 +4291,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_SYS_ATTRIBUTES: case KVM_CAP_VAPIC: case KVM_CAP_ENABLE_CAP: + case KVM_CAP_X86_SYSTEM_S2IDLE: r = 1; break; case KVM_CAP_EXIT_HYPERCALL: @@ -6084,6 +6085,10 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, } mutex_unlock(&kvm->lock); break; + case KVM_CAP_X86_SYSTEM_S2IDLE: + kvm->arch.s2idle_notification = true; + r = 0; + break; default: r = -EINVAL; break; @@ -9307,6 +9312,10 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) return 0; } case KVM_HC_SYSTEM_S2IDLE: + if (!vcpu->kvm->arch.s2idle_notification) + break; + + kvm_make_request(KVM_REQ_HV_S2IDLE, vcpu); ret = 0; break; default: @@ -10114,6 +10123,12 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) r = 0; goto out; } + if (kvm_check_request(KVM_REQ_HV_S2IDLE, vcpu)) { + vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT; + vcpu->run->system_event.type = KVM_SYSTEM_EVENT_S2IDLE; + r = 0; + goto out; + } /* * KVM_REQ_HV_STIMER has to be processed after diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 5088bd9f1922..dd71ccf8fce4 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -447,6 +447,7 @@ struct kvm_run { #define KVM_SYSTEM_EVENT_WAKEUP 4 #define KVM_SYSTEM_EVENT_SUSPEND 5 #define KVM_SYSTEM_EVENT_SEV_TERM 6 +#define KVM_SYSTEM_EVENT_S2IDLE 7 __u32 type; __u32 ndata; union { @@ -1157,6 +1158,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_VM_TSC_CONTROL 214 #define KVM_CAP_SYSTEM_EVENT_DATA 215 #define KVM_CAP_ARM_SYSTEM_SUSPEND 216 +#define KVM_CAP_X86_SYSTEM_S2IDLE 217 #ifdef KVM_CAP_IRQ_ROUTING diff --git a/tools/include/uapi/linux/kvm.h b/tools/include/uapi/linux/kvm.h index 6a184d260c7f..f8db91439c41 100644 --- a/tools/include/uapi/linux/kvm.h +++ b/tools/include/uapi/linux/kvm.h @@ -444,6 +444,7 @@ 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_S2IDLE 7 __u32 type; __u32 ndata; union {