From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 94443C3A59D for ; Thu, 22 Aug 2019 10:40:06 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 2238E205ED for ; Thu, 22 Aug 2019 10:40:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2238E205ED Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvmarm-bounces@lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id ABCCE4A5C7; Thu, 22 Aug 2019 06:40:05 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id s8YAk-kIkAsW; Thu, 22 Aug 2019 06:40:04 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 369C94A59A; Thu, 22 Aug 2019 06:40:04 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 590C84A596 for ; Thu, 22 Aug 2019 06:40:02 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id z3a5FjqBOkjE for ; Thu, 22 Aug 2019 06:40:00 -0400 (EDT) Received: from huawei.com (szxga06-in.huawei.com [45.249.212.32]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id E8B2D4A534 for ; Thu, 22 Aug 2019 06:39:59 -0400 (EDT) Received: from DGGEMS406-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id E52FE60E25E38C112446; Thu, 22 Aug 2019 18:39:56 +0800 (CST) Received: from localhost (10.202.226.61) by DGGEMS406-HUB.china.huawei.com (10.3.19.206) with Microsoft SMTP Server id 14.3.439.0; Thu, 22 Aug 2019 18:39:55 +0800 Date: Thu, 22 Aug 2019 11:39:42 +0100 From: Jonathan Cameron To: Steven Price Subject: Re: [PATCH v3 05/10] KVM: arm64: Support stolen time reporting via shared structure Message-ID: <20190822113942.0000701f@huawei.com> In-Reply-To: <20190821153656.33429-6-steven.price@arm.com> References: <20190821153656.33429-1-steven.price@arm.com> <20190821153656.33429-6-steven.price@arm.com> Organization: Huawei X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; i686-w64-mingw32) MIME-Version: 1.0 X-Originating-IP: [10.202.226.61] X-CFilter-Loop: Reflected Cc: kvm@vger.kernel.org, Marc Zyngier , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Russell King , Catalin Marinas , Paolo Bonzini , Will Deacon , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On Wed, 21 Aug 2019 16:36:51 +0100 Steven Price wrote: > Implement the service call for configuring a shared structure between a > VCPU and the hypervisor in which the hypervisor can write the time > stolen from the VCPU's execution time by other tasks on the host. > > The hypervisor allocates memory which is placed at an IPA chosen by user > space. The hypervisor then updates the shared structure using > kvm_put_guest() to ensure single copy atomicity of the 64-bit value > reporting the stolen time in nanoseconds. > > Whenever stolen time is enabled by the guest, the stolen time counter is > reset. > > The stolen time itself is retrieved from the sched_info structure > maintained by the Linux scheduler code. We enable SCHEDSTATS when > selecting KVM Kconfig to ensure this value is meaningful. > > Signed-off-by: Steven Price One totally trivial comment inline... Feel free to ignore :) > --- > arch/arm/include/asm/kvm_host.h | 20 +++++++++ > arch/arm64/include/asm/kvm_host.h | 25 +++++++++++- > arch/arm64/kvm/Kconfig | 1 + > include/linux/kvm_types.h | 2 + > virt/kvm/arm/arm.c | 10 +++++ > virt/kvm/arm/hypercalls.c | 3 ++ > virt/kvm/arm/pvtime.c | 67 +++++++++++++++++++++++++++++++ > 7 files changed, 127 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h > index 369b5d2d54bf..47d2ced99421 100644 > --- a/arch/arm/include/asm/kvm_host.h > +++ b/arch/arm/include/asm/kvm_host.h > @@ -39,6 +39,7 @@ > KVM_ARCH_REQ_FLAGS(0, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) > #define KVM_REQ_IRQ_PENDING KVM_ARCH_REQ(1) > #define KVM_REQ_VCPU_RESET KVM_ARCH_REQ(2) > +#define KVM_REQ_RECORD_STEAL KVM_ARCH_REQ(3) > > DECLARE_STATIC_KEY_FALSE(userspace_irqchip_in_use); > > @@ -329,6 +330,25 @@ static inline int kvm_hypercall_pv_features(struct kvm_vcpu *vcpu) > return SMCCC_RET_NOT_SUPPORTED; > } > > +static inline int kvm_hypercall_stolen_time(struct kvm_vcpu *vcpu) > +{ > + return SMCCC_RET_NOT_SUPPORTED; > +} > + > +static inline int kvm_update_stolen_time(struct kvm_vcpu *vcpu, bool init) > +{ > + return -ENOTSUPP; > +} > + > +static inline void kvm_pvtime_init_vm(struct kvm_arch *kvm_arch) > +{ > +} > + > +static inline bool kvm_is_pvtime_enabled(struct kvm_arch *kvm_arch) > +{ > + return false; > +} > + > void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot); > > struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr); > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index 583b3639062a..b6fa7beffd8a 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -44,6 +44,7 @@ > KVM_ARCH_REQ_FLAGS(0, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) > #define KVM_REQ_IRQ_PENDING KVM_ARCH_REQ(1) > #define KVM_REQ_VCPU_RESET KVM_ARCH_REQ(2) > +#define KVM_REQ_RECORD_STEAL KVM_ARCH_REQ(3) > > DECLARE_STATIC_KEY_FALSE(userspace_irqchip_in_use); > > @@ -83,6 +84,11 @@ struct kvm_arch { > > /* Mandated version of PSCI */ > u32 psci_version; > + > + struct kvm_arch_pvtime { > + gpa_t st_base; > + u64 st_size; > + } pvtime; > }; > > #define KVM_NR_MEM_OBJS 40 > @@ -338,8 +344,13 @@ struct kvm_vcpu_arch { > /* True when deferrable sysregs are loaded on the physical CPU, > * see kvm_vcpu_load_sysregs and kvm_vcpu_put_sysregs. */ > bool sysregs_loaded_on_cpu; > -}; > > + /* Guest PV state */ > + struct { > + u64 steal; > + u64 last_steal; > + } steal; > +}; > /* Pointer to the vcpu's SVE FFR for sve_{save,load}_state() */ > #define vcpu_sve_pffr(vcpu) ((void *)((char *)((vcpu)->arch.sve_state) + \ > sve_ffr_offset((vcpu)->arch.sve_max_vl))) > @@ -479,6 +490,18 @@ int kvm_perf_init(void); > int kvm_perf_teardown(void); > > int kvm_hypercall_pv_features(struct kvm_vcpu *vcpu); > +int kvm_hypercall_stolen_time(struct kvm_vcpu *vcpu); > +int kvm_update_stolen_time(struct kvm_vcpu *vcpu, bool init); > + > +static inline void kvm_pvtime_init_vm(struct kvm_arch *kvm_arch) > +{ > + kvm_arch->pvtime.st_base = GPA_INVALID; > +} > + > +static inline bool kvm_is_pvtime_enabled(struct kvm_arch *kvm_arch) > +{ > + return (kvm_arch->pvtime.st_base != GPA_INVALID); > +} > > void kvm_set_sei_esr(struct kvm_vcpu *vcpu, u64 syndrome); > > diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig > index a67121d419a2..d8b88e40d223 100644 > --- a/arch/arm64/kvm/Kconfig > +++ b/arch/arm64/kvm/Kconfig > @@ -39,6 +39,7 @@ config KVM > select IRQ_BYPASS_MANAGER > select HAVE_KVM_IRQ_BYPASS > select HAVE_KVM_VCPU_RUN_PID_CHANGE > + select SCHEDSTATS > ---help--- > Support hosting virtualized guest machines. > We don't support KVM with 16K page tables yet, due to the multiple > diff --git a/include/linux/kvm_types.h b/include/linux/kvm_types.h > index bde5374ae021..1c88e69db3d9 100644 > --- a/include/linux/kvm_types.h > +++ b/include/linux/kvm_types.h > @@ -35,6 +35,8 @@ typedef unsigned long gva_t; > typedef u64 gpa_t; > typedef u64 gfn_t; > > +#define GPA_INVALID (~(gpa_t)0) > + > typedef unsigned long hva_t; > typedef u64 hpa_t; > typedef u64 hfn_t; > diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c > index 35a069815baf..5e8343e2dd62 100644 > --- a/virt/kvm/arm/arm.c > +++ b/virt/kvm/arm/arm.c > @@ -40,6 +40,10 @@ > #include > #include > > +#include > +#include > +#include > + > #ifdef REQUIRES_VIRT > __asm__(".arch_extension virt"); > #endif > @@ -135,6 +139,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) > kvm->arch.max_vcpus = vgic_present ? > kvm_vgic_get_max_vcpus() : KVM_MAX_VCPUS; > > + kvm_pvtime_init_vm(&kvm->arch); > return ret; > out_free_stage2_pgd: > kvm_free_stage2_pgd(kvm); > @@ -379,6 +384,8 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) > kvm_vcpu_load_sysregs(vcpu); > kvm_arch_vcpu_load_fp(vcpu); > kvm_vcpu_pmu_restore_guest(vcpu); > + if (kvm_is_pvtime_enabled(&vcpu->kvm->arch)) > + kvm_make_request(KVM_REQ_RECORD_STEAL, vcpu); > > if (single_task_running()) > vcpu_clear_wfe_traps(vcpu); > @@ -644,6 +651,9 @@ static void check_vcpu_requests(struct kvm_vcpu *vcpu) > * that a VCPU sees new virtual interrupts. > */ > kvm_check_request(KVM_REQ_IRQ_PENDING, vcpu); > + > + if (kvm_check_request(KVM_REQ_RECORD_STEAL, vcpu)) > + kvm_update_stolen_time(vcpu, false); > } > } > > diff --git a/virt/kvm/arm/hypercalls.c b/virt/kvm/arm/hypercalls.c > index 63ae629c466a..ac678eabf15f 100644 > --- a/virt/kvm/arm/hypercalls.c > +++ b/virt/kvm/arm/hypercalls.c > @@ -56,6 +56,9 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu) > case ARM_SMCCC_HV_PV_FEATURES: > val = kvm_hypercall_pv_features(vcpu); > break; > + case ARM_SMCCC_HV_PV_TIME_ST: > + val = kvm_hypercall_stolen_time(vcpu); > + break; > default: > return kvm_psci_call(vcpu); > } > diff --git a/virt/kvm/arm/pvtime.c b/virt/kvm/arm/pvtime.c > index 6201d71cb1f8..28603689f6e0 100644 > --- a/virt/kvm/arm/pvtime.c > +++ b/virt/kvm/arm/pvtime.c > @@ -3,8 +3,51 @@ > > #include > > +#include > + > #include > > +int kvm_update_stolen_time(struct kvm_vcpu *vcpu, bool init) > +{ > + struct kvm *kvm = vcpu->kvm; > + struct kvm_arch_pvtime *pvtime = &kvm->arch.pvtime; > + u64 steal; > + u64 steal_le; > + u64 offset; > + int idx; > + const int stride = sizeof(struct pvclock_vcpu_stolen_time); > + > + if (pvtime->st_base == GPA_INVALID) > + return -ENOTSUPP; > + > + /* Let's do the local bookkeeping */ > + steal = vcpu->arch.steal.steal; > + steal += current->sched_info.run_delay - vcpu->arch.steal.last_steal; > + vcpu->arch.steal.last_steal = current->sched_info.run_delay; > + vcpu->arch.steal.steal = steal; > + > + offset = stride * kvm_vcpu_get_idx(vcpu); > + > + if (unlikely(offset + stride > pvtime->st_size)) > + return -EINVAL; > + > + steal_le = cpu_to_le64(steal); > + idx = srcu_read_lock(&kvm->srcu); > + if (init) { > + struct pvclock_vcpu_stolen_time init_values = { > + .revision = 0, > + .attributes = 0 > + }; > + kvm_write_guest(kvm, pvtime->st_base + offset, &init_values, > + sizeof(init_values)); > + } > + offset += offsetof(struct pvclock_vcpu_stolen_time, stolen_time); > + kvm_put_guest(kvm, pvtime->st_base + offset, steal_le, u64); > + srcu_read_unlock(&kvm->srcu, idx); > + > + return 0; > +} > + > int kvm_hypercall_pv_features(struct kvm_vcpu *vcpu) > { > u32 feature = smccc_get_arg1(vcpu); > @@ -12,6 +55,7 @@ int kvm_hypercall_pv_features(struct kvm_vcpu *vcpu) > > switch (feature) { > case ARM_SMCCC_HV_PV_FEATURES: > + case ARM_SMCCC_HV_PV_TIME_ST: > val = SMCCC_RET_SUCCESS; > break; > } > @@ -19,3 +63,26 @@ int kvm_hypercall_pv_features(struct kvm_vcpu *vcpu) > return val; > } > > +int kvm_hypercall_stolen_time(struct kvm_vcpu *vcpu) > +{ > + u64 ret; > + int err; > + > + /* > + * Start counting stolen time from the time the guest requests > + * the feature enabled. > + */ > + vcpu->arch.steal.steal = 0; > + vcpu->arch.steal.last_steal = current->sched_info.run_delay; > + > + err = kvm_update_stolen_time(vcpu, true); > + > + if (err) > + ret = SMCCC_RET_NOT_SUPPORTED; Trivial by why not return SMCCC_RET_NOT_SUPPORTED; return vcpu->kvm->arch.pvtime.st_base + ... Drops the indentation a bit and puts the error handling out of line which is slightly nicer to read (to my eyes). > + else > + ret = vcpu->kvm->arch.pvtime.st_base + > + (sizeof(struct pvclock_vcpu_stolen_time) * > + kvm_vcpu_get_idx(vcpu)); > + > + return ret; > +} _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm