From patchwork Thu Feb 24 12:48:14 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Woodhouse X-Patchwork-Id: 12758508 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3012DC4332F for ; Thu, 24 Feb 2022 12:48:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234494AbiBXMtY (ORCPT ); Thu, 24 Feb 2022 07:49:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40498 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234503AbiBXMtO (ORCPT ); Thu, 24 Feb 2022 07:49:14 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A03111D8AA7 for ; Thu, 24 Feb 2022 04:48:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Sender:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description; bh=T8JqoFzERiiU7rJ0zqZH/xSk69jUKSfVven3jJkGKQ4=; b=evNlasHy+3FzxA1QkSlWnMR/gG p+r50Owxkg2pOPqG4l4uOtrWWViAADvtIVmzegXUWFm7E5sBdO2GEWBbgxD2z9bMFUqMyN8hSO2Vt zuYiswAkSZEuMsEqZ86HDUaCGeFhSmKLb6fwX8ymwRBv+WoKZ50EcysNNsvN/jXLW37U3zxnZnCSV RPgSRWJ1e6fotv3wIqGfwyuOo3KfYz0rnb46jeEmtyIJax0JS6cWy3wJugxl6zqeGyEj89r9nxUmo s57hntfamUZ7nCfQbCDhLAPR3nXPXRs8ntCE001QVGVSCG3xwbGw/qO3vjOHnitTBVGQeEe+PTQbG M8zFnEnQ==; Received: from [2001:8b0:10b:1:85c4:81a:fb42:714d] (helo=i7.infradead.org) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1nNDXl-004lng-Un; Thu, 24 Feb 2022 12:48:26 +0000 Received: from dwoodhou by i7.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nNDXj-0000ui-LP; Thu, 24 Feb 2022 12:48:23 +0000 From: David Woodhouse To: kvm@vger.kernel.org, Paolo Bonzini Cc: Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Joao Martins , Boris Ostrovsky , Metin Kaya , Paul Durrant Subject: [PATCH v1 11/16] KVM: x86/xen: handle PV timers oneshot mode Date: Thu, 24 Feb 2022 12:48:14 +0000 Message-Id: <20220224124819.3315-12-dwmw2@infradead.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20220224124819.3315-1-dwmw2@infradead.org> References: <20220224124819.3315-1-dwmw2@infradead.org> MIME-Version: 1.0 Sender: David Woodhouse X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Joao Martins If the guest has offloaded the timer virq, handle the following hypercalls for programming the timer: VCPUOP_set_singleshot_timer VCPUOP_stop_singleshot_timer set_timer_op(timestamp_ns) The event channel corresponding to the timer virq is then used to inject events once timer deadlines are met. For now we back the PV timer with hrtimer. [ dwmw2: Add save/restore, 32-bit compat mode. ] Signed-off-by: Joao Martins Signed-off-by: David Woodhouse --- arch/x86/include/asm/kvm_host.h | 4 + arch/x86/kvm/irq.c | 11 +- arch/x86/kvm/x86.c | 3 + arch/x86/kvm/xen.c | 229 ++++++++++++++++++++++++++++++++ arch/x86/kvm/xen.h | 30 +++++ include/uapi/linux/kvm.h | 6 + 6 files changed, 281 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index dc0d76d21f7f..b0caf02d12fe 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -608,6 +608,10 @@ struct kvm_vcpu_xen { u64 runstate_times[4]; unsigned long evtchn_pending_sel; u32 vcpu_id; /* The Xen / ACPI vCPU ID */ + u32 timer_virq; + u64 timer_expires; /* In guest epoch */ + atomic_t timer_pending; + struct hrtimer timer; }; struct kvm_vcpu_arch { diff --git a/arch/x86/kvm/irq.c b/arch/x86/kvm/irq.c index 172b05343cfd..af2d26fc5458 100644 --- a/arch/x86/kvm/irq.c +++ b/arch/x86/kvm/irq.c @@ -22,10 +22,14 @@ */ int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu) { + int r = 0; + if (lapic_in_kernel(vcpu)) - return apic_has_pending_timer(vcpu); + r = apic_has_pending_timer(vcpu); + if (kvm_xen_timer_enabled(vcpu)) + r += kvm_xen_has_pending_timer(vcpu); - return 0; + return r; } EXPORT_SYMBOL(kvm_cpu_has_pending_timer); @@ -143,6 +147,8 @@ void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu) { if (lapic_in_kernel(vcpu)) kvm_inject_apic_timer_irqs(vcpu); + if (kvm_xen_timer_enabled(vcpu)) + kvm_xen_inject_timer_irqs(vcpu); } EXPORT_SYMBOL_GPL(kvm_inject_pending_timer_irqs); @@ -150,6 +156,7 @@ void __kvm_migrate_timers(struct kvm_vcpu *vcpu) { __kvm_migrate_apic_timer(vcpu); __kvm_migrate_pit_timer(vcpu); + __kvm_migrate_xen_timer(vcpu); static_call_cond(kvm_x86_migrate_timers)(vcpu); } diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 70e58fce1e29..a683a126a437 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12085,6 +12085,9 @@ static inline bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu) kvm_x86_ops.nested_ops->hv_timer_pending(vcpu)) return true; + if (kvm_xen_has_pending_timer(vcpu)) + return true; + return false; } diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c index 3663bb2caa2b..cc172ca83bbb 100644 --- a/arch/x86/kvm/xen.c +++ b/arch/x86/kvm/xen.c @@ -23,6 +23,7 @@ #include "trace.h" +static int kvm_xen_set_evtchn(struct kvm_xen_evtchn *xe, struct kvm *kvm); static int kvm_xen_setattr_evtchn(struct kvm *kvm, struct kvm_xen_hvm_attr *data); static bool kvm_xen_hcall_evtchn_send(struct kvm_vcpu *vcpu, u64 param, u64 *r); @@ -108,6 +109,84 @@ static int kvm_xen_shared_info_init(struct kvm *kvm, gfn_t gfn) return ret; } +void kvm_xen_inject_timer_irqs(struct kvm_vcpu *vcpu) +{ + if (atomic_read(&vcpu->arch.xen.timer_pending) > 0) { + struct kvm_xen_evtchn e; + + e.vcpu_id = vcpu->vcpu_id; + e.vcpu_idx = vcpu->vcpu_idx; + e.port = vcpu->arch.xen.timer_virq; + e.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL; + + kvm_xen_set_evtchn(&e, vcpu->kvm); + atomic_set(&vcpu->arch.xen.timer_pending, 0); + } +} + +static enum hrtimer_restart xen_timer_callback(struct hrtimer *timer) +{ + struct kvm_vcpu *vcpu = container_of(timer, struct kvm_vcpu, + arch.xen.timer); + struct kvm_xen_evtchn e; + + if (atomic_read(&vcpu->arch.xen.timer_pending)) + return HRTIMER_NORESTART; + + e.vcpu_id = vcpu->vcpu_id; + e.vcpu_idx = vcpu->vcpu_idx; + e.port = vcpu->arch.xen.timer_virq; + e.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL; + + if (kvm_xen_set_evtchn_fast(&e, vcpu->kvm) != -EWOULDBLOCK) + return HRTIMER_NORESTART; + + atomic_inc(&vcpu->arch.xen.timer_pending); + kvm_make_request(KVM_REQ_UNBLOCK, vcpu); + kvm_vcpu_kick(vcpu); + + return HRTIMER_NORESTART; +} + +void __kvm_migrate_xen_timer(struct kvm_vcpu *vcpu) +{ + struct hrtimer *timer; + + if (!kvm_xen_timer_enabled(vcpu)) + return; + + timer = &vcpu->arch.xen.timer; + if (hrtimer_cancel(timer)) + hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED); +} + +static void kvm_xen_start_timer(struct kvm_vcpu *vcpu, u64 guest_abs, u64 delta_ns) +{ + ktime_t ktime_now; + + atomic_set(&vcpu->arch.xen.timer_pending, 0); + vcpu->arch.xen.timer_expires = guest_abs; + + ktime_now = ktime_get(); + hrtimer_start(&vcpu->arch.xen.timer, + ktime_add_ns(ktime_now, delta_ns), + HRTIMER_MODE_ABS_PINNED); +} + +static void kvm_xen_stop_timer(struct kvm_vcpu *vcpu) +{ + hrtimer_cancel(&vcpu->arch.xen.timer); + vcpu->arch.xen.timer_expires = 0; + atomic_set(&vcpu->arch.xen.timer_pending, 0); +} + +void kvm_xen_init_timer(struct kvm_vcpu *vcpu) +{ + hrtimer_init(&vcpu->arch.xen.timer, CLOCK_MONOTONIC, + HRTIMER_MODE_ABS_PINNED); + vcpu->arch.xen.timer.function = xen_timer_callback; +} + static void kvm_xen_update_runstate(struct kvm_vcpu *v, int state) { struct kvm_vcpu_xen *vx = &v->arch.xen; @@ -617,6 +696,28 @@ int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data) } break; + case KVM_XEN_VCPU_ATTR_TYPE_TIMER: + if (data->u.timer.port) { + if (data->u.timer.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL) { + r = -EINVAL; + break; + } + vcpu->arch.xen.timer_virq = data->u.timer.port; + kvm_xen_init_timer(vcpu); + + /* Restart the timer if it's set */ + if (data->u.timer.expires_ns) + kvm_xen_start_timer(vcpu, data->u.timer.expires_ns, + data->u.timer.expires_ns - + get_kvmclock_ns(vcpu->kvm)); + } else if (kvm_xen_timer_enabled(vcpu)) { + kvm_xen_stop_timer(vcpu); + vcpu->arch.xen.timer_virq = 0; + } + + r = 0; + break; + default: break; } @@ -697,6 +798,13 @@ int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data) r = 0; break; + case KVM_XEN_VCPU_ATTR_TYPE_TIMER: + data->u.timer.port = vcpu->arch.xen.timer_virq; + data->u.timer.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL; + data->u.timer.expires_ns = vcpu->arch.xen.timer_expires; + r = 0; + break; + default: break; } @@ -832,6 +940,112 @@ static bool kvm_xen_hcall_sched_op(struct kvm_vcpu *vcpu, int cmd, u64 param, u6 return false; } +struct compat_vcpu_set_singleshot_timer { + uint64_t timeout_abs_ns; + uint32_t flags; +} __attribute__((packed)); + +static bool kvm_xen_hcall_vcpu_op(struct kvm_vcpu *vcpu, bool longmode, int cmd, + int vcpu_id, u64 param, u64 *r) +{ + struct vcpu_set_singleshot_timer oneshot; + long delta; + gpa_t gpa; + int idx; + + if (!kvm_xen_timer_enabled(vcpu)) + return false; + + switch (cmd) { + case VCPUOP_set_singleshot_timer: + if (vcpu->arch.xen.vcpu_id != vcpu_id) { + *r = -EINVAL; + return true; + } + idx = srcu_read_lock(&vcpu->kvm->srcu); + gpa = kvm_mmu_gva_to_gpa_system(vcpu, param, NULL); + srcu_read_unlock(&vcpu->kvm->srcu, idx); + + /* + * The only difference for 32-bit compat is the 4 bytes of + * padding after the interesting part of the structure. So + * for a faithful emulation of Xen we have to *try* to copy + * the padding and return -EFAULT if we can't. Otherwise we + * might as well just have copied the 12-byte 32-bit struct. + */ + BUILD_BUG_ON(offsetof(struct compat_vcpu_set_singleshot_timer, timeout_abs_ns) != + offsetof(struct vcpu_set_singleshot_timer, timeout_abs_ns)); + BUILD_BUG_ON(sizeof_field(struct compat_vcpu_set_singleshot_timer, timeout_abs_ns) != + sizeof_field(struct vcpu_set_singleshot_timer, timeout_abs_ns)); + BUILD_BUG_ON(offsetof(struct compat_vcpu_set_singleshot_timer, flags) != + offsetof(struct vcpu_set_singleshot_timer, flags)); + BUILD_BUG_ON(sizeof_field(struct compat_vcpu_set_singleshot_timer, flags) != + sizeof_field(struct vcpu_set_singleshot_timer, flags)); + + if (!gpa || + kvm_vcpu_read_guest(vcpu, gpa, &oneshot, longmode ? sizeof(oneshot) : + sizeof(struct compat_vcpu_set_singleshot_timer))) { + *r = -EFAULT; + return true; + } + + delta = oneshot.timeout_abs_ns - get_kvmclock_ns(vcpu->kvm); + if ((oneshot.flags & VCPU_SSHOTTMR_future) && delta < 0) { + *r = -ETIME; + return true; + } + + kvm_xen_start_timer(vcpu, oneshot.timeout_abs_ns, delta); + *r = 0; + return true; + + case VCPUOP_stop_singleshot_timer: + if (vcpu->arch.xen.vcpu_id != vcpu_id) { + *r = -EINVAL; + return true; + } + kvm_xen_stop_timer(vcpu); + *r = 0; + return true; + } + + return false; +} + +static bool kvm_xen_hcall_set_timer_op(struct kvm_vcpu *vcpu, uint64_t timeout, + u64 *r) +{ + if (!kvm_xen_timer_enabled(vcpu)) + return false; + + if (timeout) { + uint64_t guest_now = get_kvmclock_ns(vcpu->kvm); + long delta = timeout - guest_now; + + /* Xen has a 'Linux workaround' in do_set_timer_op() which + * checks for negative absolute timeout values (caused by + * integer overflow), and for values about 13 days in the + * future (2^50ns) which would be caused by jiffies + * overflow. For those cases, it sets the timeout 100ms in + * the future (not *too* soon, since if a guest really did + * set a long timeout on purpose we don't want to keep + * churning CPU time by waking it up). + */ + if (unlikely((int64_t)timeout < 0 || + (delta > 0 && (uint32_t) (delta >> 50) != 0))) { + delta = 100 * NSEC_PER_MSEC; + timeout = guest_now + delta; + } + + kvm_xen_start_timer(vcpu, timeout, delta); + } else { + kvm_xen_stop_timer(vcpu); + } + + *r = 0; + return true; +} + int kvm_xen_hypercall(struct kvm_vcpu *vcpu) { bool longmode; @@ -875,6 +1089,18 @@ int kvm_xen_hypercall(struct kvm_vcpu *vcpu) case __HYPERVISOR_sched_op: handled = kvm_xen_hcall_sched_op(vcpu, params[0], params[1], &r); break; + case __HYPERVISOR_vcpu_op: + handled = kvm_xen_hcall_vcpu_op(vcpu, longmode, params[0], params[1], + params[2], &r); + break; + case __HYPERVISOR_set_timer_op: { + u64 timeout = params[0]; + /* In 32-bit mode, the 64-bit timeout is in two 32-bit params. */ + if (!longmode) + timeout |= params[1] << 32; + handled = kvm_xen_hcall_set_timer_op(vcpu, timeout, &r); + break; + } default: break; } @@ -1383,6 +1609,9 @@ void kvm_xen_init_vcpu(struct kvm_vcpu *vcpu) void kvm_xen_destroy_vcpu(struct kvm_vcpu *vcpu) { + if (kvm_xen_timer_enabled(vcpu)) + kvm_xen_stop_timer(vcpu); + kvm_gfn_to_pfn_cache_destroy(vcpu->kvm, &vcpu->arch.xen.runstate_cache); vcpu->arch.xen.vcpu_info_cache.dirty = false; diff --git a/arch/x86/kvm/xen.h b/arch/x86/kvm/xen.h index 54d587aae85b..616fe751c8fc 100644 --- a/arch/x86/kvm/xen.h +++ b/arch/x86/kvm/xen.h @@ -62,6 +62,21 @@ static inline bool kvm_xen_has_pending_events(struct kvm_vcpu *vcpu) vcpu->arch.xen.evtchn_pending_sel; } +static inline bool kvm_xen_timer_enabled(struct kvm_vcpu *vcpu) +{ + return !!vcpu->arch.xen.timer_virq; +} + +static inline int kvm_xen_has_pending_timer(struct kvm_vcpu *vcpu) +{ + if (kvm_xen_hypercall_enabled(vcpu->kvm) && kvm_xen_timer_enabled(vcpu)) + return atomic_read(&vcpu->arch.xen.timer_pending); + + return 0; +} + +void __kvm_migrate_xen_timer(struct kvm_vcpu *vcpu); +void kvm_xen_inject_timer_irqs(struct kvm_vcpu *vcpu); #else static inline int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data) { @@ -104,6 +119,21 @@ static inline void kvm_xen_inject_pending_events(struct kvm_vcpu *vcpu) } static inline bool kvm_xen_has_pending_events(struct kvm_vcpu *vcpu) + +static inline void __kvm_migrate_xen_timer(struct kvm_vcpu *vcpu) +{ +} + +static inline int kvm_xen_has_pending_timer(struct kvm_vcpu *vcpu) +{ + return 0; +} + +static inline void kvm_xen_inject_timer_irqs(struct kvm_vcpu *vcpu) +{ +} + +static inline bool kvm_xen_timer_enabled(struct kvm_vcpu *vcpu) { return false; } diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 2b01e026f06c..47d6b0f6d5ab 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1737,6 +1737,11 @@ struct kvm_xen_vcpu_attr { __u64 time_offline; } runstate; __u32 vcpu_id; + struct { + __u32 port; + __u32 priority; + __u64 expires_ns; + } timer; } u; }; @@ -1749,6 +1754,7 @@ struct kvm_xen_vcpu_attr { #define KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST 0x5 /* Available with KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_EVTCHN_SEND */ #define KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID 0x6 +#define KVM_XEN_VCPU_ATTR_TYPE_TIMER 0x7 /* Secure Encrypted Virtualization command */ enum sev_cmd_id {