From patchwork Sat Oct 9 02:11:57 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 12546875 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 314C0C433FE for ; Sat, 9 Oct 2021 02:12:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1BFB861040 for ; Sat, 9 Oct 2021 02:12:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244217AbhJICOv (ORCPT ); Fri, 8 Oct 2021 22:14:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38202 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244197AbhJICOt (ORCPT ); Fri, 8 Oct 2021 22:14:49 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 99A9BC061762 for ; Fri, 8 Oct 2021 19:12:52 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id z2-20020a254c02000000b005b68ef4fe24so15041461yba.11 for ; Fri, 08 Oct 2021 19:12:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=reply-to:date:in-reply-to:message-id:mime-version:references :subject:from:to:cc; bh=cmY3ciYgK0Pw7Nc3yQ2tKxt4RfIVgRouhF9jfsbApsU=; b=QbQVaw+LEXAnvKqqBqFc88s4xq502vqu1GE3XpXsagKgQF+sSH5oy9ZN3Riurg0uam NboPaoBoD+NTvzrr76ut0oSCAr/dobocjfxXDCgfKREM1WgGlcHv/XKBbx+8XlSywjl9 v6gbyQ/DSMA6ibdL//jX5ac88VgPO68Yar5tSoyOjvQU7DWuLyOGlTMs1EcHp6GBd7t8 zDaqFcWWP1eS2XcbCz8YiWyZQMO7D8kVYM83EyYLTsNWw/FWNJEOnWDm+n66w3yiKT4b k4mJC2lWsO+wgHdIF9UIkXA7mXBDmZvdXGiRS4k0umncgko4hmVixQMSV1g0v0Xm3Xav bXww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:reply-to:date:in-reply-to:message-id :mime-version:references:subject:from:to:cc; bh=cmY3ciYgK0Pw7Nc3yQ2tKxt4RfIVgRouhF9jfsbApsU=; b=53EKKkEh0X1qMKmEi96sVLRPN8vn1KZR/R1/SEGeRvgo4hRkwgYKTueaWb6Dt6lZtE KzH02IE2+sfS0wTmM49PhRYa6M9fhVlG1wDpt1ZKzcAPiar3jTGvxqYVnylD6V+3ybHM MYmIV8CiNxkJjqgyilhOXnJ6TnU3lg5DSMaUB+eU0sBFGatGb9OoLuBSBd22fRN3HMRW VhPyHzGKhnxLFkW2nbp0tuCSeEZto8CWUEwsXs7qh/0IcKHOIZ5UUmCmfyE+wITkyRT6 XxAeP1hICO3dPf0KoddnU7kQNGXXc32cgQs4JGiw6zM7CY7K5sd3s/ECb/kuTIaK3byO Dlnw== X-Gm-Message-State: AOAM5302hrVl+Tz5NktKizledKHzfZXcIcddQqBWFkET1lyEMEdL10PB Q2DibpYEHJH+lvk3sABrhdMAvp2SoJo= X-Google-Smtp-Source: ABdhPJxDfkHFA9j3YHwNecv1+8g7k+RRNV2EAtanrld0mWMeRHqp+zJFBO4S5rRqjxsoT4caGrG4+Mlfzmc= X-Received: from seanjc798194.pdx.corp.google.com ([2620:15c:90:200:e39b:6333:b001:cb]) (user=seanjc job=sendgmr) by 2002:a25:bc0e:: with SMTP id i14mr6935877ybh.324.1633745571812; Fri, 08 Oct 2021 19:12:51 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 8 Oct 2021 19:11:57 -0700 In-Reply-To: <20211009021236.4122790-1-seanjc@google.com> Message-Id: <20211009021236.4122790-5-seanjc@google.com> Mime-Version: 1.0 References: <20211009021236.4122790-1-seanjc@google.com> X-Mailer: git-send-email 2.33.0.882.g93a45727a2-goog Subject: [PATCH v2 04/43] KVM: Force PPC to define its own rcuwait object From: Sean Christopherson To: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Paul Mackerras , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Christian Borntraeger , Janosch Frank , Paolo Bonzini Cc: James Morse , Alexandru Elisei , Suzuki K Poulose , Atish Patra , David Hildenbrand , Cornelia Huck , Claudio Imbrenda , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-mips@vger.kernel.org, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, David Matlack , Oliver Upton , Jing Zhang Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Do not define/reference kvm_vcpu.wait if __KVM_HAVE_ARCH_WQP is true, and instead force the architecture (PPC) to define its own rcuwait object. Allowing common KVM to directly access vcpu->wait without a guard makes it all too easy to introduce potential bugs, e.g. kvm_vcpu_block(), kvm_vcpu_on_spin(), and async_pf_execute() all operate on vcpu->wait, not the result of kvm_arch_vcpu_get_wait(), and so may do the wrong thing for PPC. Due to PPC's shenanigans with respect to callbacks and waits (it switches to the virtual core's wait object at KVM_RUN!?!?), it's not clear whether or not this fixes any bugs. Signed-off-by: Sean Christopherson --- arch/powerpc/include/asm/kvm_host.h | 1 + arch/powerpc/kvm/powerpc.c | 3 ++- include/linux/kvm_host.h | 2 ++ virt/kvm/async_pf.c | 2 +- virt/kvm/kvm_main.c | 9 ++++++--- 5 files changed, 12 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index 59cb38b04ede..876c10803cda 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -749,6 +749,7 @@ struct kvm_vcpu_arch { u8 irq_pending; /* Used by XIVE to signal pending guest irqs */ u32 last_inst; + struct rcuwait wait; struct rcuwait *waitp; struct kvmppc_vcore *vcore; int ret; diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 8ab90ce8738f..be22da157569 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -762,7 +762,8 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) if (err) goto out_vcpu_uninit; - vcpu->arch.waitp = &vcpu->wait; + rcuwait_init(&vcpu->arch.wait); + vcpu->arch.waitp = &vcpu->arch.wait; kvmppc_create_vcpu_debugfs(vcpu, vcpu->vcpu_id); return 0; diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 60a35d9fe259..1ced2914d9ca 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -310,7 +310,9 @@ struct kvm_vcpu { struct mutex mutex; struct kvm_run *run; +#ifndef __KVM_HAVE_ARCH_WQP struct rcuwait wait; +#endif struct pid __rcu *pid; int sigset_active; sigset_t sigset; diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c index dd777688d14a..ccb35c22785e 100644 --- a/virt/kvm/async_pf.c +++ b/virt/kvm/async_pf.c @@ -85,7 +85,7 @@ static void async_pf_execute(struct work_struct *work) trace_kvm_async_pf_completed(addr, cr2_or_gpa); - rcuwait_wake_up(&vcpu->wait); + rcuwait_wake_up(kvm_arch_vcpu_get_wait(vcpu)); mmput(mm); kvm_put_kvm(vcpu->kvm); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 7bc38549487e..5d4a90032277 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -421,7 +421,9 @@ static void kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id) vcpu->kvm = kvm; vcpu->vcpu_id = id; vcpu->pid = NULL; +#ifndef __KVM_HAVE_ARCH_WQP rcuwait_init(&vcpu->wait); +#endif kvm_async_pf_vcpu_init(vcpu); vcpu->pre_pcpu = -1; @@ -3213,6 +3215,7 @@ update_halt_poll_stats(struct kvm_vcpu *vcpu, u64 poll_ns, bool waited) */ void kvm_vcpu_block(struct kvm_vcpu *vcpu) { + struct rcuwait *wait = kvm_arch_vcpu_get_wait(vcpu); bool halt_poll_allowed = !kvm_arch_no_poll(vcpu); ktime_t start, cur, poll_end; bool waited = false; @@ -3251,7 +3254,7 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu) } - prepare_to_rcuwait(&vcpu->wait); + prepare_to_rcuwait(wait); for (;;) { set_current_state(TASK_INTERRUPTIBLE); @@ -3261,7 +3264,7 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu) waited = true; schedule(); } - finish_rcuwait(&vcpu->wait); + finish_rcuwait(wait); cur = ktime_get(); if (waited) { vcpu->stat.generic.halt_wait_ns += @@ -3460,7 +3463,7 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool yield_to_kernel_mode) continue; if (vcpu == me) continue; - if (rcuwait_active(&vcpu->wait) && + if (rcuwait_active(kvm_arch_vcpu_get_wait(vcpu)) && !vcpu_dy_runnable(vcpu)) continue; if (READ_ONCE(vcpu->preempted) && yield_to_kernel_mode &&