From patchwork Thu Feb 27 23:06:30 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Keith Busch X-Patchwork-Id: 13995340 Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A315F27128D for ; Thu, 27 Feb 2025 23:06:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=67.231.145.42 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740697608; cv=none; b=ugNvl1eCjJu0YaoGI19bmP1gv8xHZ+pE2cwZ6EINCuK0vv+mI6RScnW4Dl2LI7l/P59ii6mswPT7iS48xaJBTd2K0nl35xL4sZIMYqcql/k8xRZxaO0pXC+oQ832ROYGHZmRViBqo0N94idXX3hf3OKviBz45fjaL+wMKfUxvT0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740697608; c=relaxed/simple; bh=n20JTjqARi3bIKMGVpnP5071GH6mRPRCGiKcCnHkOuw=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=upyZ1LJsHTfx3xg9GzrD6WXK2aEF3eCUL1H1+T26Zt2BaShFTT8EwRw9KVfONjOavu0odL0/NXmt/xB/9K+kuSViLJj0+AqJ9D02gNRbDPekceS5PMolPBDv9pGNPQZCdT9xSBKL6R9s2nfeK5aKFzdlSymGbAqcyfqDt7eCihc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=meta.com; spf=pass smtp.mailfrom=meta.com; dkim=pass (2048-bit key) header.d=meta.com header.i=@meta.com header.b=jGfJyFnA; arc=none smtp.client-ip=67.231.145.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=meta.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=meta.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=meta.com header.i=@meta.com header.b="jGfJyFnA" Received: from pps.filterd (m0148461.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 51RMbm1e032471 for ; Thu, 27 Feb 2025 15:06:45 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=meta.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=s2048-2021-q4; bh=vCIsZt403ulsh6i+1Y7fMucf02/XpxKVHcBj4IVeiiA=; b=jGfJyFnAQszI 2ufui3RvKjM83ALgN63+lwWFbsbDB4L2MAQgcbedrS8irYOU9R6KNTZoAHosD9pj odb2mhidwdrdbHsMvoqSA4Ssw4597YjDBRGD0QdoFElP4ndpHVhGTHc+6gwTKew+ FzvXUlbYbEK1B2MwWxbly1zZupamgNeQD9c5eA27ms2asLLXClVf+j/V3spHPMcG uxJH3fBpDOkAZASBzkKjYoB+mVefeYTOznEzDl2/T8atnNnkFu0qVQxYAhVFU/vO DP1T3BwBG8/k65iaKppmztGjEp0V0ZKE1yc+Cn0qw8pfEfRlU4xzAhzUD8xSBVGD zBXNJHaEYw== Received: from maileast.thefacebook.com ([163.114.135.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 4530qwga3s-13 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Thu, 27 Feb 2025 15:06:45 -0800 (PST) Received: from twshared18153.09.ash9.facebook.com (2620:10d:c0a8:fe::f072) by mail.thefacebook.com (2620:10d:c0a9:6f::237c) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.2.1544.14; Thu, 27 Feb 2025 23:06:34 +0000 Received: by devbig638.nha1.facebook.com (Postfix, from userid 544533) id 9A9C318885339; Thu, 27 Feb 2025 15:06:31 -0800 (PST) From: Keith Busch To: , , CC: , , , , Keith Busch Subject: [PATCHv3 1/2] vhost: return task creation error instead of NULL Date: Thu, 27 Feb 2025 15:06:30 -0800 Message-ID: <20250227230631.303431-2-kbusch@meta.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20250227230631.303431-1-kbusch@meta.com> References: <20250227230631.303431-1-kbusch@meta.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: C-6vNMll4xCMybdJAZz9RlkhkAOgBTL5 X-Proofpoint-GUID: C-6vNMll4xCMybdJAZz9RlkhkAOgBTL5 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1057,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-02-27_08,2025-02-27_01,2024-11-22_01 From: Keith Busch Lets callers distinguish why the vhost task creation failed. No one currently cares why it failed, so no real runtime change from this patch, but that will not be the case for long. Signed-off-by: Keith Busch Reviewed-by: Mike Christie --- arch/x86/kvm/mmu/mmu.c | 2 +- drivers/vhost/vhost.c | 2 +- kernel/vhost_task.c | 4 ++-- 3 files changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index d4ac4a1f8b81b..18ca1ea6dc240 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -7471,7 +7471,7 @@ static void kvm_mmu_start_lpage_recovery(struct once *once) kvm_nx_huge_page_recovery_worker_kill, kvm, "kvm-nx-lpage-recovery"); - if (!nx_thread) + if (IS_ERR(nx_thread)) return; vhost_task_start(nx_thread); diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 9ac25d08f473e..63612faeab727 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -666,7 +666,7 @@ static struct vhost_worker *vhost_worker_create(struct vhost_dev *dev) vtsk = vhost_task_create(vhost_run_work_list, vhost_worker_killed, worker, name); - if (!vtsk) + if (IS_ERR(vtsk)) goto free_worker; mutex_init(&worker->mutex); diff --git a/kernel/vhost_task.c b/kernel/vhost_task.c index 8800f5acc0071..2ef2e1b800916 100644 --- a/kernel/vhost_task.c +++ b/kernel/vhost_task.c @@ -133,7 +133,7 @@ struct vhost_task *vhost_task_create(bool (*fn)(void *), vtsk = kzalloc(sizeof(*vtsk), GFP_KERNEL); if (!vtsk) - return NULL; + return ERR_PTR(-ENOMEM); init_completion(&vtsk->exited); mutex_init(&vtsk->exit_mutex); vtsk->data = arg; @@ -145,7 +145,7 @@ struct vhost_task *vhost_task_create(bool (*fn)(void *), tsk = copy_process(NULL, 0, NUMA_NO_NODE, &args); if (IS_ERR(tsk)) { kfree(vtsk); - return NULL; + return ERR_PTR(PTR_ERR(tsk)); } vtsk->task = tsk; From patchwork Thu Feb 27 23:06:31 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Keith Busch X-Patchwork-Id: 13995339 Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 35C2523E356 for ; Thu, 27 Feb 2025 23:06:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=67.231.145.42 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; 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Thu, 27 Feb 2025 15:06:40 -0800 (PST) Received: from twshared40462.17.frc2.facebook.com (2620:10d:c0a8:1c::11) by mail.thefacebook.com (2620:10d:c0a9:6f::237c) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.2.1544.14; Thu, 27 Feb 2025 23:06:28 +0000 Received: by devbig638.nha1.facebook.com (Postfix, from userid 544533) id A2B4D1888533A; Thu, 27 Feb 2025 15:06:31 -0800 (PST) From: Keith Busch To: , , CC: , , , , Keith Busch Subject: [PATCHv3 2/2] kvm: retry nx_huge_page_recovery_thread creation Date: Thu, 27 Feb 2025 15:06:31 -0800 Message-ID: <20250227230631.303431-3-kbusch@meta.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20250227230631.303431-1-kbusch@meta.com> References: <20250227230631.303431-1-kbusch@meta.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: lf518XvDOzkUaWOBiIctAhsnLoy1UR1A X-Proofpoint-GUID: lf518XvDOzkUaWOBiIctAhsnLoy1UR1A X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1057,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-02-27_08,2025-02-27_01,2024-11-22_01 From: Sean Christopherson A VMM may send a signal to its threads while they've entered KVM_RUN. If that thread happens to be trying to make the huge page recovery vhost task, then it fails with -ERESTARTNOINTR. We need to retry if that happens, so call_once needs to be retryable. Make call_once complete only if what it called was successful. [implemented the kvm user side] Signed-off-by: Keith Busch --- arch/x86/kvm/mmu/mmu.c | 10 ++++------ include/linux/call_once.h | 16 +++++++++++----- 2 files changed, 15 insertions(+), 11 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 18ca1ea6dc240..8160870398b90 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -7460,7 +7460,7 @@ static bool kvm_nx_huge_page_recovery_worker(void *data) return true; } -static void kvm_mmu_start_lpage_recovery(struct once *once) +static int kvm_mmu_start_lpage_recovery(struct once *once) { struct kvm_arch *ka = container_of(once, struct kvm_arch, nx_once); struct kvm *kvm = container_of(ka, struct kvm, arch); @@ -7472,12 +7472,13 @@ static void kvm_mmu_start_lpage_recovery(struct once *once) kvm, "kvm-nx-lpage-recovery"); if (IS_ERR(nx_thread)) - return; + return PTR_ERR(nx_thread); vhost_task_start(nx_thread); /* Make the task visible only once it is fully started. */ WRITE_ONCE(kvm->arch.nx_huge_page_recovery_thread, nx_thread); + return 0; } int kvm_mmu_post_init_vm(struct kvm *kvm) @@ -7485,10 +7486,7 @@ int kvm_mmu_post_init_vm(struct kvm *kvm) if (nx_hugepage_mitigation_hard_disabled) return 0; - call_once(&kvm->arch.nx_once, kvm_mmu_start_lpage_recovery); - if (!kvm->arch.nx_huge_page_recovery_thread) - return -ENOMEM; - return 0; + return call_once(&kvm->arch.nx_once, kvm_mmu_start_lpage_recovery); } void kvm_mmu_pre_destroy_vm(struct kvm *kvm) diff --git a/include/linux/call_once.h b/include/linux/call_once.h index 6261aa0b3fb00..ddcfd91493eaa 100644 --- a/include/linux/call_once.h +++ b/include/linux/call_once.h @@ -26,20 +26,26 @@ do { \ __once_init((once), #once, &__key); \ } while (0) -static inline void call_once(struct once *once, void (*cb)(struct once *)) +static inline int call_once(struct once *once, int (*cb)(struct once *)) { + int r; + /* Pairs with atomic_set_release() below. */ if (atomic_read_acquire(&once->state) == ONCE_COMPLETED) - return; + return 0; guard(mutex)(&once->lock); WARN_ON(atomic_read(&once->state) == ONCE_RUNNING); if (atomic_read(&once->state) != ONCE_NOT_STARTED) - return; + return -EINVAL; atomic_set(&once->state, ONCE_RUNNING); - cb(once); - atomic_set_release(&once->state, ONCE_COMPLETED); + r = cb(once); + if (r) + atomic_set(&once->state, ONCE_NOT_STARTED); + else + atomic_set_release(&once->state, ONCE_COMPLETED); + return r; } #endif /* _LINUX_CALL_ONCE_H */