From patchwork Mon Aug 7 23:01:09 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ackerley Tng X-Patchwork-Id: 13345269 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 2BD36C001DE for ; Mon, 7 Aug 2023 23:02:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231205AbjHGXCH (ORCPT ); Mon, 7 Aug 2023 19:02:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40696 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230486AbjHGXBx (ORCPT ); Mon, 7 Aug 2023 19:01:53 -0400 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4D3281724 for ; Mon, 7 Aug 2023 16:01:41 -0700 (PDT) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-5868992ddd4so58814227b3.0 for ; Mon, 07 Aug 2023 16:01:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1691449300; x=1692054100; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=q+4P4F8zMt4Dd2qn/DvvFJFWH4ILq58+E3D5i6R7pxU=; b=Q0k0MahZIE5dc0IRAXJwKTTZDSg3cZi9yWSlFQHuosf4l1pwmxjRYMo/MoeQmihaZF /Y2YJV0eCS16QuqY2J5LouzDTRRKPh36yzofSbiHq1fXkCRSrQHQ60fAySXo3XtnWoEE gCtigQEluVr3pUX7NMZgK3pdcWTNlmRFpkspeMWfxJty8wvX3j7UJaM07bfYOvR23gEO qadalUmfqPjBKRKKKfUdB/qrNcPo7nYwsM3FclpqeHCX7Li+9n1WiMkWpTTGRnw9J5sl sd+kNZfSjZyU2B3lWLOyXRhsh30tsMnrORLG9tJPdD0PiRGac+EO0SELHeX9PQUK8o7z Lm3w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1691449300; x=1692054100; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=q+4P4F8zMt4Dd2qn/DvvFJFWH4ILq58+E3D5i6R7pxU=; b=HQDIG5W113H4JHNKkhcMkseEPCo3oyIPXv+lH9JEIYK7NgeqdFxRzwkCcUHzcpUJdw Jo+ApYbcsdYnNjTr0CDcnyXZQriNIL3zT5ELZIv6ChI4ucPZjq9MHOMXYVG/DFcQn37o X2UprXOd+Zt9z0Y3o0UMBq1mZW562cSZPvXiDCusq6HpuVrmT+vIf7sTH3uSVHOrXF9c TEwW9NWm4a7FSzg1wFQnQkmdPQofb2zF7qr8EbCmHiM9o/9v5NEJ4NxYxRcvvSogUp5L F1fausrTd0MXAFZcwUS1T+9p0dgkyBUloWYnprPAQ+dUmLtGeCNqcECKAlJcMPBKRBno qjcA== X-Gm-Message-State: AOJu0YzHVQPk6YicegZkni3qDEtThPbjvu5hcdKK8hjql+h1MBPjVFaH qrgcZkbo93Frg37kp+uRxp6LzP/4pBOuUDfe1w== X-Google-Smtp-Source: AGHT+IHC/bXPExjJXROsLpCwLAALYI0hnMQCZ2IOPhDw3Q9QpEGX9jq+kjJcUdk7vT3m1m3a/pU0JCUarVvYuN8xkw== X-Received: from ackerleytng-ctop.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:13f8]) (user=ackerleytng job=sendgmr) by 2002:a81:ac07:0:b0:583:5471:1717 with SMTP id k7-20020a81ac07000000b0058354711717mr89606ywh.10.1691449300448; Mon, 07 Aug 2023 16:01:40 -0700 (PDT) Date: Mon, 7 Aug 2023 23:01:09 +0000 In-Reply-To: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.41.0.640.ga95def55d0-goog Message-ID: Subject: [RFC PATCH 06/11] KVM: x86: Refactor common code out of sev.c From: Ackerley Tng To: pbonzini@redhat.com, seanjc@google.com, tglx@linutronix.de, x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, shuah@kernel.org, andrew.jones@linux.dev, ricarkol@google.com, chao.p.peng@linux.intel.com, tabba@google.com, jarkko@kernel.org, yu.c.zhang@linux.intel.com, vannapurve@google.com, ackerleytng@google.com, erdemaktas@google.com, mail@maciej.szmigiero.name, vbabka@suse.cz, david@redhat.com, qperret@google.com, michael.roth@amd.com, wei.w.wang@intel.com, liam.merwick@oracle.com, isaku.yamahata@gmail.com, kirill.shutemov@linux.intel.com, Sagi Shahar Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Split sev_lock_two_vms() into kvm_mark_migration_in_progress() and kvm_lock_two_vms() and refactor sev.c to use these two new functions. Co-developed-by: Sagi Shahar Signed-off-by: Sagi Shahar Co-developed-by: Vishal Annapurve Signed-off-by: Vishal Annapurve Signed-off-by: Ackerley Tng --- arch/x86/kvm/svm/sev.c | 59 ++++++++++------------------------------ arch/x86/kvm/x86.c | 62 ++++++++++++++++++++++++++++++++++++++++++ arch/x86/kvm/x86.h | 6 ++++ 3 files changed, 82 insertions(+), 45 deletions(-) diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 725289b523c7..3c4313417966 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -1554,47 +1554,6 @@ static bool is_cmd_allowed_from_mirror(u32 cmd_id) return false; } -static int sev_lock_two_vms(struct kvm *dst_kvm, struct kvm *src_kvm) -{ - int r = -EBUSY; - - if (dst_kvm == src_kvm) - return -EINVAL; - - /* - * Bail if these VMs are already involved in a migration to avoid - * deadlock between two VMs trying to migrate to/from each other. - */ - if (atomic_cmpxchg_acquire(&dst_kvm->migration_in_progress, 0, 1)) - return -EBUSY; - - if (atomic_cmpxchg_acquire(&src_kvm->migration_in_progress, 0, 1)) - goto release_dst; - - r = -EINTR; - if (mutex_lock_killable(&dst_kvm->lock)) - goto release_src; - if (mutex_lock_killable_nested(&src_kvm->lock, SINGLE_DEPTH_NESTING)) - goto unlock_dst; - return 0; - -unlock_dst: - mutex_unlock(&dst_kvm->lock); -release_src: - atomic_set_release(&src_kvm->migration_in_progress, 0); -release_dst: - atomic_set_release(&dst_kvm->migration_in_progress, 0); - return r; -} - -static void sev_unlock_two_vms(struct kvm *dst_kvm, struct kvm *src_kvm) -{ - mutex_unlock(&dst_kvm->lock); - mutex_unlock(&src_kvm->lock); - atomic_set_release(&dst_kvm->migration_in_progress, 0); - atomic_set_release(&src_kvm->migration_in_progress, 0); -} - /* vCPU mutex subclasses. */ enum sev_migration_role { SEV_MIGRATION_SOURCE = 0, @@ -1777,9 +1736,12 @@ int sev_vm_move_enc_context_from(struct kvm *kvm, unsigned int source_fd) } source_kvm = f.file->private_data; - ret = sev_lock_two_vms(kvm, source_kvm); + ret = kvm_mark_migration_in_progress(kvm, source_kvm); if (ret) goto out_fput; + ret = kvm_lock_two_vms(kvm, source_kvm); + if (ret) + goto out_mark_migration_done; if (sev_guest(kvm) || !sev_guest(source_kvm)) { ret = -EINVAL; @@ -1823,8 +1785,10 @@ int sev_vm_move_enc_context_from(struct kvm *kvm, unsigned int source_fd) sev_misc_cg_uncharge(cg_cleanup_sev); put_misc_cg(cg_cleanup_sev->misc_cg); cg_cleanup_sev->misc_cg = NULL; +out_mark_migration_done: + kvm_mark_migration_done(kvm, source_kvm); out_unlock: - sev_unlock_two_vms(kvm, source_kvm); + kvm_unlock_two_vms(kvm, source_kvm); out_fput: fdput(f); return ret; @@ -2057,9 +2021,12 @@ int sev_vm_copy_enc_context_from(struct kvm *kvm, unsigned int source_fd) } source_kvm = f.file->private_data; - ret = sev_lock_two_vms(kvm, source_kvm); + ret = kvm_mark_migration_in_progress(kvm, source_kvm); if (ret) goto e_source_fput; + ret = kvm_lock_two_vms(kvm, source_kvm); + if (ret) + goto e_mark_migration_done; /* * Mirrors of mirrors should work, but let's not get silly. Also @@ -2100,7 +2067,9 @@ int sev_vm_copy_enc_context_from(struct kvm *kvm, unsigned int source_fd) */ e_unlock: - sev_unlock_two_vms(kvm, source_kvm); + kvm_unlock_two_vms(kvm, source_kvm); +e_mark_migration_done: + kvm_mark_migration_done(kvm, source_kvm); e_source_fput: fdput(f); return ret; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index de195ad83ec0..494b75ef7197 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4340,6 +4340,68 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) } EXPORT_SYMBOL_GPL(kvm_get_msr_common); +int kvm_mark_migration_in_progress(struct kvm *dst_kvm, struct kvm *src_kvm) +{ + int r; + + if (dst_kvm == src_kvm) + return -EINVAL; + + /* + * Bail if these VMs are already involved in a migration to avoid + * deadlock between two VMs trying to migrate to/from each other. + */ + r = -EBUSY; + if (atomic_cmpxchg_acquire(&dst_kvm->migration_in_progress, 0, 1)) + return r; + + if (atomic_cmpxchg_acquire(&src_kvm->migration_in_progress, 0, 1)) + goto release_dst; + + return 0; + +release_dst: + atomic_set_release(&dst_kvm->migration_in_progress, 0); + return r; +} +EXPORT_SYMBOL_GPL(kvm_mark_migration_in_progress); + +void kvm_mark_migration_done(struct kvm *dst_kvm, struct kvm *src_kvm) +{ + atomic_set_release(&dst_kvm->migration_in_progress, 0); + atomic_set_release(&src_kvm->migration_in_progress, 0); +} +EXPORT_SYMBOL_GPL(kvm_mark_migration_done); + +int kvm_lock_two_vms(struct kvm *dst_kvm, struct kvm *src_kvm) +{ + int r; + + if (dst_kvm == src_kvm) + return -EINVAL; + + r = -EINTR; + if (mutex_lock_killable(&dst_kvm->lock)) + return r; + + if (mutex_lock_killable_nested(&src_kvm->lock, SINGLE_DEPTH_NESTING)) + goto unlock_dst; + + return 0; + +unlock_dst: + mutex_unlock(&dst_kvm->lock); + return r; +} +EXPORT_SYMBOL_GPL(kvm_lock_two_vms); + +void kvm_unlock_two_vms(struct kvm *dst_kvm, struct kvm *src_kvm) +{ + mutex_unlock(&dst_kvm->lock); + mutex_unlock(&src_kvm->lock); +} +EXPORT_SYMBOL_GPL(kvm_unlock_two_vms); + /* * Read or write a bunch of msrs. All parameters are kernel addresses. * diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h index 82e3dafc5453..4c6edaf5ac5b 100644 --- a/arch/x86/kvm/x86.h +++ b/arch/x86/kvm/x86.h @@ -539,4 +539,10 @@ int kvm_sev_es_string_io(struct kvm_vcpu *vcpu, unsigned int size, unsigned int port, void *data, unsigned int count, int in); +int kvm_mark_migration_in_progress(struct kvm *dst_kvm, struct kvm *src_kvm); +void kvm_mark_migration_done(struct kvm *dst_kvm, struct kvm *src_kvm); + +int kvm_lock_two_vms(struct kvm *dst_kvm, struct kvm *src_kvm); +void kvm_unlock_two_vms(struct kvm *dst_kvm, struct kvm *src_kvm); + #endif