From patchwork Mon Oct 4 12:51:47 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 12533883 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 E293DC433EF for ; Mon, 4 Oct 2021 13:32:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CCF18611C1 for ; Mon, 4 Oct 2021 13:32:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237443AbhJDNdy (ORCPT ); Mon, 4 Oct 2021 09:33:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:47478 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237185AbhJDNbu (ORCPT ); Mon, 4 Oct 2021 09:31:50 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6CB2F61BA2; Mon, 4 Oct 2021 13:14:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1633353261; bh=fgpLNK0QJX5G7bMV1QQIBI+1zCB4DxuGWwDN6fjnozQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mUXqn+ZlYge3ioQAKKhiUpZof36dvazghLsJXbVaN0r3cG6PxPRrhedUdvVvZNEnw 1NvVTn5R+bOEUQtjiWFBLhXhEt/QVtYhOSrbQD7hT1RWMjiwLbGQg2cPO/TzqjNxPU eQhZm+mLitUaFcDPZXIFMktrlFvANMOCyfselwPk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Peter Gonda , Marc Orr , Paolo Bonzini , Sean Christopherson , Brijesh Singh , kvm@vger.kernel.org Subject: [PATCH 5.14 057/172] KVM: SEV: Acquire vcpu mutex when updating VMSA Date: Mon, 4 Oct 2021 14:51:47 +0200 Message-Id: <20211004125046.837857428@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211004125044.945314266@linuxfoundation.org> References: <20211004125044.945314266@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Peter Gonda commit bb18a677746543e7f5eeb478129c92cedb0f9658 upstream. The update-VMSA ioctl touches data stored in struct kvm_vcpu, and therefore should not be performed concurrently with any VCPU ioctl that might cause KVM or the processor to use the same data. Adds vcpu mutex guard to the VMSA updating code. Refactors out __sev_launch_update_vmsa() function to deal with per vCPU parts of sev_launch_update_vmsa(). Fixes: ad73109ae7ec ("KVM: SVM: Provide support to launch and run an SEV-ES guest") Signed-off-by: Peter Gonda Cc: Marc Orr Cc: Paolo Bonzini Cc: Sean Christopherson Cc: Brijesh Singh Cc: kvm@vger.kernel.org Cc: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org Message-Id: <20210915171755.3773766-1-pgonda@google.com> Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/svm/sev.c | 53 +++++++++++++++++++++++++++---------------------- 1 file changed, 30 insertions(+), 23 deletions(-) --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -596,43 +596,50 @@ static int sev_es_sync_vmsa(struct vcpu_ return 0; } -static int sev_launch_update_vmsa(struct kvm *kvm, struct kvm_sev_cmd *argp) +static int __sev_launch_update_vmsa(struct kvm *kvm, struct kvm_vcpu *vcpu, + int *error) { - struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; struct sev_data_launch_update_vmsa vmsa; + struct vcpu_svm *svm = to_svm(vcpu); + int ret; + + /* Perform some pre-encryption checks against the VMSA */ + ret = sev_es_sync_vmsa(svm); + if (ret) + return ret; + + /* + * The LAUNCH_UPDATE_VMSA command will perform in-place encryption of + * the VMSA memory content (i.e it will write the same memory region + * with the guest's key), so invalidate it first. + */ + clflush_cache_range(svm->vmsa, PAGE_SIZE); + + vmsa.reserved = 0; + vmsa.handle = to_kvm_svm(kvm)->sev_info.handle; + vmsa.address = __sme_pa(svm->vmsa); + vmsa.len = PAGE_SIZE; + return sev_issue_cmd(kvm, SEV_CMD_LAUNCH_UPDATE_VMSA, &vmsa, error); +} + +static int sev_launch_update_vmsa(struct kvm *kvm, struct kvm_sev_cmd *argp) +{ struct kvm_vcpu *vcpu; int i, ret; if (!sev_es_guest(kvm)) return -ENOTTY; - vmsa.reserved = 0; - kvm_for_each_vcpu(i, vcpu, kvm) { - struct vcpu_svm *svm = to_svm(vcpu); - - /* Perform some pre-encryption checks against the VMSA */ - ret = sev_es_sync_vmsa(svm); + ret = mutex_lock_killable(&vcpu->mutex); if (ret) return ret; - /* - * The LAUNCH_UPDATE_VMSA command will perform in-place - * encryption of the VMSA memory content (i.e it will write - * the same memory region with the guest's key), so invalidate - * it first. - */ - clflush_cache_range(svm->vmsa, PAGE_SIZE); - - vmsa.handle = sev->handle; - vmsa.address = __sme_pa(svm->vmsa); - vmsa.len = PAGE_SIZE; - ret = sev_issue_cmd(kvm, SEV_CMD_LAUNCH_UPDATE_VMSA, &vmsa, - &argp->error); + ret = __sev_launch_update_vmsa(kvm, vcpu, &argp->error); + + mutex_unlock(&vcpu->mutex); if (ret) return ret; - - svm->vcpu.arch.guest_state_protected = true; } return 0;