From mboxrd@z Thu Jan 1 00:00:00 1970 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 EDCB7C433F5 for ; Mon, 29 Nov 2021 23:16:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232792AbhK2XTY (ORCPT ); Mon, 29 Nov 2021 18:19:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43026 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232778AbhK2XTL (ORCPT ); Mon, 29 Nov 2021 18:19:11 -0500 Received: from mail-pf1-x42b.google.com (mail-pf1-x42b.google.com [IPv6:2607:f8b0:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4AE6EC05291F for ; Mon, 29 Nov 2021 15:08:51 -0800 (PST) Received: by mail-pf1-x42b.google.com with SMTP id g19so18525294pfb.8 for ; Mon, 29 Nov 2021 15:08:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=wGXlqysNMLf5dA9ShtMuuUcB61yXXSlnUdTXbJgqyho=; b=aQ/MHWcXkD40A0P6F/6pM4uytFQ1pWDwdyAmR4hDPIKAUjO1vpeLU+g2hrC/FxndqK loB4MxuF23gDHET1FyZyFunD5Du7IPGSUpsxbh7Us1OFyB4/JhEK3lM+Ntxco0j/q7c6 QjZvaJP5Le+cmyeC/BiIoJbf4PkdiDyTTkNhIL9j8ygo81zWKZrLKTWgvABuo4P/PbSX dmlq0JFxUo7H/RqhL3jXUJtxX+CnCl9WussVvI3u8/SItZceeQnSdjRGzC5MSduA7Ky9 vjgqowrmtB3btV4elbRxg407ENgf5kCrB8pI72qo0qexp01IGdJaQWfCKYQ+vUiD+Qrc tVzg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=wGXlqysNMLf5dA9ShtMuuUcB61yXXSlnUdTXbJgqyho=; b=z7djDA30sPVPXDy84nR2CfeiyZM27XT2dJrxdfed/qeed6NVGs3o3eLnv8OydElplG buZBsUODBzd5INHITmP+bVs/lF1UGQM/JRTUYPJT5XWq0NeFfo061Yv6PTOprGy59CI2 7rQKT9e9CTvhjidyrGZo7JA/bd12NZbWmhDRBaEvZCDVKNxLiY5G5tf1faiblxCB9xBc /+HL2vq6SIxChHtz+KCx9Je+iTgVoYI0J8R1llhD+MHLG7QococrYzCezFTgCCiPQjfB SOnl5MxKdLBRIQHnO+YUEkQszkZ3iHCcqpJBjfkY51K4gKsks/gnoH/3VieO/6wihSxk YkfQ== X-Gm-Message-State: AOAM533LjjW8svHoCHIxMphlXmmyp42WaeM55K/ycKiORKf8hfavTYbc Hcx1NTKn9CNKI1WT4ISKZKMSKg== X-Google-Smtp-Source: ABdhPJxK2jL73IyU2JgUo1UmNPcjuYlETOcdXVWiZubhTKgRJr0mbwX0U3dEq0NUGzE3QbDNfd6SHg== X-Received: by 2002:a63:f91f:: with SMTP id h31mr24053499pgi.538.1638227330585; Mon, 29 Nov 2021 15:08:50 -0800 (PST) Received: from google.com (157.214.185.35.bc.googleusercontent.com. [35.185.214.157]) by smtp.gmail.com with ESMTPSA id y190sm18403540pfg.153.2021.11.29.15.08.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 29 Nov 2021 15:08:50 -0800 (PST) Date: Mon, 29 Nov 2021 23:08:46 +0000 From: Sean Christopherson To: Paolo Bonzini Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, pgonda@google.com Subject: Re: [PATCH 09/12] KVM: SEV: Do COPY_ENC_CONTEXT_FROM with both VMs locked Message-ID: References: <20211123005036.2954379-1-pbonzini@redhat.com> <20211123005036.2954379-10-pbonzini@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211123005036.2954379-10-pbonzini@redhat.com> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Mon, Nov 22, 2021, Paolo Bonzini wrote: > Now that we have a facility to lock two VMs with deadlock > protection, use it for the creation of mirror VMs as well. One of > COPY_ENC_CONTEXT_FROM(dst, src) and COPY_ENC_CONTEXT_FROM(src, dst) > would always fail, so the combination is nonsensical and it is okay to > return -EBUSY if it is attempted. > > This sidesteps the question of what happens if a VM is > MOVE_ENC_CONTEXT_FROM'd at the same time as it is > COPY_ENC_CONTEXT_FROM'd: the locking prevents that from > happening. > > Cc: Peter Gonda > Cc: Sean Christopherson > Signed-off-by: Paolo Bonzini > --- > arch/x86/kvm/svm/sev.c | 69 +++++++++++++++++------------------------- > 1 file changed, 27 insertions(+), 42 deletions(-) > > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c > index c1eb1c83401d..025d9731b66c 100644 > --- a/arch/x86/kvm/svm/sev.c > +++ b/arch/x86/kvm/svm/sev.c > @@ -1548,6 +1548,9 @@ static int sev_lock_two_vms(struct kvm *dst_kvm, struct kvm *src_kvm) > struct kvm_sev_info *dst_sev = &to_kvm_svm(dst_kvm)->sev_info; > struct kvm_sev_info *src_sev = &to_kvm_svm(src_kvm)->sev_info; > > + if (dst_kvm == src_kvm) > + return -EINVAL; This should go into KVM: SEV: cleanup locking for KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM because before that, KVM would never attempt mutex_lock() on the second VM, one of the SEV || !SEV was guaranteed to fail. With that change, Reviewed-by: Sean Christopherson