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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DEA5CC3ABCC for ; Tue, 13 May 2025 13:42:00 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.982851.1369199 (Exim 4.92) (envelope-from ) id 1uEptG-0002yV-Fv; Tue, 13 May 2025 13:41:50 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 982851.1369199; Tue, 13 May 2025 13:41:50 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1uEptG-0002yO-CS; Tue, 13 May 2025 13:41:50 +0000 Received: by outflank-mailman (input) for mailman id 982851; Tue, 13 May 2025 13:41:49 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1uEptF-0002yG-RS for xen-devel@lists.xenproject.org; Tue, 13 May 2025 13:41:49 +0000 Received: from mail-pf1-x432.google.com (mail-pf1-x432.google.com [2607:f8b0:4864:20::432]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id 01fcc3b2-3000-11f0-9ffb-bf95429c2676; Tue, 13 May 2025 15:41:44 +0200 (CEST) Received: by mail-pf1-x432.google.com with SMTP id d2e1a72fcca58-7424ccbef4eso3005006b3a.2 for ; Tue, 13 May 2025 06:41:44 -0700 (PDT) Received: from localhost ([84.78.159.3]) by smtp.gmail.com with UTF8SMTPSA id d2e1a72fcca58-74237a8efa2sm7741177b3a.165.2025.05.13.06.41.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 13 May 2025 06:41:42 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 01fcc3b2-3000-11f0-9ffb-bf95429c2676 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=citrix.com; s=google; t=1747143703; x=1747748503; darn=lists.xenproject.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=CjBhEUReEcpnOvmXghRfokYvtQrmimmin9Z5BxHCOeM=; b=dJE/qxP5ubbiJ7LEWxRl1Y7641rPhErWy/reZBx7SvxSPmgkBgFcRepB4FiFssquh9 Uj+8Ui+WslXG8GUXRNnI6VD+8u29u2ow2B8dyXO6xVHZ8IwvG7TQhPDxucc3FXOOTzF7 50t8TjieVU7Fl2iOcv4KHzqik8HQezfwoEk7g= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1747143703; x=1747748503; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=CjBhEUReEcpnOvmXghRfokYvtQrmimmin9Z5BxHCOeM=; b=gailnw3stJhKDjUZVt5edzafJtylwHhVSaAZQtWpwGdCCC6sZON1Tb4XrnFKeG3TmD hdfHAlTaf/TGDQkySuuQR60lBQSlwJ9UZp9Uh3gP/k9RBPfUaWQ/ZAV1b9J3lYLrApCi CnQluJna57PaQgv4zXl4OQksvM7fpJvoKnmZPfurmOtihLdSzah4MrjdSGkmoeJWd5yn 89aj5g+llEi6j5vkRXmON/a76FttGVPxCGEgJiHfygKOg80BeOpHA+4QsDdPp/RHlcPJ aFeST/0pSFjPG/2a1dA4bInHdmhQsNOEb7Z8pvtPfO8yOMnvwww8hti4sHAdSrD+bw5k EWZw== X-Gm-Message-State: AOJu0Yw2QUuLfaM5uCgsGAPH0GMurX0kjuT35m9vAQ3IB/MleFdCxjb6 LzUhcsRof5hj7JEIeDDPOoVqGKFVBUKobzpk4Nz2+EW/sBGz7gxNE7gYJeRG8ik= X-Gm-Gg: ASbGncvZkAbiWYB+K1YrjW2Gi2LWSu6efWqGiievZK5iO8iGaftNBapOaHVNPN9pSdp NbVEONQ2npOga+g9tB4nvrUtyLzcN62U4pQSP/UVnHHBSSCxB1BwRlzYc1JK8V3g5HSuHvNpUHZ Iw4UxeCe40VVEoWTIOLPqFWgmfXzf9kAjK+gboq4jmNmRUQ0dY/XhZ8EIA4Ao07V/nZo1n6Ys36 0cccpy1lNM5bfFfsesPIgaYAeKAKN8oB5aYl1ZCT3f9fm2YMkGzVZGXr386Jefu/YmeEUxveFaA Frcmch/IAvLzihN5wV8aPfNxH16b20eTStyHMn13ml7rX8XM4/JgJYvfa5ElhQ== X-Google-Smtp-Source: AGHT+IHPsTEwJwTw0bg9EfuNWCe6ZpabY7d2+vlVP1CkkKj5uvLszkhAwWTBnVnfbz24xZwVjBJfCg== X-Received: by 2002:a05:6a00:4b53:b0:740:9c06:1cff with SMTP id d2e1a72fcca58-7423c0163dfmr24716454b3a.23.1747143703267; Tue, 13 May 2025 06:41:43 -0700 (PDT) Date: Tue, 13 May 2025 15:41:37 +0200 From: Roger Pau =?utf-8?B?TW9ubsOp?= To: Jan Beulich Cc: "xen-devel@lists.xenproject.org" , Andrew Cooper , Wei Liu , Kevin Tian , Jun Nakajima Subject: Re: [PATCH v2 2/6] x86/HVM: restrict guest-induced WBINVD to cache writeback Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: On Wed, May 03, 2023 at 11:45:22AM +0200, Jan Beulich wrote: > We allow its use for writeback purposes only anyway, so let's also carry > these out that way on capable hardware. "for writeback purposes only" > is such the case because we cannot guarantee the guest in which state the cache will be when resuming from a wbinvd operation, and hence won't be "clean"? It's my understanding that the same is possible on native, as the CPU might speculatively pull lines into the cache. So there's no reason for an OS to use wbinvd if wbnoinvd is available? Thanks, Roger.