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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AA1D9C433EF for ; Mon, 27 Sep 2021 13:39:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 87A4061041 for ; Mon, 27 Sep 2021 13:39:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234595AbhI0Nkl (ORCPT ); Mon, 27 Sep 2021 09:40:41 -0400 Received: from mail.skyhub.de ([5.9.137.197]:55702 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234557AbhI0Nkk (ORCPT ); Mon, 27 Sep 2021 09:40:40 -0400 Received: from zn.tnic (p200300ec2f088a003e7a3db711c29d58.dip0.t-ipconnect.de [IPv6:2003:ec:2f08:8a00:3e7a:3db7:11c2:9d58]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 15AF71EC013E; Mon, 27 Sep 2021 15:38:57 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1632749937; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=VSilXSaUsjcqTdHj0wHV0zcv+Rs1cnoXDIbeePx4zfM=; b=hzSAi7KRv/M0gqs5truYx7MvEqByYxNidg7nQzGNSiJY0Yu7bvX+aMb4IImeIMFAKXG2hA 1X6s6lkqvrO6mDD0WYPYOWUg382xagbGwTjiiqc7H8wbE+2J71JGzRga7uf97IH5TlMop4 +rGksarvdVyDi2H3n9gEWAfqQ6D/uBE= Date: Mon, 27 Sep 2021 15:38:51 +0200 From: Borislav Petkov To: Paolo Bonzini Cc: Babu Moger , tglx@linutronix.de, mingo@redhat.com, x86@kernel.org, hpa@zytor.com, seanjc@google.com, vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org, tony.luck@intel.com, peterz@infradead.org, kyung.min.park@intel.com, wei.huang2@amd.com, jgross@suse.com, andrew.cooper3@citrix.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Subject: Re: [PATCH] KVM: x86: Expose Predictive Store Forwarding Disable Message-ID: References: <163244601049.30292.5855870305350227855.stgit@bmoger-ubuntu> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Mon, Sep 27, 2021 at 02:54:08PM +0200, Paolo Bonzini wrote: > There are other guests than Linux. This patch is just telling userspace > that KVM knows what the PSFD bit is. It is also possible to expose the bit > in KVM without having any #define in cpufeatures.h Ok, then there's no need for the cpufeatures.h hunk. > or without the kernel using it. For example KVM had been exposing > FSGSBASE long before Linux supported it. Ok, please do that for now then, if you want to expose it to other guests. I'm sceptical they will have a use case for it either but I'm always open to suggestions. For the same reason as for baremetal, though, I wouldn't do that and do that solely through the SSBD control but that's your call. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette