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 X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DF4CAC433ED for ; Wed, 12 May 2021 13:19:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A7FDF61363 for ; Wed, 12 May 2021 13:19:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230326AbhELNUZ (ORCPT ); Wed, 12 May 2021 09:20:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46144 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230037AbhELNUW (ORCPT ); Wed, 12 May 2021 09:20:22 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 05B9AC061574 for ; Wed, 12 May 2021 06:19:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=kM8Gv4a7if6FOAGYpIP4H4G5ELTL9yP0j2wunmulU+g=; b=IxkLR8bNVFnsDosV3gjfPgggNa 1zh6QH/LgbpHoi480Ij82xCBQAnWc5KtCeK4JpZ26xHB15CP1luAkUovYhCcfCDc4LxpINJ2rWVUJ Karqtz3BHWU6pBpxdyrBM9PJCJb3LUV4qLTYT7ozpXTk8bW8mcp1VtRf45dq4kcdcKhvInMDbfFf9 Gi6FdogMnOjwiHnQKKbWnc6FqTXjfcGcMArKgcHvfYvUQljm3UPNBhV9MmCsbnyJ7PCjbXRhm4uDG 2JxaO8B0lU0OuHL5BL45JLE65lbvnzR4pyP6i5tBEXvFeLN2TVDWFQWWUx003LIimpxYW3bJbFfsG 8Qsw3dew==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1lgolT-002sBN-Hy; Wed, 12 May 2021 13:19:04 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 22EED300242; Wed, 12 May 2021 15:18:58 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 088162870D488; Wed, 12 May 2021 15:18:58 +0200 (CEST) Date: Wed, 12 May 2021 15:18:57 +0200 From: Peter Zijlstra To: Juergen Gross Cc: Andi Kleen , Borislav Petkov , Kuppuswamy Sathyanarayanan , Andy Lutomirski , Dave Hansen , Dan Williams , Tony Luck , Kirill Shutemov , Kuppuswamy Sathyanarayanan , Raj Ashok , Sean Christopherson , linux-kernel@vger.kernel.org Subject: Re: [RFC v2 01/32] x86/paravirt: Introduce CONFIG_PARAVIRT_XL Message-ID: References: <4f8c9559dd04d8e8485c419c5ebc9471613f7928.1619458733.git.sathyanarayanan.kuppuswamy@linux.intel.com> <41463493-48bb-0e69-dcb2-3072e2ddf208@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <41463493-48bb-0e69-dcb2-3072e2ddf208@suse.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 10, 2021 at 05:56:05PM +0200, Juergen Gross wrote: > No. We have PARAVIRT_XXL for Xen PV guests, and we have PARAVIRT for > other hypervisor's guests, supporting basically the TLB flush operations > and time related operations only. Adding the halt related operations to > PARAVIRT wouldn't break anything. Also, I don't think anything modern should actually ever hit any of the HLT instructions, most everything should end up at an MWAIT. Still, do we wants to give arch_safe_halt() and halt() the PVOP_ALT_VCALL0() treatment?