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 375E4C433FE for ; Mon, 28 Feb 2022 10:48:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234929AbiB1Ktb (ORCPT ); Mon, 28 Feb 2022 05:49:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43328 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234907AbiB1KtY (ORCPT ); Mon, 28 Feb 2022 05:49:24 -0500 Received: from smtp-fw-6001.amazon.com (smtp-fw-6001.amazon.com [52.95.48.154]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 52B894DF7B; Mon, 28 Feb 2022 02:48:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.de; i=@amazon.de; q=dns/txt; s=amazon201209; t=1646045327; x=1677581327; h=date:from:to:cc:message-id:references:mime-version: in-reply-to:subject; bh=wtlDx4jEE4jGyIxehaIcjYydOOp8V9gGqhKFY2pAxek=; b=lmL4Ao9d38OqN10++Ib0UXf3kdMmNoqbjsuluw2oVu3tHXIvYLaUfibB IN4HN4RzlUON9BAsTufdAkmAydE4rjHJ/7D3bXWQ9qqqWsJLD3XhNq/uo v9EweWB5T07szzF4GFFgGyveMxUMRbdb0SklTouSGDor41wh9xdsBB09X U=; X-IronPort-AV: E=Sophos;i="5.90,142,1643673600"; d="scan'208";a="181712404" Subject: Re: [PATCH 4/4] KVM: x86: hyper-v: HVCALL_SEND_IPI_EX is an XMM fast hypercall Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-iad-1box-d-74e80b3c.us-east-1.amazon.com) ([10.43.8.6]) by smtp-border-fw-6001.iad6.amazon.com with ESMTP; 28 Feb 2022 10:48:36 +0000 Received: from EX13D28EUC003.ant.amazon.com (iad12-ws-svc-p26-lb9-vlan3.iad.amazon.com [10.40.163.38]) by email-inbound-relay-iad-1box-d-74e80b3c.us-east-1.amazon.com (Postfix) with ESMTPS id 0220F829DD; Mon, 28 Feb 2022 10:48:34 +0000 (UTC) Received: from 147dda3edfb6.ant.amazon.com (10.43.160.103) by EX13D28EUC003.ant.amazon.com (10.43.164.43) with Microsoft SMTP Server (TLS) id 15.0.1497.28; Mon, 28 Feb 2022 10:48:30 +0000 Date: Mon, 28 Feb 2022 11:48:26 +0100 From: Siddharth Chandrasekaran To: Vitaly Kuznetsov CC: , Paolo Bonzini , Sean Christopherson , Wanpeng Li , Jim Mattson , Message-ID: References: <20220222154642.684285-1-vkuznets@redhat.com> <20220222154642.684285-5-vkuznets@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20220222154642.684285-5-vkuznets@redhat.com> X-Originating-IP: [10.43.160.103] X-ClientProxiedBy: EX13D34UWA003.ant.amazon.com (10.43.160.69) To EX13D28EUC003.ant.amazon.com (10.43.164.43) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 22, 2022 at 04:46:42PM +0100, Vitaly Kuznetsov wrote: > CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you can confirm the sender and know the content is safe. > > > > It has been proven on practice that at least Windows Server 2019 tries > using HVCALL_SEND_IPI_EX in 'XMM fast' mode when it has more than 64 vCPUs > and it needs to send an IPI to a vCPU > 63. Similarly to other XMM Fast > hypercalls (HVCALL_FLUSH_VIRTUAL_ADDRESS_{LIST,SPACE}{,_EX}), this > information is missing in TLFS as of 6.0b. Currently, KVM returns an error > (HV_STATUS_INVALID_HYPERCALL_INPUT) and Windows crashes. > > Note, HVCALL_SEND_IPI is a 'standard' fast hypercall (not 'XMM fast') as > all its parameters fit into RDX:R8 and this is handled by KVM correctly. > > Fixes: d8f5537a8816 ("KVM: hyper-v: Advertise support for fast XMM hypercalls") > Signed-off-by: Vitaly Kuznetsov Reviewed-by: Siddharth Chandrasekaran Amazon Development Center Germany GmbH Krausenstr. 38 10117 Berlin Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B Sitz: Berlin Ust-ID: DE 289 237 879