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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 9291FC28CC0 for ; Thu, 30 May 2019 18:46:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 68D9325FDE for ; Thu, 30 May 2019 18:46:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726674AbfE3SqD (ORCPT ); Thu, 30 May 2019 14:46:03 -0400 Received: from mga12.intel.com ([192.55.52.136]:20607 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726079AbfE3SqD (ORCPT ); Thu, 30 May 2019 14:46:03 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 30 May 2019 11:46:02 -0700 X-ExtLoop1: 1 Received: from sjchrist-coffee.jf.intel.com (HELO linux.intel.com) ([10.54.74.36]) by orsmga001.jf.intel.com with ESMTP; 30 May 2019 11:46:02 -0700 Date: Thu, 30 May 2019 11:46:02 -0700 From: Sean Christopherson To: Luwei Kang Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, pbonzini@redhat.com, rkrcmar@redhat.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, x86@kernel.org Subject: Re: [PATCH] KVM: LAPIC: Do not mask the local interrupts when LAPIC is sw disabled Message-ID: <20190530184602.GD23930@linux.intel.com> References: <1558435455-233679-1-git-send-email-luwei.kang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1558435455-233679-1-git-send-email-luwei.kang@intel.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 21, 2019 at 06:44:15PM +0800, Luwei Kang wrote: > The current code will mask all the local interrupts in the local > vector table when the LAPIC is disabled by SVR (Spurious-Interrupt > Vector Register) "APIC Software Enable/Disable" flag (bit8). > This may block local interrupt be delivered to target vCPU > even if LAPIC is enabled by set SVR (bit8 == 1) after. The current code aligns with the SDM, which states: Local APIC State After It Has Been Software Disabled When the APIC software enable/disable flag in the spurious interrupt vector register has been explicitly cleared (as opposed to being cleared during a power up or reset), the local APIC is temporarily disabled. The operation and response of a local APIC while in this software- disabled state is as follows: - The mask bits for all the LVT entries are set. Attempts to reset these bits will be ignored.