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 35BDCC433FE for ; Mon, 13 Sep 2021 22:20:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1C002606A5 for ; Mon, 13 Sep 2021 22:20:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237874AbhIMWVY (ORCPT ); Mon, 13 Sep 2021 18:21:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42118 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230042AbhIMWVW (ORCPT ); Mon, 13 Sep 2021 18:21:22 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5C6F2C061574 for ; Mon, 13 Sep 2021 15:20:06 -0700 (PDT) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1631571603; 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: in-reply-to:in-reply-to:references:references; bh=lu0+SbfjHiOcgPZXbw0IysSWeG75SaeBouN1PbDBmZI=; b=hp/7iXGX7n44dTdyvpJTD0IRHoHq9a0+44UxrvH7sj7uEc2jcTE/sD6W0Born2ch6r7j47 FRI6TDz373Dh9wuxQj+1o91yGkz29g7gU3+9zEh4wYppwTnU7j0MMS50rmlo3RQaWX6yKS lnNRuYyou1nlTflakQKHgiirstJKBCX86Cung2232Q8OSQl0pqY2dbO09LZMRHB5Go6FD2 JyLjvKTYkX2IOUOBePxsvCUiTVgDPHldpCYVXPPeI7p0hwGfeC2+1kaJ1PR+8XaNZbTmsa o+/toszLUWIU8X8FWkgIXcdRmuwY2DfQ9AEvqC44rHJeK0J2jJ5Srd5GCPTtCg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1631571603; 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: in-reply-to:in-reply-to:references:references; bh=lu0+SbfjHiOcgPZXbw0IysSWeG75SaeBouN1PbDBmZI=; b=tZec57HziKkqsYs+DDwwW/G25gb73z0LPjbB1zxfZg0e57L+3/rV8t3vA1CzHBLx41dMOI xDfcyYUDC+ffcnBw== To: "Michael S. Tsirkin" Cc: Jason Wang , virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, f.hetzelt@tu-berlin.de, david.kaplan@amd.com, konrad.wilk@oracle.com, Peter Zijlstra , Will Deacon , Boqun Feng , "Paul E. McKenney" Subject: Re: [PATCH 7/9] virtio-pci: harden INTX interrupts In-Reply-To: <20210913175428-mutt-send-email-mst@kernel.org> References: <20210913055353.35219-1-jasowang@redhat.com> <20210913055353.35219-8-jasowang@redhat.com> <875yv4f99j.ffs@tglx> <20210913175428-mutt-send-email-mst@kernel.org> Date: Tue, 14 Sep 2021 00:20:02 +0200 Message-ID: <87y280dsod.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 13 2021 at 18:01, Michael S. Tsirkin wrote: > On Mon, Sep 13, 2021 at 11:36:24PM +0200, Thomas Gleixner wrote: >> >From the interrupt perspective the sequence: >> >> disable_irq(); >> vp_dev->intx_soft_enabled = true; >> enable_irq(); >> >> is perfectly fine as well. Any interrupt arriving during the disabled >> section will be reraised on enable_irq() in hardware because it's a >> level interrupt. Any resulting failure is either a hardware or a >> hypervisor bug. > > yes but it's a shared interrupt. what happens if multiple callers do > this in parallel? Nothing as each caller is serialized vs. itself and its own interrupt handler it cares about. Thanks, tglx