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=-13.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 442C0C433F5 for ; Mon, 13 Sep 2021 06:33:38 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DAC4F60F9B for ; Mon, 13 Sep 2021 06:33:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org DAC4F60F9B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id 91A384017A; Mon, 13 Sep 2021 06:33:37 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id pw21MFzpqsDl; Mon, 13 Sep 2021 06:33:36 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp2.osuosl.org (Postfix) with ESMTPS id D477B401EF; Mon, 13 Sep 2021 06:33:35 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 8F578C0011; Mon, 13 Sep 2021 06:33:35 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id 86927C000D for ; Mon, 13 Sep 2021 06:33:34 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id 55D09401EF for ; Mon, 13 Sep 2021 06:33:34 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 7wvnJ0YC0Jp1 for ; Mon, 13 Sep 2021 06:33:33 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by smtp2.osuosl.org (Postfix) with ESMTPS id 21B444017A for ; Mon, 13 Sep 2021 06:33:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1631514811; 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=PhHmbd+vGEUJyrV5DLTBHy+hH4Q8g3MAN2ba0j9CKCQ=; b=MANHO9U4oiKwN99RdF8lY6ILjjTR+NtrlY3VwrCCkYRwlOFHCEviuVhv7cD4L5jkuqPB0J eLPgRSdk8SnoxZc7C97X/gjuCF6crkIzsX2n1CebrKUDbQn/ei5SlN8Tzh9cOsS6uufF8p zO7vB1/Pra9JLCdvoQUo2PKTnEY2Lro= Received: from mail-ed1-f70.google.com (mail-ed1-f70.google.com [209.85.208.70]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-556-XPf2RCcfOdKleb7yGlD8fA-1; Mon, 13 Sep 2021 02:33:30 -0400 X-MC-Unique: XPf2RCcfOdKleb7yGlD8fA-1 Received: by mail-ed1-f70.google.com with SMTP id g11-20020a056402090b00b003d114f9cb8aso1961752edz.20 for ; Sun, 12 Sep 2021 23:33:30 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=PhHmbd+vGEUJyrV5DLTBHy+hH4Q8g3MAN2ba0j9CKCQ=; b=Hm+IluEABNf/dFmjXHLEEK8HSHxDbSoQnpV/4+zzjGec2ijpOVoDHhqu8XfxkgJf07 0RwNF2uDDlOMhFpXAUUHFjDPjnEJzGVOu/Q3BZWXX6EFEIGsvZdidA0ZDgklnLsGoJ49 zc9WgXVFXZ0PTxdSwKD4QSbGqEzShr0KuekmrlE0ev91cMQ4i8vYedBZgY3AFkckmLQw 2pddf/L8TfmPdegyltYPpBV7zRqP6nNA8oKoSjP1Br3asKKRX9N8OVk+xbU19wXCcNar Ab3UCLwa9PvU2wn5FXZMDbi0JAgEa12fzPOGGPUrFSktoDeqTMMvKD9N1GeUiagJCmT3 0PvQ== X-Gm-Message-State: AOAM530Jxzb7S0SlquUEkDAI5tYxGUHjt59m4wBeaseAme+sTq/SJKeU pV07sRU8RwU0336JEKQR6Bqi0GbHIHrgcXIdusV+zzWs2R5B7pOv5Zk8L5g4vnW2l9WrWfL/UOn UE35kEdoJLB/5+6SmCeS66aCf4cDsN9maIjI48w728A== X-Received: by 2002:a17:906:919:: with SMTP id i25mr10772244ejd.171.1631514809691; Sun, 12 Sep 2021 23:33:29 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyIZT1R9ojuyk23OwxUJ6uHrkH/wVwqrhLF7z3AcQL8TGKDrdQpFBuRq64gNqFYnqY5oSsbIA== X-Received: by 2002:a17:906:919:: with SMTP id i25mr10772233ejd.171.1631514809559; Sun, 12 Sep 2021 23:33:29 -0700 (PDT) Received: from redhat.com ([2.55.27.174]) by smtp.gmail.com with ESMTPSA id o15sm2917942ejj.10.2021.09.12.23.33.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 12 Sep 2021 23:33:28 -0700 (PDT) Date: Mon, 13 Sep 2021 02:33:25 -0400 From: "Michael S. Tsirkin" To: Jason Wang Subject: Re: [PATCH 7/9] virtio-pci: harden INTX interrupts Message-ID: <20210913022824-mutt-send-email-mst@kernel.org> References: <20210913055353.35219-1-jasowang@redhat.com> <20210913055353.35219-8-jasowang@redhat.com> MIME-Version: 1.0 In-Reply-To: <20210913055353.35219-8-jasowang@redhat.com> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mst@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline Cc: konrad.wilk@oracle.com, f.hetzelt@tu-berlin.de, linux-kernel@vger.kernel.org, david.kaplan@amd.com, virtualization@lists.linux-foundation.org X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" On Mon, Sep 13, 2021 at 01:53:51PM +0800, Jason Wang wrote: > This patch tries to make sure the virtio interrupt handler for INTX > won't be called after a reset and before virtio_device_ready(). We > can't use IRQF_NO_AUTOEN since we're using shared interrupt > (IRQF_SHARED). So this patch tracks the INTX enabling status in a new > intx_soft_enabled variable and toggle it during in > vp_disable/enable_vectors(). The INTX interrupt handler will check > intx_soft_enabled before processing the actual interrupt. > > Signed-off-by: Jason Wang Not all that excited about all the memory barriers for something that should be an extremely rare event (for most kernels - literally once per boot). Can't we do better? > --- > drivers/virtio/virtio_pci_common.c | 18 ++++++++++++++++-- > drivers/virtio/virtio_pci_common.h | 1 + > 2 files changed, 17 insertions(+), 2 deletions(-) > > diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c > index 0b9523e6dd39..835197151dc1 100644 > --- a/drivers/virtio/virtio_pci_common.c > +++ b/drivers/virtio/virtio_pci_common.c > @@ -30,8 +30,12 @@ void vp_disable_vectors(struct virtio_device *vdev) > struct virtio_pci_device *vp_dev = to_vp_device(vdev); > int i; > > - if (vp_dev->intx_enabled) > + if (vp_dev->intx_enabled) { > + vp_dev->intx_soft_enabled = false; > + /* ensure the vp_interrupt see this intx_soft_enabled value */ > + smp_wmb(); > synchronize_irq(vp_dev->pci_dev->irq); > + } > > for (i = 0; i < vp_dev->msix_vectors; ++i) > disable_irq(pci_irq_vector(vp_dev->pci_dev, i)); > @@ -43,8 +47,12 @@ void vp_enable_vectors(struct virtio_device *vdev) > struct virtio_pci_device *vp_dev = to_vp_device(vdev); > int i; > > - if (vp_dev->intx_enabled) > + if (vp_dev->intx_enabled) { > + vp_dev->intx_soft_enabled = true; > + /* ensure the vp_interrupt see this intx_soft_enabled value */ > + smp_wmb(); > return; > + } > > for (i = 0; i < vp_dev->msix_vectors; ++i) > enable_irq(pci_irq_vector(vp_dev->pci_dev, i)); > @@ -97,6 +105,12 @@ static irqreturn_t vp_interrupt(int irq, void *opaque) > struct virtio_pci_device *vp_dev = opaque; > u8 isr; > > + if (!vp_dev->intx_soft_enabled) > + return IRQ_NONE; > + > + /* read intx_soft_enabled before read others */ > + smp_rmb(); > + > /* reading the ISR has the effect of also clearing it so it's very > * important to save off the value. */ > isr = ioread8(vp_dev->isr); > diff --git a/drivers/virtio/virtio_pci_common.h b/drivers/virtio/virtio_pci_common.h > index a235ce9ff6a5..3c06e0f92ee4 100644 > --- a/drivers/virtio/virtio_pci_common.h > +++ b/drivers/virtio/virtio_pci_common.h > @@ -64,6 +64,7 @@ struct virtio_pci_device { > /* MSI-X support */ > int msix_enabled; > int intx_enabled; > + bool intx_soft_enabled; > cpumask_var_t *msix_affinity_masks; > /* Name strings for interrupts. This size should be enough, > * and I'm too lazy to allocate each name separately. */ > -- > 2.25.1 _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization