Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Fri, 14 Apr 2023 16:17:35 +0100
From:   Jean-Philippe Brucker <jean-philippe@linaro.org>
To:     Akihiko Odaki <akihiko.odaki@daynix.com>
Cc:     Eric Auger <eric.auger@redhat.com>,
        virtio-dev@lists.oasis-open.org,
        virtualization@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org, qemu-devel@nongnu.org
Subject: Re: virtio-iommu hotplug issue
Message-ID: <20230414151735.GA4145625@myrica>
References: <15bf1b00-3aa0-973a-3a86-3fa5c4d41d2c@daynix.com>
 <20230413104041.GA3295191@myrica>
 <c6fb5a06-aa7e-91f9-7001-f456b2769595@daynix.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <c6fb5a06-aa7e-91f9-7001-f456b2769595@daynix.com>
Precedence: bulk

On Thu, Apr 13, 2023 at 08:01:54PM +0900, Akihiko Odaki wrote:
> Yes, that's right. The guest can dynamically create and delete VFs. The
> device is emulated by QEMU: igb, an Intel NIC recently added to QEMU and
> projected to be released as part of QEMU 8.0.

Ah great, that's really useful, I'll add it to my tests

> > Yes, I think this is an issue in the virtio-iommu driver, which should be
> > sending a DETACH request when the VF is disabled, likely from
> > viommu_release_device(). I'll work on a fix unless you would like to do it
> 
> It will be nice if you prepare a fix. I will test your patch with my
> workload if you share it with me.

I sent a fix:
https://lore.kernel.org/linux-iommu/20230414150744.562456-1-jean-philippe@linaro.org/

Thank you for reporting this, it must have been annoying to debug

Thanks,
Jean