From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id B7947168 for ; Thu, 15 Jul 2021 22:36:38 +0000 (UTC) Received: by linux.microsoft.com (Postfix, from userid 1096) id 78C8120B6C14; Thu, 15 Jul 2021 15:36:38 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 78C8120B6C14 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1626388598; bh=9/Bqa4eOrfdzbB9ODvgnTNZ736Ji7S/0BoMYLEjPLt8=; h=Date:From:To:Cc:Subject:From; b=jWxiZza4LTdrqT1Tw98NAvjSfKdh5KNEiIX62W17JyKoGc/llQyRs08wV2EDv1ap7 xF1QsBhWgQX6B25otNbTsPhBo82Ma7go9NV/Doiqtx7LQwVFnOke9Wzmm6T3bWWc7I xDVEEGoGYR5QJOVhWd3ezJ2aN5YTNUJB8knY/vlk= Date: Thu, 15 Jul 2021 15:36:38 -0700 From: Taylor Stark To: dan.j.williams@intel.com, vishal.l.verma@intel.com, dave.jiang@intel.com, ira.weiny@intel.com Cc: nvdimm@lists.linux.dev, apais@microsoft.com, tyhicks@microsoft.com, jamorris@microsoft.com, benhill@microsoft.com, sunilmut@microsoft.com, grahamwo@microsoft.com, tstark@microsoft.com Subject: [PATCH v2 2/2] virtio-pmem: Set DRIVER_OK status prior to creating pmem region Message-ID: <20210715223638.GA29649@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net> Precedence: bulk X-Mailing-List: nvdimm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Update virtio-pmem to call virtio_device_ready prior to creating the pmem region. Otherwise, the guest may try to access the pmem region prior to the DRIVER_OK status being set. In the case of Hyper-V, the backing pmem file isn't mapped to the guest until the DRIVER_OK status is set. Therefore, attempts to access the pmem region can cause the guest to crash. Hyper-V could map the file earlier, for example at VM creation, but we didn't want to pay the mapping cost if the device is never used. Additionally, it felt weird to allow the guest to access the region prior to the device fully coming online. Signed-off-by: Taylor Stark --- drivers/nvdimm/virtio_pmem.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/nvdimm/virtio_pmem.c b/drivers/nvdimm/virtio_pmem.c index 43c1d835a449..ea9e111f3ea1 100644 --- a/drivers/nvdimm/virtio_pmem.c +++ b/drivers/nvdimm/virtio_pmem.c @@ -91,6 +91,11 @@ static int virtio_pmem_probe(struct virtio_device *vdev) dev_set_drvdata(&vdev->dev, vpmem->nvdimm_bus); + /* Online the device prior to creating a pmem region, to ensure that + * the region is never touched while the device is offline. + */ + virtio_device_ready(vdev); + ndr_desc.res = &res; ndr_desc.numa_node = nid; ndr_desc.flush = async_pmem_flush; @@ -105,6 +110,7 @@ static int virtio_pmem_probe(struct virtio_device *vdev) nd_region->provider_data = dev_to_virtio(nd_region->dev.parent->parent); return 0; out_nd: + vdev->config->reset(vdev); nvdimm_bus_unregister(vpmem->nvdimm_bus); out_vq: vdev->config->del_vqs(vdev); -- 2.32.0