From patchwork Thu Jul 15 22:35:05 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Taylor Stark X-Patchwork-Id: 12381183 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 7655D168 for ; Thu, 15 Jul 2021 22:35:05 +0000 (UTC) Received: by linux.microsoft.com (Postfix, from userid 1096) id 1D9ED20B6C14; Thu, 15 Jul 2021 15:35:05 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 1D9ED20B6C14 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1626388505; bh=0Y9wwxU/DVdA5BAO3tI9BpMGIlkLOOdAAoja4Q5yrk0=; h=Date:From:To:Cc:Subject:From; b=WjfqvAakEex0agxi0BhGpQBN9bjE+A7hui7gQWH8jTpVj1IVgJTFRKrwrQfVH7rB9 8GxZvo16DXyKcaQgqqafdiQfacGrHzq4fWKJ5rkyzJlO2UMsFuYIqqUUJbCWvWt8u6 walR5vll1M9UfH5uhTpEaiqJ1hqhPe7upgSu/SwY= Date: Thu, 15 Jul 2021 15:35:05 -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 1/2] virtio-pmem: Support PCI BAR-relative addresses Message-ID: <20210715223505.GA29329@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-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Update virtio-pmem to allow for the pmem region to be specified in either guest absolute terms or as a PCI BAR-relative address. This is required to support virtio-pmem in Hyper-V, since Hyper-V only allows PCI devices to operate on PCI memory ranges defined via BARs. Virtio-pmem will check for a shared memory window and use that if found, else it will fallback to using the guest absolute addresses in virtio_pmem_config. This was chosen over defining a new feature bit, since it's similar to how virtio-fs is configured. Signed-off-by: Taylor Stark --- drivers/nvdimm/virtio_pmem.c | 21 +++++++++++++++++---- drivers/nvdimm/virtio_pmem.h | 3 +++ 2 files changed, 20 insertions(+), 4 deletions(-) diff --git a/drivers/nvdimm/virtio_pmem.c b/drivers/nvdimm/virtio_pmem.c index 726c7354d465..43c1d835a449 100644 --- a/drivers/nvdimm/virtio_pmem.c +++ b/drivers/nvdimm/virtio_pmem.c @@ -37,6 +37,8 @@ static int virtio_pmem_probe(struct virtio_device *vdev) struct virtio_pmem *vpmem; struct resource res; int err = 0; + bool have_shm_region; + struct virtio_shm_region pmem_region; if (!vdev->config->get) { dev_err(&vdev->dev, "%s failure: config access disabled\n", @@ -58,10 +60,21 @@ static int virtio_pmem_probe(struct virtio_device *vdev) goto out_err; } - virtio_cread_le(vpmem->vdev, struct virtio_pmem_config, - start, &vpmem->start); - virtio_cread_le(vpmem->vdev, struct virtio_pmem_config, - size, &vpmem->size); + /* Retrieve the pmem device's address and size. It may have been supplied + * as a PCI BAR-relative shared memory region, or as a guest absolute address. + */ + have_shm_region = virtio_get_shm_region(vpmem->vdev, &pmem_region, + VIRTIO_PMEM_SHMCAP_ID_PMEM_REGION); + + if (have_shm_region) { + vpmem->start = pmem_region.addr; + vpmem->size = pmem_region.len; + } else { + virtio_cread_le(vpmem->vdev, struct virtio_pmem_config, + start, &vpmem->start); + virtio_cread_le(vpmem->vdev, struct virtio_pmem_config, + size, &vpmem->size); + } res.start = vpmem->start; res.end = vpmem->start + vpmem->size - 1; diff --git a/drivers/nvdimm/virtio_pmem.h b/drivers/nvdimm/virtio_pmem.h index 0dddefe594c4..62bb564e81cb 100644 --- a/drivers/nvdimm/virtio_pmem.h +++ b/drivers/nvdimm/virtio_pmem.h @@ -50,6 +50,9 @@ struct virtio_pmem { __u64 size; }; +/* For the id field in virtio_pci_shm_cap */ +#define VIRTIO_PMEM_SHMCAP_ID_PMEM_REGION 0 + void virtio_pmem_host_ack(struct virtqueue *vq); int async_pmem_flush(struct nd_region *nd_region, struct bio *bio); #endif