From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:36346 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727599AbeLMJNj (ORCPT ); Thu, 13 Dec 2018 04:13:39 -0500 Date: Thu, 13 Dec 2018 09:13:20 +0000 From: "Dr. David Alan Gilbert" To: David Hildenbrand Cc: Vivek Goyal , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, miklos@szeredi.hu, stefanha@redhat.com, sweil@redhat.com, swhiteho@redhat.com Subject: Re: [PATCH 18/52] virtio-fs: Map cache using the values from the capabilities Message-ID: <20181213091320.GA2313@work-vm> References: <20181210171318.16998-1-vgoyal@redhat.com> <20181210171318.16998-19-vgoyal@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-ID: * David Hildenbrand (david@redhat.com) wrote: > On 10.12.18 18:12, Vivek Goyal wrote: > > Instead of assuming we had the fixed bar for the cache, use the > > value from the capabilities. > > > > Signed-off-by: Dr. David Alan Gilbert > > --- > > fs/fuse/virtio_fs.c | 32 +++++++++++++++++--------------- > > 1 file changed, 17 insertions(+), 15 deletions(-) > > > > diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c > > index 60d496c16841..55bac1465536 100644 > > --- a/fs/fuse/virtio_fs.c > > +++ b/fs/fuse/virtio_fs.c > > @@ -14,11 +14,6 @@ > > #include > > #include "fuse_i.h" > > > > -enum { > > - /* PCI BAR number of the virtio-fs DAX window */ > > - VIRTIO_FS_WINDOW_BAR = 2, > > -}; > > - > > /* List of virtio-fs device instances and a lock for the list */ > > static DEFINE_MUTEX(virtio_fs_mutex); > > static LIST_HEAD(virtio_fs_instances); > > @@ -518,7 +513,7 @@ static int virtio_fs_setup_dax(struct virtio_device *vdev, struct virtio_fs *fs) > > struct dev_pagemap *pgmap; > > struct pci_dev *pci_dev; > > phys_addr_t phys_addr; > > - size_t len; > > + size_t bar_len; > > int ret; > > u8 have_cache, cache_bar; > > u64 cache_offset, cache_len; > > @@ -551,17 +546,13 @@ static int virtio_fs_setup_dax(struct virtio_device *vdev, struct virtio_fs *fs) > > } > > > > /* TODO handle case where device doesn't expose BAR? */ > > For virtio-pmem we decided to not go via BARs as this would effectively > make it only usable for virtio-pci implementers. Instead, we are going > to export the applicable physical device region directly (e.g. > phys_start, phys_size in virtio config), so it is decoupled from PCI > details. Doing the same for virtio-fs would allow e.g. also virtio-ccw > to make eventually use of this. That makes it a very odd looking PCI device; I can see that with virtio-pmem it makes some sense, given that it's job is to expose arbitrary chunks of memory. Dave > > - ret = pci_request_region(pci_dev, VIRTIO_FS_WINDOW_BAR, > > - "virtio-fs-window"); > > + ret = pci_request_region(pci_dev, cache_bar, "virtio-fs-window"); > > if (ret < 0) { > > dev_err(&vdev->dev, "%s: failed to request window BAR\n", > > __func__); > > return ret; > > } > > > > - phys_addr = pci_resource_start(pci_dev, VIRTIO_FS_WINDOW_BAR); > > - len = pci_resource_len(pci_dev, VIRTIO_FS_WINDOW_BAR); > > - > > mi = devm_kzalloc(&pci_dev->dev, sizeof(*mi), GFP_KERNEL); > > if (!mi) > > return -ENOMEM; > > @@ -586,6 +577,17 @@ static int virtio_fs_setup_dax(struct virtio_device *vdev, struct virtio_fs *fs) > > pgmap->ref = &mi->ref; > > pgmap->type = MEMORY_DEVICE_FS_DAX; > > > > + phys_addr = pci_resource_start(pci_dev, cache_bar); > > + bar_len = pci_resource_len(pci_dev, cache_bar); > > + > > + if (cache_offset + cache_len > bar_len) { > > + dev_err(&vdev->dev, > > + "%s: cache bar shorter than cap offset+len\n", > > + __func__); > > + return -EINVAL; > > + } > > + phys_addr += cache_offset; > > + > > /* Ideally we would directly use the PCI BAR resource but > > * devm_memremap_pages() wants its own copy in pgmap. So > > * initialize a struct resource from scratch (only the start > > @@ -594,7 +596,7 @@ static int virtio_fs_setup_dax(struct virtio_device *vdev, struct virtio_fs *fs) > > pgmap->res = (struct resource){ > > .name = "virtio-fs dax window", > > .start = phys_addr, > > - .end = phys_addr + len, > > + .end = phys_addr + cache_len, > > }; > > > > fs->window_kaddr = devm_memremap_pages(&pci_dev->dev, pgmap); > > @@ -607,10 +609,10 @@ static int virtio_fs_setup_dax(struct virtio_device *vdev, struct virtio_fs *fs) > > return ret; > > > > fs->window_phys_addr = phys_addr; > > - fs->window_len = len; > > + fs->window_len = cache_len; > > > > - dev_dbg(&vdev->dev, "%s: window kaddr 0x%px phys_addr 0x%llx len %zu\n", > > - __func__, fs->window_kaddr, phys_addr, len); > > + dev_dbg(&vdev->dev, "%s: cache kaddr 0x%px phys_addr 0x%llx len %llx\n", > > + __func__, fs->window_kaddr, phys_addr, cache_len); > > > > fs->dax_dev = alloc_dax(fs, NULL, &virtio_fs_dax_ops); > > if (!fs->dax_dev) > > > > > -- > > Thanks, > > David / dhildenb -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK