From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:51568 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726578AbeLMJKZ (ORCPT ); Thu, 13 Dec 2018 04:10:25 -0500 Subject: Re: [PATCH 18/52] virtio-fs: Map cache using the values from the capabilities To: Vivek Goyal , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: miklos@szeredi.hu, stefanha@redhat.com, dgilbert@redhat.com, sweil@redhat.com, swhiteho@redhat.com References: <20181210171318.16998-1-vgoyal@redhat.com> <20181210171318.16998-19-vgoyal@redhat.com> From: David Hildenbrand Message-ID: Date: Thu, 13 Dec 2018 10:10:10 +0100 MIME-Version: 1.0 In-Reply-To: <20181210171318.16998-19-vgoyal@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org List-ID: 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. > - 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