On Mon, Dec 10, 2018 at 9:22 AM Vivek Goyal <vgoyal@xxxxxxxxxx> wrote: > > From: Stefan Hajnoczi <stefanha@xxxxxxxxxx> > > Experimental QEMU code introduces an MMIO BAR for mapping portions of > files in the virtio-fs device. Map this BAR so that FUSE DAX can access > file contents from the host page cache. FUSE DAX sounds terrifying, can you explain a bit more about what this is? > The DAX window is accessed by the fs/dax.c infrastructure and must have > struct pages (at least on x86). Use devm_memremap_pages() to map the > DAX window PCI BAR and allocate struct page. PCI BAR space is not cache coherent, what prevents these pages from being used in paths that would do: object = page_address(pfn_to_page(virtio_fs_pfn)); ...?
