| Message ID | 1525461967-32174-5-git-send-email-paul.durrant@citrix.com |
|---|---|
| State | New |
| Headers | show |
| Series | xen_disk: legacy code removal and cleanup | expand |
On Fri, May 04, 2018 at 08:26:03PM +0100, Paul Durrant wrote: > Not all Xen environments support the xengnttab_grant_copy() operation. > E.g. where the OS is FreeBSD or Xen is older than 4.8.0. > > This patch introduces an emulation of that operation using > xengnttab_map_domain_grant_refs() and memcpy() for those environments. > > Signed-off-by: Paul Durrant <paul.durrant@citrix.com> > --- The patch looks ok, but since patch 1 is going to be change, this one is going to need to be change as well.
> -----Original Message----- > From: Anthony PERARD [mailto:anthony.perard@citrix.com] > Sent: 16 May 2018 15:31 > To: Paul Durrant <Paul.Durrant@citrix.com> > Cc: xen-devel@lists.xenproject.org; qemu-block@nongnu.org; qemu- > devel@nongnu.org; Stefano Stabellini <sstabellini@kernel.org> > Subject: Re: [PATCH v3 4/8] xen_backend: add an emulation of grant copy > > On Fri, May 04, 2018 at 08:26:03PM +0100, Paul Durrant wrote: > > Not all Xen environments support the xengnttab_grant_copy() operation. > > E.g. where the OS is FreeBSD or Xen is older than 4.8.0. > > > > This patch introduces an emulation of that operation using > > xengnttab_map_domain_grant_refs() and memcpy() for those > environments. > > > > Signed-off-by: Paul Durrant <paul.durrant@citrix.com> > > --- > > The patch looks ok, but since patch 1 is going to be change, this one is > going to need to be change as well. > Sure. Thanks for the review. Paul > -- > Anthony PERARD
diff --git a/hw/xen/xen_backend.c b/hw/xen/xen_backend.c index 50412d6..3c3fc2c 100644 --- a/hw/xen/xen_backend.c +++ b/hw/xen/xen_backend.c @@ -146,6 +146,55 @@ void xen_be_unmap_grant_refs(struct XenDevice *xendev, void *ptr, } } +static int compat_copy_grant_refs(struct XenDevice *xendev, + bool to_domain, + XenGrantCopySegment segs[], + unsigned int nr_segs) +{ + uint32_t *refs = g_new(uint32_t, nr_segs); + int prot = to_domain ? PROT_WRITE : PROT_READ; + void *pages; + unsigned int i; + + for (i = 0; i < nr_segs; i++) { + XenGrantCopySegment *seg = &segs[i]; + + refs[i] = to_domain ? + seg->dest.foreign.ref : seg->source.foreign.ref; + } + + pages = xengnttab_map_domain_grant_refs(xendev->gnttabdev, nr_segs, + xen_domid, refs, prot); + if (!pages) { + xen_pv_printf(xendev, 0, + "xengnttab_map_domain_grant_refs failed: %s\n", + strerror(errno)); + g_free(refs); + return -1; + } + + for (i = 0; i < nr_segs; i++) { + XenGrantCopySegment *seg = &segs[i]; + void *page = pages + (i * XC_PAGE_SIZE); + + if (to_domain) { + memcpy(page + seg->dest.foreign.offset, seg->source.virt, + seg->len); + } else { + memcpy(seg->dest.virt, page + seg->source.foreign.offset, + seg->len); + } + } + + if (xengnttab_unmap(xendev->gnttabdev, pages, nr_segs)) { + xen_pv_printf(xendev, 0, "xengnttab_unmap failed: %s\n", + strerror(errno)); + } + + g_free(refs); + return 0; +} + int xen_be_copy_grant_refs(struct XenDevice *xendev, bool to_domain, XenGrantCopySegment segs[], @@ -157,6 +206,10 @@ int xen_be_copy_grant_refs(struct XenDevice *xendev, assert(xendev->ops->flags & DEVOPS_FLAG_NEED_GNTDEV); + if (!xen_feature_grant_copy) { + return compat_copy_grant_refs(xendev, to_domain, segs, nr_segs); + } + xengnttab_segs = g_new0(xengnttab_grant_copy_segment_t, nr_segs); for (i = 0; i < nr_segs; i++) {
Not all Xen environments support the xengnttab_grant_copy() operation. E.g. where the OS is FreeBSD or Xen is older than 4.8.0. This patch introduces an emulation of that operation using xengnttab_map_domain_grant_refs() and memcpy() for those environments. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> --- Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Anthony Perard <anthony.perard@citrix.com> v2: - New in v2 --- hw/xen/xen_backend.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+)