On 11/21/22 4:40 PM, Eric Farman wrote: > It was suggested [1] that we replace the old copy_from_iova() routine > (which pins a page, does a memcpy, and unpins the page) with the > newer vfio_dma_rw() interface. > > This has a modest improvement in the overall time spent through the > fsm_io_request() path, and simplifies some of the code to boot. > > [1] https://lore.kernel.org/r/20220706170553.GK693670@xxxxxxxxxx/ > > Suggested-by: Jason Gunthorpe <jgg@xxxxxxxxxx> > Signed-off-by: Eric Farman <farman@xxxxxxxxxxxxx> Nice cleanup. Reviewed-by: Matthew Rosato <mjrosato@xxxxxxxxxxxxx> > --- > drivers/s390/cio/vfio_ccw_cp.c | 56 +++------------------------------- > 1 file changed, 5 insertions(+), 51 deletions(-) > > diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c > index 3a11132b1685..1eacbb8dc860 100644 > --- a/drivers/s390/cio/vfio_ccw_cp.c > +++ b/drivers/s390/cio/vfio_ccw_cp.c > @@ -228,51 +228,6 @@ static void convert_ccw0_to_ccw1(struct ccw1 *source, unsigned long len) > } > } > > -/* > - * Within the domain (@vdev), copy @n bytes from a guest physical > - * address (@iova) to a host physical address (@to). > - */ > -static long copy_from_iova(struct vfio_device *vdev, void *to, u64 iova, > - unsigned long n) > -{ > - struct page_array pa = {0}; > - int i, ret; > - unsigned long l, m; > - > - ret = page_array_alloc(&pa, iova, n); > - if (ret < 0) > - return ret; > - > - ret = page_array_pin(&pa, vdev); > - if (ret < 0) { > - page_array_unpin_free(&pa, vdev); > - return ret; > - } > - > - l = n; > - for (i = 0; i < pa.pa_nr; i++) { > - void *from = kmap_local_page(pa.pa_page[i]); > - > - m = PAGE_SIZE; > - if (i == 0) { > - from += iova & (PAGE_SIZE - 1); > - m -= iova & (PAGE_SIZE - 1); > - } > - > - m = min(l, m); > - memcpy(to + (n - l), from, m); > - kunmap_local(from); > - > - l -= m; > - if (l == 0) > - break; > - } > - > - page_array_unpin_free(&pa, vdev); > - > - return l; > -} > - > /* > * Helpers to operate ccwchain. > */ > @@ -471,10 +426,9 @@ static int ccwchain_handle_ccw(u32 cda, struct channel_program *cp) > int len, ret; > > /* Copy 2K (the most we support today) of possible CCWs */ > - len = copy_from_iova(vdev, cp->guest_cp, cda, > - CCWCHAIN_LEN_MAX * sizeof(struct ccw1)); > - if (len) > - return len; > + ret = vfio_dma_rw(vdev, cda, cp->guest_cp, CCWCHAIN_LEN_MAX * sizeof(struct ccw1), false); > + if (ret) > + return ret; > > /* Convert any Format-0 CCWs to Format-1 */ > if (!cp->orb.cmd.fmt) > @@ -572,7 +526,7 @@ static int ccwchain_fetch_direct(struct ccwchain *chain, > if (ccw_is_idal(ccw)) { > /* Read first IDAW to see if it's 4K-aligned or not. */ > /* All subsequent IDAws will be 4K-aligned. */ > - ret = copy_from_iova(vdev, &iova, ccw->cda, sizeof(iova)); > + ret = vfio_dma_rw(vdev, ccw->cda, &iova, sizeof(iova), false); > if (ret) > return ret; > } else { > @@ -601,7 +555,7 @@ static int ccwchain_fetch_direct(struct ccwchain *chain, > > if (ccw_is_idal(ccw)) { > /* Copy guest IDAL into host IDAL */ > - ret = copy_from_iova(vdev, idaws, ccw->cda, idal_len); > + ret = vfio_dma_rw(vdev, ccw->cda, idaws, idal_len, false); > if (ret) > goto out_unpin; >
