From 01aa26c672c0eb771de4aaa2a8ccf6055778887b Mon Sep 17 00:00:00 2001 From: Eric Farman Date: Thu, 6 Jun 2019 22:28:31 +0200 Subject: [PATCH] s390/cio: Combine direct and indirect CCW paths With both the direct-addressed and indirect-addressed CCW paths simplified to this point, the amount of shared code between them is (hopefully) more easily visible. Move the processing of IDA-specific bits into the direct-addressed path, and add some useful commentary of what the individual pieces are doing. This allows us to remove the entire ccwchain_fetch_idal() routine and maintain a single function for any non-TIC CCW. Signed-off-by: Eric Farman Reviewed-by: Cornelia Huck Message-Id: <20190606202831.44135-10-farman@linux.ibm.com> Signed-off-by: Cornelia Huck --- drivers/s390/cio/vfio_ccw_cp.c | 115 +++++++++++---------------------- 1 file changed, 39 insertions(+), 76 deletions(-) diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c index 8205d0b527fc..90d86e1354c1 100644 --- a/drivers/s390/cio/vfio_ccw_cp.c +++ b/drivers/s390/cio/vfio_ccw_cp.c @@ -534,10 +534,12 @@ static int ccwchain_fetch_direct(struct ccwchain *chain, { struct ccw1 *ccw; struct pfn_array *pa; + u64 iova; unsigned long *idaws; int ret; int bytes = 1; - int idaw_nr; + int idaw_nr, idal_len; + int i; ccw = chain->ch_ccw + idx; @@ -545,7 +547,17 @@ static int ccwchain_fetch_direct(struct ccwchain *chain, bytes = ccw->count; /* Calculate size of IDAL */ - idaw_nr = idal_nr_words((void *)(u64)ccw->cda, bytes); + 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(cp->mdev, &iova, ccw->cda, sizeof(iova)); + if (ret) + return ret; + } else { + iova = ccw->cda; + } + idaw_nr = idal_nr_words((void *)iova, bytes); + idal_len = idaw_nr * sizeof(*idaws); /* Allocate an IDAL from host storage */ idaws = kcalloc(idaw_nr, sizeof(*idaws), GFP_DMA | GFP_KERNEL); @@ -555,15 +567,36 @@ static int ccwchain_fetch_direct(struct ccwchain *chain, } /* - * Pin data page(s) in memory. - * The number of pages actually is the count of the idaws which will be - * needed when translating a direct ccw to a idal ccw. + * Allocate an array of pfn's for pages to pin/translate. + * The number of pages is actually the count of the idaws + * required for the data transfer, since we only only support + * 4K IDAWs today. */ pa = chain->ch_pa + idx; - ret = pfn_array_alloc(pa, ccw->cda, bytes); + ret = pfn_array_alloc(pa, iova, bytes); if (ret < 0) goto out_free_idaws; + if (ccw_is_idal(ccw)) { + /* Copy guest IDAL into host IDAL */ + ret = copy_from_iova(cp->mdev, idaws, ccw->cda, idal_len); + if (ret) + goto out_unpin; + + /* + * Copy guest IDAWs into pfn_array, in case the memory they + * occupy is not contiguous. + */ + for (i = 0; i < idaw_nr; i++) + pa->pa_iova_pfn[i] = idaws[i] >> PAGE_SHIFT; + } else { + /* + * No action is required here; the iova addresses in pfn_array + * were initialized sequentially in pfn_array_alloc() beginning + * with the contents of ccw->cda. + */ + } + if (ccw_does_data_transfer(ccw)) { ret = pfn_array_pin(pa, cp->mdev); if (ret < 0) @@ -589,73 +622,6 @@ static int ccwchain_fetch_direct(struct ccwchain *chain, return ret; } -static int ccwchain_fetch_idal(struct ccwchain *chain, - int idx, - struct channel_program *cp) -{ - struct ccw1 *ccw; - struct pfn_array *pa; - unsigned long *idaws; - u64 idaw_iova; - unsigned int idaw_nr, idaw_len; - int i, ret; - int bytes = 1; - - ccw = chain->ch_ccw + idx; - - if (ccw->count) - bytes = ccw->count; - - /* Calculate size of idaws. */ - ret = copy_from_iova(cp->mdev, &idaw_iova, ccw->cda, sizeof(idaw_iova)); - if (ret) - return ret; - idaw_nr = idal_nr_words((void *)(idaw_iova), bytes); - idaw_len = idaw_nr * sizeof(*idaws); - - /* Pin data page(s) in memory. */ - pa = chain->ch_pa + idx; - ret = pfn_array_alloc(pa, idaw_iova, bytes); - if (ret) - goto out_init; - - /* Translate idal ccw to use new allocated idaws. */ - idaws = kzalloc(idaw_len, GFP_DMA | GFP_KERNEL); - if (!idaws) { - ret = -ENOMEM; - goto out_unpin; - } - - ret = copy_from_iova(cp->mdev, idaws, ccw->cda, idaw_len); - if (ret) - goto out_free_idaws; - - ccw->cda = virt_to_phys(idaws); - - for (i = 0; i < idaw_nr; i++) - pa->pa_iova_pfn[i] = idaws[i] >> PAGE_SHIFT; - - if (ccw_does_data_transfer(ccw)) { - ret = pfn_array_pin(pa, cp->mdev); - if (ret < 0) - goto out_free_idaws; - } else { - pa->pa_nr = 0; - } - - pfn_array_idal_create_words(pa, idaws); - - return 0; - -out_free_idaws: - kfree(idaws); -out_unpin: - pfn_array_unpin_free(pa, cp->mdev); -out_init: - ccw->cda = 0; - return ret; -} - /* * Fetch one ccw. * To reduce memory copy, we'll pin the cda page in memory, @@ -671,9 +637,6 @@ static int ccwchain_fetch_one(struct ccwchain *chain, if (ccw_is_tic(ccw)) return ccwchain_fetch_tic(chain, idx, cp); - if (ccw_is_idal(ccw)) - return ccwchain_fetch_idal(chain, idx, cp); - return ccwchain_fetch_direct(chain, idx, cp); }