| Message ID | 20190514234248.36203-4-farman@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | s390: vfio-ccw fixes | expand |
On 05/14/2019 07:42 PM, Eric Farman wrote: > The pfn_array_alloc_pin routine is doing too much. Today, it does the > alloc of the pfn_array struct and its member arrays, builds the iova > address lists out of a contiguous piece of guest memory, and asks vfio > to pin the resulting pages. > > Let's effectively revert a significant portion of commit 5c1cfb1c3948 > ("vfio: ccw: refactor and improve pfn_array_alloc_pin()") such that we > break pfn_array_alloc_pin() into its component pieces, and have one > routine that allocates/populates the pfn_array structs, and another > that actually pins the memory. In the future, we will be able to > handle scenarios where pinning memory isn't actually appropriate. > > Signed-off-by: Eric Farman <farman@linux.ibm.com> > --- > drivers/s390/cio/vfio_ccw_cp.c | 64 ++++++++++++++++++++++++---------- > 1 file changed, 46 insertions(+), 18 deletions(-) > > diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c > index 41f48b8790bc..60aa784717c5 100644 > --- a/drivers/s390/cio/vfio_ccw_cp.c > +++ b/drivers/s390/cio/vfio_ccw_cp.c > @@ -50,28 +50,25 @@ struct ccwchain { > }; > > /* > - * pfn_array_alloc_pin() - alloc memory for PFNs, then pin user pages in memory > + * pfn_array_alloc() - alloc memory for PFNs > * @pa: pfn_array on which to perform the operation > - * @mdev: the mediated device to perform pin/unpin operations > * @iova: target guest physical address > * @len: number of bytes that should be pinned from @iova > * > - * Attempt to allocate memory for PFNs, and pin user pages in memory. > + * Attempt to allocate memory for PFNs. > * > * Usage of pfn_array: > * We expect (pa_nr == 0) and (pa_iova_pfn == NULL), any field in > * this structure will be filled in by this function. > * > * Returns: > - * Number of pages pinned on success. > - * If @pa->pa_nr is not 0, or @pa->pa_iova_pfn is not NULL initially, > - * returns -EINVAL. > - * If no pages were pinned, returns -errno. > + * 0 if PFNs are allocated > + * -EINVAL if pa->pa_nr is not initially zero, or pa->pa_iova_pfn is not NULL > + * -ENOMEM if alloc failed > */ > -static int pfn_array_alloc_pin(struct pfn_array *pa, struct device *mdev, > - u64 iova, unsigned int len) > +static int pfn_array_alloc(struct pfn_array *pa, u64 iova, unsigned int len) > { > - int i, ret = 0; > + int i; > > if (!len) > return 0; > @@ -97,6 +94,22 @@ static int pfn_array_alloc_pin(struct pfn_array *pa, struct device *mdev, > for (i = 1; i < pa->pa_nr; i++) > pa->pa_iova_pfn[i] = pa->pa_iova_pfn[i - 1] + 1; > > + return 0; > +} > + > +/* > + * pfn_array_pin() - Pin user pages in memory > + * @pa: pfn_array on which to perform the operation > + * @mdev: the mediated device to perform pin operations > + * > + * Returns number of pages pinned upon success. > + * If the pin request partially succeeds, or fails completely, > + * all pages are left unpinned and a negative error value is returned. > + */ > +static int pfn_array_pin(struct pfn_array *pa, struct device *mdev) > +{ > + int ret = 0; > + > ret = vfio_pin_pages(mdev, pa->pa_iova_pfn, pa->pa_nr, > IOMMU_READ | IOMMU_WRITE, pa->pa_pfn); > > @@ -112,8 +125,6 @@ static int pfn_array_alloc_pin(struct pfn_array *pa, struct device *mdev, > > err_out: > pa->pa_nr = 0; > - kfree(pa->pa_iova_pfn); > - pa->pa_iova_pfn = NULL; > > return ret; > } > @@ -121,7 +132,9 @@ static int pfn_array_alloc_pin(struct pfn_array *pa, struct device *mdev, > /* Unpin the pages before releasing the memory. */ > static void pfn_array_unpin_free(struct pfn_array *pa, struct device *mdev) > { > - vfio_unpin_pages(mdev, pa->pa_iova_pfn, pa->pa_nr); > + /* Only unpin if any pages were pinned to begin with */ > + if (pa->pa_nr) > + vfio_unpin_pages(mdev, pa->pa_iova_pfn, pa->pa_nr); > pa->pa_nr = 0; > kfree(pa->pa_iova_pfn); > } > @@ -209,10 +222,16 @@ static long copy_from_iova(struct device *mdev, > int i, ret; > unsigned long l, m; > > - ret = pfn_array_alloc_pin(&pa, mdev, iova, n); > - if (ret <= 0) > + ret = pfn_array_alloc(&pa, iova, n); > + if (ret < 0) > return ret; > > + ret = pfn_array_pin(&pa, mdev); > + if (ret < 0) { > + pfn_array_unpin_free(&pa, mdev); > + return ret; > + } > + > l = n; > for (i = 0; i < pa.pa_nr; i++) { > from = pa.pa_pfn[i] << PAGE_SHIFT; > @@ -559,7 +578,11 @@ static int ccwchain_fetch_direct(struct ccwchain *chain, > if (ret) > goto out_init; > > - ret = pfn_array_alloc_pin(pat->pat_pa, cp->mdev, ccw->cda, ccw->count); > + ret = pfn_array_alloc(pat->pat_pa, ccw->cda, ccw->count); > + if (ret < 0) > + goto out_unpin; > + > + ret = pfn_array_pin(pat->pat_pa, cp->mdev); > if (ret < 0) > goto out_unpin; > > @@ -589,6 +612,7 @@ static int ccwchain_fetch_idal(struct ccwchain *chain, > { > struct ccw1 *ccw; > struct pfn_array_table *pat; > + struct pfn_array *pa; > unsigned long *idaws; > u64 idaw_iova; > unsigned int idaw_nr, idaw_len; > @@ -627,9 +651,13 @@ static int ccwchain_fetch_idal(struct ccwchain *chain, > > for (i = 0; i < idaw_nr; i++) { > idaw_iova = *(idaws + i); > + pa = pat->pat_pa + i; > + > + ret = pfn_array_alloc(pa, idaw_iova, 1); > + if (ret < 0) > + goto out_free_idaws; > > - ret = pfn_array_alloc_pin(pat->pat_pa + i, cp->mdev, > - idaw_iova, 1); > + ret = pfn_array_pin(pa, cp->mdev); > if (ret < 0) > goto out_free_idaws; > } > Reviewed-by: Farhan Ali <alifm@linux.ibm.com>
diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c index 41f48b8790bc..60aa784717c5 100644 --- a/drivers/s390/cio/vfio_ccw_cp.c +++ b/drivers/s390/cio/vfio_ccw_cp.c @@ -50,28 +50,25 @@ struct ccwchain { }; /* - * pfn_array_alloc_pin() - alloc memory for PFNs, then pin user pages in memory + * pfn_array_alloc() - alloc memory for PFNs * @pa: pfn_array on which to perform the operation - * @mdev: the mediated device to perform pin/unpin operations * @iova: target guest physical address * @len: number of bytes that should be pinned from @iova * - * Attempt to allocate memory for PFNs, and pin user pages in memory. + * Attempt to allocate memory for PFNs. * * Usage of pfn_array: * We expect (pa_nr == 0) and (pa_iova_pfn == NULL), any field in * this structure will be filled in by this function. * * Returns: - * Number of pages pinned on success. - * If @pa->pa_nr is not 0, or @pa->pa_iova_pfn is not NULL initially, - * returns -EINVAL. - * If no pages were pinned, returns -errno. + * 0 if PFNs are allocated + * -EINVAL if pa->pa_nr is not initially zero, or pa->pa_iova_pfn is not NULL + * -ENOMEM if alloc failed */ -static int pfn_array_alloc_pin(struct pfn_array *pa, struct device *mdev, - u64 iova, unsigned int len) +static int pfn_array_alloc(struct pfn_array *pa, u64 iova, unsigned int len) { - int i, ret = 0; + int i; if (!len) return 0; @@ -97,6 +94,22 @@ static int pfn_array_alloc_pin(struct pfn_array *pa, struct device *mdev, for (i = 1; i < pa->pa_nr; i++) pa->pa_iova_pfn[i] = pa->pa_iova_pfn[i - 1] + 1; + return 0; +} + +/* + * pfn_array_pin() - Pin user pages in memory + * @pa: pfn_array on which to perform the operation + * @mdev: the mediated device to perform pin operations + * + * Returns number of pages pinned upon success. + * If the pin request partially succeeds, or fails completely, + * all pages are left unpinned and a negative error value is returned. + */ +static int pfn_array_pin(struct pfn_array *pa, struct device *mdev) +{ + int ret = 0; + ret = vfio_pin_pages(mdev, pa->pa_iova_pfn, pa->pa_nr, IOMMU_READ | IOMMU_WRITE, pa->pa_pfn); @@ -112,8 +125,6 @@ static int pfn_array_alloc_pin(struct pfn_array *pa, struct device *mdev, err_out: pa->pa_nr = 0; - kfree(pa->pa_iova_pfn); - pa->pa_iova_pfn = NULL; return ret; } @@ -121,7 +132,9 @@ static int pfn_array_alloc_pin(struct pfn_array *pa, struct device *mdev, /* Unpin the pages before releasing the memory. */ static void pfn_array_unpin_free(struct pfn_array *pa, struct device *mdev) { - vfio_unpin_pages(mdev, pa->pa_iova_pfn, pa->pa_nr); + /* Only unpin if any pages were pinned to begin with */ + if (pa->pa_nr) + vfio_unpin_pages(mdev, pa->pa_iova_pfn, pa->pa_nr); pa->pa_nr = 0; kfree(pa->pa_iova_pfn); } @@ -209,10 +222,16 @@ static long copy_from_iova(struct device *mdev, int i, ret; unsigned long l, m; - ret = pfn_array_alloc_pin(&pa, mdev, iova, n); - if (ret <= 0) + ret = pfn_array_alloc(&pa, iova, n); + if (ret < 0) return ret; + ret = pfn_array_pin(&pa, mdev); + if (ret < 0) { + pfn_array_unpin_free(&pa, mdev); + return ret; + } + l = n; for (i = 0; i < pa.pa_nr; i++) { from = pa.pa_pfn[i] << PAGE_SHIFT; @@ -559,7 +578,11 @@ static int ccwchain_fetch_direct(struct ccwchain *chain, if (ret) goto out_init; - ret = pfn_array_alloc_pin(pat->pat_pa, cp->mdev, ccw->cda, ccw->count); + ret = pfn_array_alloc(pat->pat_pa, ccw->cda, ccw->count); + if (ret < 0) + goto out_unpin; + + ret = pfn_array_pin(pat->pat_pa, cp->mdev); if (ret < 0) goto out_unpin; @@ -589,6 +612,7 @@ static int ccwchain_fetch_idal(struct ccwchain *chain, { struct ccw1 *ccw; struct pfn_array_table *pat; + struct pfn_array *pa; unsigned long *idaws; u64 idaw_iova; unsigned int idaw_nr, idaw_len; @@ -627,9 +651,13 @@ static int ccwchain_fetch_idal(struct ccwchain *chain, for (i = 0; i < idaw_nr; i++) { idaw_iova = *(idaws + i); + pa = pat->pat_pa + i; + + ret = pfn_array_alloc(pa, idaw_iova, 1); + if (ret < 0) + goto out_free_idaws; - ret = pfn_array_alloc_pin(pat->pat_pa + i, cp->mdev, - idaw_iova, 1); + ret = pfn_array_pin(pa, cp->mdev); if (ret < 0) goto out_free_idaws; }
The pfn_array_alloc_pin routine is doing too much. Today, it does the alloc of the pfn_array struct and its member arrays, builds the iova address lists out of a contiguous piece of guest memory, and asks vfio to pin the resulting pages. Let's effectively revert a significant portion of commit 5c1cfb1c3948 ("vfio: ccw: refactor and improve pfn_array_alloc_pin()") such that we break pfn_array_alloc_pin() into its component pieces, and have one routine that allocates/populates the pfn_array structs, and another that actually pins the memory. In the future, we will be able to handle scenarios where pinning memory isn't actually appropriate. Signed-off-by: Eric Farman <farman@linux.ibm.com> --- drivers/s390/cio/vfio_ccw_cp.c | 64 ++++++++++++++++++++++++---------- 1 file changed, 46 insertions(+), 18 deletions(-)