On Fri, Mar 17, 2023 at 10:49:27AM +0100, Eugenio Perez Martin wrote:
On Thu, Mar 16, 2023 at 5:07 PM Stefano Garzarella <sgarzare@xxxxxxxxxx> wrote:On Fri, Mar 3, 2023 at 3:39 PM Eugenio Perez Martin <eperezma@xxxxxxxxxx> wrote: > > On Thu, Mar 2, 2023 at 12:35 PM Stefano Garzarella <sgarzare@xxxxxxxxxx> wrote: > > > > vDPA supports the possibility to use user VA in the iotlb messages. > > So, let's add support for user VA in vringh to use it in the vDPA > > simulators. > > > > Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx> > > --- > > > > Notes: > > v2: > > - replace kmap_atomic() with kmap_local_page() [see previous patch] > > - fix cast warnings when build with W=1 C=1 > > > > include/linux/vringh.h | 5 +- > > drivers/vdpa/mlx5/net/mlx5_vnet.c | 2 +- > > drivers/vdpa/vdpa_sim/vdpa_sim.c | 4 +- > > drivers/vhost/vringh.c | 247 ++++++++++++++++++++++++------ > > 4 files changed, 205 insertions(+), 53 deletions(-) > > [...] > > It seems to me iotlb_translate_va and iotlb_translate_pa are very > similar, their only difference is that the argument is that iov is > iovec instead of bio_vec. And how to fill it, obviously. > > It would be great to merge both functions, only differing with a > conditional on vrh->use_va, or generics, or similar. Or, if following > the style of the rest of vringh code, to provide a callback to fill > iovec (although I like conditional more). > > However I cannot think of an easy way to perform that without long > macros or type erasure. Thank you for pushing me :-) I finally managed to avoid code duplication (partial patch attached, but not yet fully tested). @Jason: with this refactoring I removed copy_to_va/copy_to_pa, so I also avoided getu16_iotlb_va/pa. I will send the full patch in v3, but I would like to get your opinion first ;-) diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c index 0ba3ef809e48..71dd67700e36 100644 --- a/drivers/vhost/vringh.c +++ b/drivers/vhost/vringh.c @@ -1096,8 +1096,7 @@ EXPORT_SYMBOL(vringh_need_notify_kern); static int iotlb_translate(const struct vringh *vrh, u64 addr, u64 len, u64 *translated, - struct bio_vec iov[], - int iov_size, u32 perm) + void *iov, int iov_size, bool iovec, u32 perm)I think this is an improvement, but we're doing type erasure here. I don't think it is a big deal since the function is not exported, it's pretty contained in this file, so I'd ack this version too. I'm just throwing ideas here: a) typedef the union {iovec, bio_vec} and use that type in the parameter. As a drawback, that union feels out of place in this file. Is this the only place where it is needed? I don't see other similar uses in the kernel.
iov_iter has something similar, but they are const pointers, so IIUC it is not supposed to be used to set the bvec contents, just iterate it. Anyway I thought something similar and should be doable, but since it was internal API I went to type erasure.
b) To convert from iov to bio_iov at return The drawback is the extra processing if the compiler is not smart enough to inline it. I prefer the previous one but I didn't want to omit it, just in case.
Yep, I prefer too the previous one, so let's go in that direction for v3 ;-) Thanks, Stefano _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
