From: "Jonas Pfefferle1" <JPF@zurich.ibm.com>
To: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: anatoly.burakov@intel.com, dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH] vfio: fix sPAPR IOMMU DMA window size
Date: Tue, 8 Aug 2017 09:56:05 +0200 [thread overview]
Message-ID: <OF5FE7D2C3.7A07FEF2-ONC1258176.002B5998-C1258176.002B965F@notes.na.collabserv.com> (raw)
In-Reply-To: <33a0b391-0a97-0392-39c1-377af4196c69@ozlabs.ru>
Alexey Kardashevskiy <aik@ozlabs.ru> wrote on 08/08/2017 09:38:00 AM:
> From: Alexey Kardashevskiy <aik@ozlabs.ru>
> To: Jonas Pfefferle <jpf@zurich.ibm.com>, anatoly.burakov@intel.com
> Cc: dev@dpdk.org
> Date: 08/08/2017 09:38 AM
> Subject: Re: [PATCH] vfio: fix sPAPR IOMMU DMA window size
>
> On 08/08/17 01:11, Jonas Pfefferle wrote:
> > DMA window size needs to be big enough to span all memory segment's
> > physical addresses. We do not need multiple levels of IOMMU tables
> > as we already span ~70TB of physical memory with 16MB hugepages.
> >
> > Signed-off-by: Jonas Pfefferle <jpf@zurich.ibm.com>
> > ---
> > lib/librte_eal/linuxapp/eal/eal_vfio.c | 25 ++++++++++++++++++++++---
> > 1 file changed, 22 insertions(+), 3 deletions(-)
> >
> > diff --git a/lib/librte_eal/linuxapp/eal/eal_vfio.c b/lib/
> librte_eal/linuxapp/eal/eal_vfio.c
> > index 946df7e..8502216 100644
> > --- a/lib/librte_eal/linuxapp/eal/eal_vfio.c
> > +++ b/lib/librte_eal/linuxapp/eal/eal_vfio.c
> > @@ -722,6 +722,18 @@ vfio_type1_dma_map(int vfio_container_fd)
> > return 0;
> > }
> >
> > +static uint64_t
> > +roundup_next_pow2(uint64_t n)
> > +{
> > + uint32_t i;
> > +
> > + n--;
> > + for (i = 1; i < sizeof(n) * CHAR_BIT; i += i)
> > + n |= n >> i;
> > +
> > + return ++n;
> > +}
> > +
>
> wow :)
>
> QEMU does it using __builtin_ctzll() (used below for the page_shift)
> without a loop:
>
> https://git.qemu.org/gitweb.cgi?p=qemu.git;a=blob;f=include/qemu/
> host-
>
utils.h;h=95cf4f4163e50457cdf808263065ca5ef3f935da;hb=f22ab6cb0c47bd2a2785b7d58130949bd7d8d9af#l382
>
>
> Anyway, seems working.
Ok let me fix that :)
>
>
> Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>
>
>
>
> > static int
> > vfio_spapr_dma_map(int vfio_container_fd)
> > {
> > @@ -759,10 +771,12 @@ vfio_spapr_dma_map(int vfio_container_fd)
> > return -1;
> > }
> >
> > - /* calculate window size based on number of hugepages configured */
> > - create.window_size = rte_eal_get_physmem_size();
> > + /* physicaly pages are sorted descending i.e. ms[0].phys_addr is
max */
> > + /* create DMA window from 0 to max(phys_addr + len) */
> > + /* sPAPR requires window size to be a power of 2 */
> > + create.window_size = roundup_next_pow2(ms[0].phys_addr + ms
[0].len);
> > create.page_shift = __builtin_ctzll(ms->hugepage_sz);
> > - create.levels = 2;
> > + create.levels = 1;
> >
> > ret = ioctl(vfio_container_fd, VFIO_IOMMU_SPAPR_TCE_CREATE,
&create);
> > if (ret) {
> > @@ -771,6 +785,11 @@ vfio_spapr_dma_map(int vfio_container_fd)
> > return -1;
> > }
> >
> > + if (create.start_addr != 0) {
> > + RTE_LOG(ERR, EAL, " DMA window start address != 0\n");
> > + return -1;
> > + }
> > +
> > /* map all DPDK segments for DMA. use 1:1 PA to IOVA mapping */
> > for (i = 0; i < RTE_MAX_MEMSEG; i++) {
> > struct vfio_iommu_type1_dma_map dma_map;
> >
>
>
> --
> Alexey
>
next prev parent reply other threads:[~2017-08-08 7:56 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-07 15:11 Jonas Pfefferle
2017-08-08 7:38 ` Alexey Kardashevskiy
2017-08-08 7:56 ` Jonas Pfefferle1 [this message]
2017-08-08 8:27 ` Ananyev, Konstantin
2017-08-08 8:47 ` Jonas Pfefferle1
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=OF5FE7D2C3.7A07FEF2-ONC1258176.002B5998-C1258176.002B965F@notes.na.collabserv.com \
--to=jpf@zurich.ibm.com \
--cc=aik@ozlabs.ru \
--cc=anatoly.burakov@intel.com \
--cc=dev@dpdk.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).