netdev - Re: [PATCH v8 10/15] octeontx2-af: Reconfig MSIX base with IOVA

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 10 Oct 2018 13:05:47 +0530
From:   Sunil Kovvuri <sunil.kovvuri@...il.com>
To:     Arnd Bergmann <arnd@...db.de>
Cc:     Linux Netdev List <netdev@...r.kernel.org>,
        "David S. Miller" <davem@...emloft.net>, linux-soc@...r.kernel.org,
        Geetha sowjanya <gakula@...vell.com>,
        Sunil Goutham <sgoutham@...vell.com>
Subject: Re: [PATCH v8 10/15] octeontx2-af: Reconfig MSIX base with IOVA

On Tue, Oct 9, 2018 at 5:30 PM Arnd Bergmann <arnd@...db.de> wrote:
>
> On Tue, Oct 9, 2018 at 11:20 AM Sunil Kovvuri <sunil.kovvuri@...il.com> wrote:
> >
> > On Tue, Oct 9, 2018 at 1:27 PM Arnd Bergmann <arnd@...db.de> wrote:
> > >
> > > On Tue, Oct 9, 2018 at 9:03 AM Sunil Kovvuri <sunil.kovvuri@...il.com> wrote:
> > > > On Mon, Oct 8, 2018 at 5:38 PM Arnd Bergmann <arnd@...db.de> wrote:
> > > > > On Sun, Oct 7, 2018 at 5:01 PM <sunil.kovvuri@...il.com> wrote:
> > > I think if you enable CONFIG_DEBUG_VIRTUAL, the virt_to_page()
> > > above should trigger a warning in
> > >
> > > phys_addr_t __virt_to_phys(unsigned long x)
> > > {
> > >         WARN(!__is_lm_address(x),
> > >              "virt_to_phys used for non-linear address: %pK (%pS)\n",
> > >               (void *)x,
> > >               (void *)x);
> > >
> > >         return __virt_to_phys_nodebug(x);
> > > }
> > >
> > > Can you verify that?
> > >
> > >         Arnd
> >
> > No, it isn't, as for 64bit systems CONFIG_SPARSEMEM_VMEMMAP is enabled.
>
> But that is also user-selectable, right? It still seems to be really
> fragile to rely on non-documented behavior of virt_to_phys()
> here, if that only works for some configurations.
>
> > But is there any alternative to what is being done ?
>
> I'm not completely sure, but there may be a way to do this correctly
> using the iommu API instead of the dma-mapping API. What you do
> here is fairly rare, but not unprecedented.
>
>       Arnd

After further checking the only way i found is using dma_map_resource() which
accepts physical address and creates a mapping. Will test and submit next series
with the changes.

Thanks,
Sunil.