linux-kernel - Re: [PATCH v4 1/2] powerpc/pseries/iommu: Share the per-cpu TCE page with the hypervisor.

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]

Message-Id: <20191204202751.GD5063@oc0525413822.ibm.com>
Date:   Wed, 4 Dec 2019 12:27:51 -0800
From:   Ram Pai <linuxram@...ibm.com>
To:     Leonardo Bras <leonardo@...ux.ibm.com>
Cc:     linuxppc-dev@...ts.ozlabs.org, mpe@...erman.id.au,
        andmike@...ibm.com, mst@...hat.com, aik@...abs.ru,
        mdroth@...ux.vnet.ibm.com, linux-kernel@...r.kernel.org,
        ram.n.pai@...il.com, cai@....pw, tglx@...utronix.de,
        sukadev@...ux.vnet.ibm.com, hch@....de, bauerman@...ux.ibm.com,
        david@...son.dropbear.id.au
Subject: Re: [PATCH v4 1/2] powerpc/pseries/iommu: Share the per-cpu TCE page
 with the hypervisor.

On Wed, Dec 04, 2019 at 03:26:50PM -0300, Leonardo Bras wrote:
> On Sun, 2019-12-01 at 22:45 -0800, Ram Pai wrote:
> > @@ -206,8 +224,7 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
> >          * from iommu_alloc{,_sg}()
> >          */
> >         if (!tcep) {
> > -               tcep = (__be64 *)__get_free_page(GFP_ATOMIC);
> > -               /* If allocation fails, fall back to the loop implementation */
> > +               tcep = alloc_tce_page();
> >                 if (!tcep) {
> >                         local_irq_restore(flags);
> >                         return tce_build_pSeriesLP(tbl, tcenum, npages, uaddr,
> 
> The comment about failing allocation was removed, but I see no chage of
> behaviour here. 
> 
> Can you please explain what/where it changes? 

You observed it right. The comment should stay put.  Will have it fixed
in my next version.

Thanks,
RP