From: Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>
To: Oleksandr Tyshchenko <olekstysh-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Oleksandr Tyshchenko
<oleksandr_tyshchenko-uRwfk40T5oI@public.gmane.org>,
Volodymyr Babchuk
<vlad.babchuk-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
Andrii Anisov
<andrii.anisov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Oleksandr Andrushchenko
<andr2000-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
al1img <al1img-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
Artem Mygaiev <joculator-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: Re: [RFC PATCH v1] iommu/io-pgtable-arm-v7s: Check for leaf entry right after finding it
Date: Fri, 24 Feb 2017 15:18:23 +0000 [thread overview]
Message-ID: <20170224151823.GH20130@arm.com> (raw)
In-Reply-To: <CAPD2p-nPoiSanU4jYvnaYtAbbERE8c=4mLjTC3NX2bGYkZM5UA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
On Tue, Feb 21, 2017 at 03:31:26PM +0200, Oleksandr Tyshchenko wrote:
> On Tue, Feb 21, 2017 at 2:00 PM, Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org> wrote:
> > Would it not be more logical (and simpler) to just check that the thing
> > we dereference is valid to dereference when we dereference it? i.e.:
> >
> > -----8<-----
> > diff --git a/drivers/iommu/io-pgtable-arm-v7s.c
> > b/drivers/iommu/io-pgtable-arm-v7s.c
> > index 0769276c0537..f3112f9ff494 100644
> > --- a/drivers/iommu/io-pgtable-arm-v7s.c
> > +++ b/drivers/iommu/io-pgtable-arm-v7s.c
> > @@ -418,8 +418,10 @@ static int __arm_v7s_map(struct arm_v7s_io_pgtable
> > *data, unsigned long iova,
> > pte |= ARM_V7S_ATTR_NS_TABLE;
> >
> > __arm_v7s_set_pte(ptep, pte, 1, cfg);
> > - } else {
> > + } else if (ARM_V7S_PTE_IS_TABLE(pte, lvl)) {
> > cptep = iopte_deref(pte, lvl);
> > + } else {
> > + return -EEXIST;
> > }
> >
> > /* Rinse, repeat */
> > ----->8-----
>
> Agree. Sounds reasonable.
>
> >
> > I think the equivalent could be done in LPAE as well.
>
> OK.
>
> I will resend both modified patches without RFC prefix, right?
Sounds good to me.
Will
WARNING: multiple messages have this Message-ID (diff)
From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH v1] iommu/io-pgtable-arm-v7s: Check for leaf entry right after finding it
Date: Fri, 24 Feb 2017 15:18:23 +0000 [thread overview]
Message-ID: <20170224151823.GH20130@arm.com> (raw)
In-Reply-To: <CAPD2p-nPoiSanU4jYvnaYtAbbERE8c=4mLjTC3NX2bGYkZM5UA@mail.gmail.com>
On Tue, Feb 21, 2017 at 03:31:26PM +0200, Oleksandr Tyshchenko wrote:
> On Tue, Feb 21, 2017 at 2:00 PM, Robin Murphy <robin.murphy@arm.com> wrote:
> > Would it not be more logical (and simpler) to just check that the thing
> > we dereference is valid to dereference when we dereference it? i.e.:
> >
> > -----8<-----
> > diff --git a/drivers/iommu/io-pgtable-arm-v7s.c
> > b/drivers/iommu/io-pgtable-arm-v7s.c
> > index 0769276c0537..f3112f9ff494 100644
> > --- a/drivers/iommu/io-pgtable-arm-v7s.c
> > +++ b/drivers/iommu/io-pgtable-arm-v7s.c
> > @@ -418,8 +418,10 @@ static int __arm_v7s_map(struct arm_v7s_io_pgtable
> > *data, unsigned long iova,
> > pte |= ARM_V7S_ATTR_NS_TABLE;
> >
> > __arm_v7s_set_pte(ptep, pte, 1, cfg);
> > - } else {
> > + } else if (ARM_V7S_PTE_IS_TABLE(pte, lvl)) {
> > cptep = iopte_deref(pte, lvl);
> > + } else {
> > + return -EEXIST;
> > }
> >
> > /* Rinse, repeat */
> > ----->8-----
>
> Agree. Sounds reasonable.
>
> >
> > I think the equivalent could be done in LPAE as well.
>
> OK.
>
> I will resend both modified patches without RFC prefix, right?
Sounds good to me.
Will
next prev parent reply other threads:[~2017-02-24 15:18 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-16 13:52 [RFC PATCH v1] iommu/io-pgtable-arm-v7s: Check for leaf entry right after finding it Oleksandr Tyshchenko
2017-02-16 13:52 ` Oleksandr Tyshchenko
[not found] ` <1487253137-13792-1-git-send-email-olekstysh-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-02-16 13:58 ` Oleksandr Tyshchenko
2017-02-16 13:58 ` Oleksandr Tyshchenko
2017-02-21 12:00 ` Robin Murphy
2017-02-21 12:00 ` Robin Murphy
[not found] ` <bc24299c-748a-4b86-fead-a9ed6b5e5b9f-5wv7dgnIgG8@public.gmane.org>
2017-02-21 13:31 ` Oleksandr Tyshchenko
2017-02-21 13:31 ` Oleksandr Tyshchenko
[not found] ` <CAPD2p-nPoiSanU4jYvnaYtAbbERE8c=4mLjTC3NX2bGYkZM5UA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-02-24 15:18 ` Will Deacon [this message]
2017-02-24 15:18 ` Will Deacon
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