From: Oliver Upton <oliver.upton@linux.dev>
To: Sebastian Ene <sebastianene@google.com>
Cc: catalin.marinas@arm.com, james.morse@arm.com,
jean-philippe@linaro.org, maz@kernel.org, qperret@google.com,
qwandor@google.com, suzuki.poulose@arm.com, tabba@google.com,
will@kernel.org, yuzenghui@huawei.com, kvmarm@lists.linux.dev,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, kernel-team@android.com
Subject: Re: [PATCH 2/2] KVM: arm64: Allow only the specified FF-A calls to be forwarded to TZ
Date: Tue, 26 Mar 2024 01:42:26 -0700 [thread overview]
Message-ID: <ZgKKcurtndJaIwAV@linux.dev> (raw)
In-Reply-To: <ZgFgI0Ky2m4MUbw-@google.com>
On Mon, Mar 25, 2024 at 11:29:39AM +0000, Sebastian Ene wrote:
> On Fri, Mar 22, 2024 at 07:07:52PM -0700, Oliver Upton wrote:
> > On Fri, Mar 22, 2024 at 12:43:03PM +0000, Sebastian Ene wrote:
> > > The previous logic used a deny list to filter the FF-A calls. Because of
> > > this, some of the calls escaped the check and they were forwarded by
> > > default to Trustzone. (eg. FFA_MSG_SEND_DIRECT_REQ was denied but the 64
> > > bit version of the call was not).
> > > Modify the logic to use an allowlist and allow only the calls specified in
> > > the filter function to be proxied to TZ from the hypervisor.
>
> Hi Oliver,
>
> >
> > I had discussed this with Will back when the feature was upstreamed and
> > he said there's a lot of off-label calls that necessitate a denylist
> > implementation. Has anything changed to give us confidence that we can
> > be restrictive, at least on the FF-A range?
> >
>
> I remember your proposal for having an allowlist instead. The current change makes
> sense if we have https://lore.kernel.org/kvmarm/20240322124303.309423-1-sebastianene@google.com/
> which opens the window for more FF-A calls to be forwarded to TZ.
Got it. Last time I didn't catch the level of abuse we expect to endure
from vendors, but now it seems we will not support non-conforming calls
that appear in standardized SMC ranges.
Adding mention of this to the changelog might be a good idea then.
--
Thanks,
Oliver
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2024-03-26 8:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-22 12:43 [PATCH 1/2] KVM: arm64: Fix the identification range for the FF-A smcs Sebastian Ene
2024-03-22 12:43 ` [PATCH 2/2] KVM: arm64: Allow only the specified FF-A calls to be forwarded to TZ Sebastian Ene
2024-03-23 2:07 ` Oliver Upton
2024-03-25 11:29 ` Sebastian Ene
2024-03-26 8:42 ` Oliver Upton [this message]
2024-03-28 13:59 ` Sebastian Ene
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=ZgKKcurtndJaIwAV@linux.dev \
--to=oliver.upton@linux.dev \
--cc=catalin.marinas@arm.com \
--cc=james.morse@arm.com \
--cc=jean-philippe@linaro.org \
--cc=kernel-team@android.com \
--cc=kvmarm@lists.linux.dev \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=maz@kernel.org \
--cc=qperret@google.com \
--cc=qwandor@google.com \
--cc=sebastianene@google.com \
--cc=suzuki.poulose@arm.com \
--cc=tabba@google.com \
--cc=will@kernel.org \
--cc=yuzenghui@huawei.com \
/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).