From: Marc Zyngier <maz@kernel.org>
To: Quentin Perret <qperret@google.com>
Cc: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org,
James Morse <james.morse@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Alexandru Elisei <alexandru.elisei@arm.com>,
Will Deacon <will@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
kernel-team@android.com, stable@vger.kernel.org
Subject: Re: [PATCH v2 1/2] arm64: Move .hyp.rodata outside of the _sdata.._edata range
Date: Mon, 02 Aug 2021 14:20:42 +0100 [thread overview]
Message-ID: <87mtq00yqd.wl-maz@kernel.org> (raw)
In-Reply-To: <YQfu6+3uo6qlxrpv@google.com>
Hi Quentin,
On Mon, 02 Aug 2021 14:11:07 +0100,
Quentin Perret <qperret@google.com> wrote:
>
> Hi Marc,
>
> On Monday 02 Aug 2021 at 13:38:29 (+0100), Marc Zyngier wrote:
> > The HYP rodata section is currently lumped together with the BSS,
> > which isn't exactly what is expected (it gets registered with
> > kmemleak, for example).
> >
> > Move it away so that it is actually marked RO. As an added
> > benefit, it isn't registered with kmemleak anymore.
>
> 2d7bf218ca73 ("KVM: arm64: Add .hyp.data..ro_after_init ELF section")
> states explicitly that the hyp ro_after_init section should remain RW in
> the host as it is expected to modify it before initializing EL2. But I
> can't seem to trigger anything with this patch applied, so I'll look
> into this a bit more.
The switch to RO happens quite late. And if the host was to actually
try and change things there, it would be screwed anyway (we will have
already removed the pages from its S2).
I wouldn't be surprised if this was a consequence of the way we now
build the HYP object, and the comment in the original commit may not
be valid anymore.
>
> > Fixes: 380e18ade4a5 ("KVM: arm64: Introduce a BSS section for use at Hyp")
>
> Not sure this is the patch to blame?
My bad, this is plain wrong. I'm not sure it can be applied earlier
though if my rambling above is correct.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <maz@kernel.org>
To: Quentin Perret <qperret@google.com>
Cc: kernel-team@android.com, kvm@vger.kernel.org,
Will Deacon <will@kernel.org>,
stable@vger.kernel.org, Catalin Marinas <catalin.marinas@arm.com>,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 1/2] arm64: Move .hyp.rodata outside of the _sdata.._edata range
Date: Mon, 02 Aug 2021 14:20:42 +0100 [thread overview]
Message-ID: <87mtq00yqd.wl-maz@kernel.org> (raw)
In-Reply-To: <YQfu6+3uo6qlxrpv@google.com>
Hi Quentin,
On Mon, 02 Aug 2021 14:11:07 +0100,
Quentin Perret <qperret@google.com> wrote:
>
> Hi Marc,
>
> On Monday 02 Aug 2021 at 13:38:29 (+0100), Marc Zyngier wrote:
> > The HYP rodata section is currently lumped together with the BSS,
> > which isn't exactly what is expected (it gets registered with
> > kmemleak, for example).
> >
> > Move it away so that it is actually marked RO. As an added
> > benefit, it isn't registered with kmemleak anymore.
>
> 2d7bf218ca73 ("KVM: arm64: Add .hyp.data..ro_after_init ELF section")
> states explicitly that the hyp ro_after_init section should remain RW in
> the host as it is expected to modify it before initializing EL2. But I
> can't seem to trigger anything with this patch applied, so I'll look
> into this a bit more.
The switch to RO happens quite late. And if the host was to actually
try and change things there, it would be screwed anyway (we will have
already removed the pages from its S2).
I wouldn't be surprised if this was a consequence of the way we now
build the HYP object, and the comment in the original commit may not
be valid anymore.
>
> > Fixes: 380e18ade4a5 ("KVM: arm64: Introduce a BSS section for use at Hyp")
>
> Not sure this is the patch to blame?
My bad, this is plain wrong. I'm not sure it can be applied earlier
though if my rambling above is correct.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <maz@kernel.org>
To: Quentin Perret <qperret@google.com>
Cc: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org,
James Morse <james.morse@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Alexandru Elisei <alexandru.elisei@arm.com>,
Will Deacon <will@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
kernel-team@android.com, stable@vger.kernel.org
Subject: Re: [PATCH v2 1/2] arm64: Move .hyp.rodata outside of the _sdata.._edata range
Date: Mon, 02 Aug 2021 14:20:42 +0100 [thread overview]
Message-ID: <87mtq00yqd.wl-maz@kernel.org> (raw)
In-Reply-To: <YQfu6+3uo6qlxrpv@google.com>
Hi Quentin,
On Mon, 02 Aug 2021 14:11:07 +0100,
Quentin Perret <qperret@google.com> wrote:
>
> Hi Marc,
>
> On Monday 02 Aug 2021 at 13:38:29 (+0100), Marc Zyngier wrote:
> > The HYP rodata section is currently lumped together with the BSS,
> > which isn't exactly what is expected (it gets registered with
> > kmemleak, for example).
> >
> > Move it away so that it is actually marked RO. As an added
> > benefit, it isn't registered with kmemleak anymore.
>
> 2d7bf218ca73 ("KVM: arm64: Add .hyp.data..ro_after_init ELF section")
> states explicitly that the hyp ro_after_init section should remain RW in
> the host as it is expected to modify it before initializing EL2. But I
> can't seem to trigger anything with this patch applied, so I'll look
> into this a bit more.
The switch to RO happens quite late. And if the host was to actually
try and change things there, it would be screwed anyway (we will have
already removed the pages from its S2).
I wouldn't be surprised if this was a consequence of the way we now
build the HYP object, and the comment in the original commit may not
be valid anymore.
>
> > Fixes: 380e18ade4a5 ("KVM: arm64: Introduce a BSS section for use at Hyp")
>
> Not sure this is the patch to blame?
My bad, this is plain wrong. I'm not sure it can be applied earlier
though if my rambling above is correct.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
_______________________________________________
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:[~2021-08-02 13:20 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-02 12:38 [PATCH v2 0/2] KVM: arm64: Prevent kmemleak from accessing HYP data Marc Zyngier
2021-08-02 12:38 ` Marc Zyngier
2021-08-02 12:38 ` Marc Zyngier
2021-08-02 12:38 ` [PATCH v2 1/2] arm64: Move .hyp.rodata outside of the _sdata.._edata range Marc Zyngier
2021-08-02 12:38 ` Marc Zyngier
2021-08-02 12:38 ` Marc Zyngier
2021-08-02 13:11 ` Quentin Perret
2021-08-02 13:11 ` Quentin Perret
2021-08-02 13:11 ` Quentin Perret
2021-08-02 13:20 ` Marc Zyngier [this message]
2021-08-02 13:20 ` Marc Zyngier
2021-08-02 13:20 ` Marc Zyngier
2021-08-02 13:47 ` Quentin Perret
2021-08-02 13:47 ` Quentin Perret
2021-08-02 13:47 ` Quentin Perret
2021-08-02 16:52 ` Catalin Marinas
2021-08-02 16:52 ` Catalin Marinas
2021-08-02 16:52 ` Catalin Marinas
2021-08-02 12:38 ` [PATCH v2 2/2] KVM: arm64: Unregister HYP sections from kmemleak in protected mode Marc Zyngier
2021-08-02 12:38 ` Marc Zyngier
2021-08-02 12:38 ` Marc Zyngier
2021-08-02 16:52 ` Catalin Marinas
2021-08-02 16:52 ` Catalin Marinas
2021-08-02 16:52 ` Catalin Marinas
2021-08-04 12:26 ` [PATCH v2 0/2] KVM: arm64: Prevent kmemleak from accessing HYP data Marc Zyngier
2021-08-04 12:26 ` Marc Zyngier
2021-08-04 12:26 ` Marc Zyngier
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=87mtq00yqd.wl-maz@kernel.org \
--to=maz@kernel.org \
--cc=alexandru.elisei@arm.com \
--cc=catalin.marinas@arm.com \
--cc=james.morse@arm.com \
--cc=kernel-team@android.com \
--cc=kvm@vger.kernel.org \
--cc=kvmarm@lists.cs.columbia.edu \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=qperret@google.com \
--cc=stable@vger.kernel.org \
--cc=suzuki.poulose@arm.com \
--cc=will@kernel.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.