From: Will Deacon <will@kernel.org>
To: Florian Fainelli <f.fainelli@gmail.com>
Cc: "open list:KERNEL VIRTUAL MACHINE (KVM)" <kvm@vger.kernel.org>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Marc Zyngier" <marc.zyngier@arm.com>,
"Catalin Marinas" <catalin.marinas@arm.com>,
"Will Deacon" <will.deacon@arm.com>,
"open list" <linux-kernel@vger.kernel.org>,
stable@vger.kernel.org,
"Christoffer Dall" <christoffer.dall@linaro.org>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"open list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)"
<kvmarm@lists.cs.columbia.edu>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH stable 4.9] arm64: entry: Place an SB sequence following an ERET instruction
Date: Wed, 24 Jun 2020 13:58:46 +0100 [thread overview]
Message-ID: <20200624125846.GD6270@willie-the-truck> (raw)
In-Reply-To: <2bcebe48-1218-403a-798c-da30d678fdd6@gmail.com>
On Tue, Jun 23, 2020 at 11:46:37AM -0700, Florian Fainelli wrote:
> On 6/11/20 9:42 PM, Florian Fainelli wrote:
> > From: Will Deacon <will.deacon@arm.com>
> >
> > commit 679db70801da9fda91d26caf13bf5b5ccc74e8e8 upstream
> >
> > Some CPUs can speculate past an ERET instruction and potentially perform
> > speculative accesses to memory before processing the exception return.
> > Since the register state is often controlled by a lower privilege level
> > at the point of an ERET, this could potentially be used as part of a
> > side-channel attack.
> >
> > This patch emits an SB sequence after each ERET so that speculation is
> > held up on exception return.
> >
> > Signed-off-by: Will Deacon <will.deacon@arm.com>
> > [florian: Adjust hyp-entry.S to account for the label]
> > Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
> > ---
> > Will,
> >
> > Can you confirm that for 4.9 these are the only places that require
> > patching? Thank you!
>
> Hi Will, Catalin,
>
> Does this look good to you for a 4.9 backport? I would like to see this
> included at some point since this pertains to CVE-2020-13844.
I think you're missing one of the ERET instructions in hyp/entry.S
Will
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prev parent reply other threads:[~2020-06-24 12:58 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-12 4:42 [PATCH stable 4.9] arm64: entry: Place an SB sequence following an ERET instruction Florian Fainelli
2020-06-23 18:46 ` Florian Fainelli
2020-06-24 12:58 ` Will Deacon [this message]
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