From: Marc Zyngier <marc.zyngier@arm.com>
To: Pavel Fedin <p.fedin@samsung.com>,
kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: christoffer.dall@linaro.org
Subject: Re: [PATCH 0/3] KVM: arm64: BUG FIX: Correctly handle zero register transfers
Date: Thu, 03 Dec 2015 10:05:59 +0000 [thread overview]
Message-ID: <56601407.7020407@arm.com> (raw)
In-Reply-To: <cover.1449136209.git.p.fedin@samsung.com>
On 03/12/15 09:58, Pavel Fedin wrote:
> ARM64 CPU has zero register which is read-only, with a value of 0.
> However, KVM currently incorrectly recognizes it being SP (because
> Rt == 31, and in struct user_pt_regs 'regs' array is followed by SP),
> resulting in invalid value being read, or even SP corruption on write.
No really. XZR and SP do share the same encoding.
> The problem has been discovered by performing an operation
>
> *((volatile int *)reg) = 0;
>
> which compiles as "str xzr, [xx]", and resulted in strange values being
> written.
Interesting find. Which compiler is that?
Thanks,
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2015-12-03 10:06 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-03 9:58 [PATCH 0/3] KVM: arm64: BUG FIX: Correctly handle zero register transfers Pavel Fedin
2015-12-03 9:58 ` [PATCH 1/3] KVM: arm64: Correctly handle zero register during MMIO Pavel Fedin
2015-12-03 10:51 ` Marc Zyngier
2015-12-03 9:58 ` [PATCH 2/3] KVM: arm64: Correctly handle zero register in system register accesses Pavel Fedin
2015-12-03 10:49 ` Marc Zyngier
2015-12-03 11:08 ` Pavel Fedin
2015-12-03 11:36 ` Marc Zyngier
2015-12-03 11:55 ` Pavel Fedin
2015-12-03 13:12 ` Marc Zyngier
2015-12-03 9:58 ` [PATCH 3/3] KVM: arm64: Get rid of old vcpu_reg() Pavel Fedin
2015-12-03 10:05 ` Marc Zyngier [this message]
2015-12-03 10:53 ` [PATCH 0/3] KVM: arm64: BUG FIX: Correctly handle zero register transfers Pavel Fedin
2015-12-03 11:39 ` Marc Zyngier
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