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From: Hanjun Guo <guohanjun@huawei.com>
To: Marc Zyngier <marc.zyngier@arm.com>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	kvmarm <kvmarm@lists.cs.columbia.edu>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Peter Maydell <peter.maydell@linaro.org>,
	Christoffer Dall <christoffer.dall@linaro.org>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	"Robin Murphy" <robin.murphy@arm.com>,
	Jon Masters <jcm@redhat.com>
Subject: Re: [PATCH v2 16/16] arm64: Add ARM_SMCCC_ARCH_WORKAROUND_1 BP hardening support
Date: Fri, 2 Feb 2018 11:43:49 +0800	[thread overview]
Message-ID: <7e62d00e-df3b-1fb8-8e5e-83e1cf0e86bf@huawei.com> (raw)
In-Reply-To: <8183e28a-39e7-e4f0-d704-35a0beb14ef0@arm.com>

On 2018/2/1 16:53, Marc Zyngier wrote:
[...]
>>>> ... and actually, perhaps it makes sense for the
>>>> SMCCC_ARCH_WORKAROUND_1 check to be completely independent of MIDR
>>>> based errata matching?
>>>>
>>>> I.e., if SMCCC v1.1 and SMCCC_ARCH_WORKAROUND_1 are both implemented,
>>>> we should probably invoke it even if the MIDR is not known to belong
>>>> to an affected implementation.
>>>
>>> This would have an impact on big-little systems, for which there is
>>> often a bunch of unaffected CPUs.
>>
>> I think it's what we are doing now, SMCCC v1.1 didn't provide the ability
>> to report per-cpu SMCCC_ARCH_WORKAROUND_1, and it said:
>>  - The discovery call must return the same result on all PEs in the system.
>>  - In heterogeneous systems with some PEs that require mitigation and others
>>    that do not, the firmware must provide a safe implementation of this
>>    function on all PEs.
>>
>> So from the spec that it's the firmware to take care of unaffected CPUs,
>> to the kernel it's the same.
> 
> The spec makes it safe. The MIDR list makes it fast.

Got it, thank you for clarifying this.

Thanks
Hanjun

  reply	other threads:[~2018-02-02  3:45 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-29 17:45 [PATCH v2 00/16] arm64: Add SMCCC v1.1 support and CVE-2017-5715 (Spectre variant 2) mitigation Marc Zyngier
2018-01-29 17:45 ` [PATCH v2 01/16] arm64: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls Marc Zyngier
2018-01-29 17:45 ` [PATCH v2 02/16] arm: " Marc Zyngier
2018-01-29 17:45 ` [PATCH v2 03/16] arm/arm64: KVM: Consolidate the PSCI include files Marc Zyngier
2018-01-29 17:45 ` [PATCH v2 04/16] arm/arm64: KVM: Add PSCI_VERSION helper Marc Zyngier
2018-01-30 13:15   ` Robin Murphy
2018-01-30 14:52     ` Marc Zyngier
2018-01-29 17:45 ` [PATCH v2 05/16] arm/arm64: KVM: Add smccc accessors to PSCI code Marc Zyngier
2018-01-29 17:45 ` [PATCH v2 06/16] arm/arm64: KVM: Implement PSCI 1.0 support Marc Zyngier
2018-01-29 17:45 ` [PATCH v2 07/16] arm/arm64: KVM: Add PSCI version selection API Marc Zyngier
2018-01-31 17:38   ` Andrew Jones
2018-01-31 17:45     ` Marc Zyngier
2018-01-31 18:03       ` Andrew Jones
2018-01-31 18:36         ` Marc Zyngier
2018-01-31 19:15           ` Andrew Jones
2018-01-31 18:11   ` kbuild test robot
2018-01-29 17:45 ` [PATCH v2 08/16] arm/arm64: KVM: Advertise SMCCC v1.1 Marc Zyngier
2018-01-30  0:23   ` Russell King - ARM Linux
2018-01-30 12:28     ` Marc Zyngier
2018-01-29 17:45 ` [PATCH v2 09/16] arm/arm64: KVM: Turn kvm_psci_version into a static inline Marc Zyngier
2018-01-29 17:45 ` [PATCH v2 10/16] arm64: KVM: Report SMCCC_ARCH_WORKAROUND_1 BP hardening support Marc Zyngier
2018-01-30 12:38   ` Robin Murphy
2018-01-29 17:45 ` [PATCH v2 11/16] arm64: KVM: Add SMCCC_ARCH_WORKAROUND_1 fast handling Marc Zyngier
2018-01-29 17:45 ` [PATCH v2 12/16] firmware/psci: Expose PSCI conduit Marc Zyngier
2018-01-29 17:55   ` Lorenzo Pieralisi
2018-01-29 17:45 ` [PATCH v2 13/16] firmware/psci: Expose SMCCC version through psci_ops Marc Zyngier
2018-01-29 18:39   ` Lorenzo Pieralisi
2018-01-30 12:09     ` Marc Zyngier
2018-01-30 12:55   ` Robin Murphy
2018-01-30 13:51     ` Marc Zyngier
2018-01-29 17:45 ` [PATCH v2 14/16] arm/arm64: smccc: Make function identifiers an unsigned quantity Marc Zyngier
2018-01-29 17:45 ` [PATCH v2 15/16] arm/arm64: smccc: Implement SMCCC v1.1 inline primitive Marc Zyngier
2018-01-29 19:07   ` Robin Murphy
2018-01-30  8:54     ` Marc Zyngier
2018-01-29 21:45   ` Ard Biesheuvel
2018-01-30 12:27     ` Marc Zyngier
2018-01-30 12:29       ` Ard Biesheuvel
2018-01-29 17:45 ` [PATCH v2 16/16] arm64: Add ARM_SMCCC_ARCH_WORKAROUND_1 BP hardening support Marc Zyngier
2018-01-29 19:41   ` Ard Biesheuvel
2018-01-30 12:10     ` Marc Zyngier
2018-01-31 13:56   ` Hanjun Guo
2018-01-31 14:11     ` Marc Zyngier
2018-01-31 14:35       ` Ard Biesheuvel
2018-01-31 14:38         ` Ard Biesheuvel
2018-01-31 15:05           ` Marc Zyngier
2018-02-01  2:40             ` Hanjun Guo
2018-02-01  6:52               ` Hanjun Guo
2018-02-01  8:53               ` Marc Zyngier
2018-02-02  3:43                 ` Hanjun Guo [this message]
2018-06-09 13:22 ` [PATCH v2 00/16] arm64: Add SMCCC v1.1 support and CVE-2017-5715 (Spectre variant 2) mitigation Jon Masters
2018-06-09 14:06   ` Marc Zyngier

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