From: Dave Martin <Dave.Martin@arm.com>
To: Andrew Jones <drjones@redhat.com>
Cc: Okamoto Takayuki <tokamoto@jp.fujitsu.com>,
Christoffer Dall <cdall@kernel.org>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Marc Zyngier <marc.zyngier@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC PATCH 10/16] KVM: arm64: Add a vcpu flag to control SVE visibility for the guest
Date: Wed, 25 Jul 2018 15:41:16 +0100 [thread overview]
Message-ID: <20180725144115.GO4240@e103592.cambridge.arm.com> (raw)
In-Reply-To: <20180725134359.rebcjfsigkvbs2n5@kamzik.brq.redhat.com>
On Wed, Jul 25, 2018 at 03:43:59PM +0200, Andrew Jones wrote:
> On Wed, Jul 25, 2018 at 12:41:06PM +0100, Dave Martin wrote:
[...]
> > The main purpose of system_supports_sve() here is to shadow the check on
> > vcpu_arch->flags with a static branch. If the system doesn't support
> > SVE, we don't pay the runtime cost of the dynamic check on
> > vcpu_arch->flags.
> >
> > If the kernel is built with CONFIG_ARM64_SVE=n, the dynamic check should
> > be entirely optimised away by the compiler.
>
> Ah, that makes sense. Thanks for clarifying it.
>
> >
> > I'd rather not add an explicit comment for this because the same
> > convention is followed elsewhere -- thus for consistency the comment
> > would need to be added in a lot of places.
>
> Agreed that we don't need a comment. A note in the commit message might
> have been nice though.
Sure, I'll add something in the respin.
Cheers
---Dave
WARNING: multiple messages have this Message-ID (diff)
From: Dave.Martin@arm.com (Dave Martin)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH 10/16] KVM: arm64: Add a vcpu flag to control SVE visibility for the guest
Date: Wed, 25 Jul 2018 15:41:16 +0100 [thread overview]
Message-ID: <20180725144115.GO4240@e103592.cambridge.arm.com> (raw)
In-Reply-To: <20180725134359.rebcjfsigkvbs2n5@kamzik.brq.redhat.com>
On Wed, Jul 25, 2018 at 03:43:59PM +0200, Andrew Jones wrote:
> On Wed, Jul 25, 2018 at 12:41:06PM +0100, Dave Martin wrote:
[...]
> > The main purpose of system_supports_sve() here is to shadow the check on
> > vcpu_arch->flags with a static branch. If the system doesn't support
> > SVE, we don't pay the runtime cost of the dynamic check on
> > vcpu_arch->flags.
> >
> > If the kernel is built with CONFIG_ARM64_SVE=n, the dynamic check should
> > be entirely optimised away by the compiler.
>
> Ah, that makes sense. Thanks for clarifying it.
>
> >
> > I'd rather not add an explicit comment for this because the same
> > convention is followed elsewhere -- thus for consistency the comment
> > would need to be added in a lot of places.
>
> Agreed that we don't need a comment. A note in the commit message might
> have been nice though.
Sure, I'll add something in the respin.
Cheers
---Dave
next prev parent reply other threads:[~2018-07-25 14:41 UTC|newest]
Thread overview: 178+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-21 14:57 [RFC PATCH 00/16] KVM: arm64: Initial support for SVE guests Dave Martin
2018-06-21 14:57 ` Dave Martin
2018-06-21 14:57 ` [RFC PATCH 01/16] arm64: fpsimd: Always set TIF_FOREIGN_FPSTATE on task state flush Dave Martin
2018-06-21 14:57 ` Dave Martin
2018-07-06 9:07 ` Alex Bennée
2018-07-06 9:07 ` Alex Bennée
2018-06-21 14:57 ` [RFC PATCH 02/16] KVM: arm64: Delete orphaned declaration for __fpsimd_enabled() Dave Martin
2018-06-21 14:57 ` Dave Martin
2018-07-06 9:08 ` Alex Bennée
2018-07-06 9:08 ` Alex Bennée
2018-06-21 14:57 ` [RFC PATCH 03/16] KVM: arm64: Refactor kvm_arm_num_regs() for easier maintenance Dave Martin
2018-06-21 14:57 ` Dave Martin
2018-07-06 9:20 ` Alex Bennée
2018-07-06 9:20 ` Alex Bennée
2018-06-21 14:57 ` [RFC PATCH 04/16] KVM: arm64: Add missing #include of <linux/bitmap.h> to kvm_host.h Dave Martin
2018-06-21 14:57 ` Dave Martin
2018-07-06 9:21 ` Alex Bennée
2018-07-06 9:21 ` Alex Bennée
2018-06-21 14:57 ` [RFC PATCH 05/16] KVM: arm: Add arch init/uninit hooks Dave Martin
2018-06-21 14:57 ` Dave Martin
2018-07-06 10:02 ` Alex Bennée
2018-07-06 10:02 ` Alex Bennée
2018-07-09 15:15 ` Dave Martin
2018-07-09 15:15 ` Dave Martin
2018-06-21 14:57 ` [RFC PATCH 06/16] arm64/sve: Determine virtualisation-friendly vector lengths Dave Martin
2018-06-21 14:57 ` Dave Martin
2018-07-06 13:20 ` Marc Zyngier
2018-07-06 13:20 ` Marc Zyngier
2018-06-21 14:57 ` [RFC PATCH 07/16] arm64/sve: Enable SVE state tracking for non-task contexts Dave Martin
2018-06-21 14:57 ` Dave Martin
2018-07-25 13:58 ` Alex Bennée
2018-07-25 13:58 ` Alex Bennée
2018-07-25 14:39 ` Dave Martin
2018-07-25 14:39 ` Dave Martin
2018-06-21 14:57 ` [RFC PATCH 08/16] KVM: arm64: Support dynamically hideable system registers Dave Martin
2018-06-21 14:57 ` Dave Martin
2018-07-25 14:12 ` Alex Bennée
2018-07-25 14:12 ` Alex Bennée
2018-07-25 14:36 ` Dave Martin
2018-07-25 14:36 ` Dave Martin
2018-07-25 15:41 ` Alex Bennée
2018-07-25 15:41 ` Alex Bennée
2018-07-26 12:53 ` Dave Martin
2018-07-26 12:53 ` Dave Martin
2018-08-07 19:20 ` Christoffer Dall
2018-08-07 19:20 ` Christoffer Dall
2018-08-08 8:33 ` Dave Martin
2018-08-08 8:33 ` Dave Martin
2018-06-21 14:57 ` [RFC PATCH 09/16] KVM: arm64: Allow ID registers to by dynamically read-as-zero Dave Martin
2018-06-21 14:57 ` Dave Martin
2018-07-25 15:46 ` Alex Bennée
2018-07-25 15:46 ` Alex Bennée
2018-08-06 13:03 ` Christoffer Dall
2018-08-06 13:03 ` Christoffer Dall
2018-08-07 11:09 ` Dave Martin
2018-08-07 11:09 ` Dave Martin
2018-08-07 19:35 ` Christoffer Dall
2018-08-07 19:35 ` Christoffer Dall
2018-08-08 9:11 ` Dave Martin
2018-08-08 9:11 ` Dave Martin
2018-08-08 9:58 ` Christoffer Dall
2018-08-08 9:58 ` Christoffer Dall
2018-08-08 14:03 ` Peter Maydell
2018-08-08 14:03 ` Peter Maydell
2018-08-09 10:19 ` Dave Martin
2018-08-09 10:19 ` Dave Martin
2018-06-21 14:57 ` [RFC PATCH 10/16] KVM: arm64: Add a vcpu flag to control SVE visibility for the guest Dave Martin
2018-06-21 14:57 ` Dave Martin
2018-07-19 11:08 ` Andrew Jones
2018-07-19 11:08 ` Andrew Jones
2018-07-25 11:41 ` Dave Martin
2018-07-25 11:41 ` Dave Martin
2018-07-25 13:43 ` Andrew Jones
2018-07-25 13:43 ` Andrew Jones
2018-07-25 14:41 ` Dave Martin [this message]
2018-07-25 14:41 ` Dave Martin
2018-07-19 15:02 ` Andrew Jones
2018-07-19 15:02 ` Andrew Jones
2018-07-25 11:48 ` Dave Martin
2018-07-25 11:48 ` Dave Martin
2018-06-21 14:57 ` [RFC PATCH 11/16] KVM: arm64/sve: System register context switch and access support Dave Martin
2018-06-21 14:57 ` Dave Martin
2018-07-19 11:11 ` Andrew Jones
2018-07-19 11:11 ` Andrew Jones
2018-07-25 11:45 ` Dave Martin
2018-07-25 11:45 ` Dave Martin
2018-06-21 14:57 ` [RFC PATCH 12/16] KVM: arm64/sve: Context switch the SVE registers Dave Martin
2018-06-21 14:57 ` Dave Martin
2018-07-19 13:13 ` Andrew Jones
2018-07-19 13:13 ` Andrew Jones
2018-07-25 11:50 ` Dave Martin
2018-07-25 11:50 ` Dave Martin
2018-07-25 13:57 ` Andrew Jones
2018-07-25 13:57 ` Andrew Jones
2018-07-25 14:12 ` Dave Martin
2018-07-25 14:12 ` Dave Martin
2018-08-06 13:19 ` Christoffer Dall
2018-08-06 13:19 ` Christoffer Dall
2018-08-07 11:15 ` Dave Martin
2018-08-07 11:15 ` Dave Martin
2018-08-07 19:43 ` Christoffer Dall
2018-08-07 19:43 ` Christoffer Dall
2018-08-08 8:23 ` Dave Martin
2018-08-08 8:23 ` Dave Martin
2018-06-21 14:57 ` [RFC PATCH 13/16] KVM: Allow 2048-bit register access via KVM_{GET, SET}_ONE_REG Dave Martin
2018-06-21 14:57 ` Dave Martin
2018-07-25 15:58 ` Alex Bennée
2018-07-25 15:58 ` Alex Bennée
2018-07-26 12:58 ` Dave Martin
2018-07-26 12:58 ` Dave Martin
2018-07-26 13:55 ` Alex Bennée
2018-07-26 13:55 ` Alex Bennée
2018-07-27 9:26 ` Dave Martin
2018-07-27 9:26 ` Dave Martin
2018-06-21 14:57 ` [RFC PATCH 14/16] KVM: arm64/sve: Add SVE support to register access ioctl interface Dave Martin
2018-06-21 14:57 ` Dave Martin
2018-07-19 13:04 ` Andrew Jones
2018-07-19 13:04 ` Andrew Jones
2018-07-25 14:06 ` Dave Martin
2018-07-25 14:06 ` Dave Martin
2018-07-25 17:20 ` Andrew Jones
2018-07-25 17:20 ` Andrew Jones
2018-07-26 13:10 ` Dave Martin
2018-07-26 13:10 ` Dave Martin
2018-08-03 14:57 ` Dave Martin
2018-08-03 14:57 ` Dave Martin
2018-08-03 15:11 ` Andrew Jones
2018-08-03 15:11 ` Andrew Jones
2018-08-03 15:38 ` Dave Martin
2018-08-03 15:38 ` Dave Martin
2018-08-06 13:25 ` Christoffer Dall
2018-08-06 13:25 ` Christoffer Dall
2018-08-07 11:17 ` Dave Martin
2018-08-07 11:17 ` Dave Martin
2018-06-21 14:57 ` [RFC PATCH 15/16] KVM: arm64: Enumerate SVE register indices for KVM_GET_REG_LIST Dave Martin
2018-06-21 14:57 ` Dave Martin
2018-07-19 14:12 ` Andrew Jones
2018-07-19 14:12 ` Andrew Jones
2018-07-25 14:50 ` Dave Martin
2018-07-25 14:50 ` Dave Martin
2018-06-21 14:57 ` [RFC PATCH 16/16] KVM: arm64/sve: Report and enable SVE API extensions for userspace Dave Martin
2018-06-21 14:57 ` Dave Martin
2018-07-19 14:59 ` Andrew Jones
2018-07-19 14:59 ` Andrew Jones
2018-07-25 15:27 ` Dave Martin
2018-07-25 15:27 ` Dave Martin
2018-07-25 16:52 ` Andrew Jones
2018-07-25 16:52 ` Andrew Jones
2018-07-26 13:18 ` Dave Martin
2018-07-26 13:18 ` Dave Martin
2018-08-06 13:41 ` Christoffer Dall
2018-08-06 13:41 ` Christoffer Dall
2018-08-07 11:23 ` Dave Martin
2018-08-07 11:23 ` Dave Martin
2018-08-07 20:08 ` Christoffer Dall
2018-08-07 20:08 ` Christoffer Dall
2018-08-08 8:30 ` Dave Martin
2018-08-08 8:30 ` Dave Martin
2018-07-19 15:24 ` Andrew Jones
2018-07-19 15:24 ` Andrew Jones
2018-07-26 13:23 ` Dave Martin
2018-07-26 13:23 ` Dave Martin
2018-07-06 8:22 ` [RFC PATCH 00/16] KVM: arm64: Initial support for SVE guests Alex Bennée
2018-07-06 8:22 ` Alex Bennée
2018-07-06 9:05 ` Dave Martin
2018-07-06 9:05 ` Dave Martin
2018-07-06 9:20 ` Alex Bennée
2018-07-06 9:20 ` Alex Bennée
2018-07-06 9:23 ` Peter Maydell
2018-07-06 9:23 ` Peter Maydell
2018-07-06 10:11 ` Alex Bennée
2018-07-06 10:11 ` Alex Bennée
2018-07-06 10:14 ` Peter Maydell
2018-07-06 10:14 ` Peter Maydell
2018-08-06 13:05 ` Christoffer Dall
2018-08-06 13:05 ` Christoffer Dall
2018-08-07 11:18 ` Dave Martin
2018-08-07 11:18 ` Dave Martin
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