From: Mark Brown <broonie@kernel.org>
To: Marc Zyngier <maz@kernel.org>
Cc: kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org,
dave.martin@arm.com, daniel.kiss@arm.com,
Will Deacon <will@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
James Morse <james.morse@arm.com>,
Julien Thierry <julien.thierry.kdev@gmail.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
ascull@google.com, qperret@google.com, kernel-team@android.com
Subject: Re: [PATCH v2 05/11] arm64: sve: Provide a conditional update accessor for ZCR_ELx
Date: Fri, 19 Mar 2021 16:42:36 +0000 [thread overview]
Message-ID: <20210319164236.GH5619@sirena.org.uk> (raw)
In-Reply-To: <20210318122532.505263-6-maz@kernel.org>
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On Thu, Mar 18, 2021 at 12:25:26PM +0000, Marc Zyngier wrote:
> A common pattern is to conditionally update ZCR_ELx in order
> to avoid the "self-synchronizing" effect that writing to this
> register has.
>
> Let's provide an accessor that does exactly this.
Reviewed-by: Mark Brown <broonie@kernel.org>
> +#define sve_cond_update_zcr_vq(val, reg) \
> + do { \
> + u64 __zcr = read_sysreg_s((reg)); \
> + u64 __new = __zcr & ~ZCR_ELx_LEN_MASK; \
> + __new |= (val) & ZCR_ELx_LEN_MASK; \
> + if (__zcr != __new) \
> + write_sysreg_s(__new, (reg)); \
> + } while (0)
> +
Do compilers actually do much better with this than with a static
inline like the other functions in this header? Seems like something
they should be figuring out.
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next prev parent reply other threads:[~2021-03-19 16:44 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-18 12:25 [PATCH v2 00/11] KVM: arm64: Enable SVE support on nVHE systems Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 01/11] KVM: arm64: Provide KVM's own save/restore SVE primitives Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 02/11] KVM: arm64: Use {read, write}_sysreg_el1 to access ZCR_EL1 Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 03/11] KVM: arm64: Let vcpu_sve_pffr() handle HYP VAs Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 04/11] KVM: arm64: Introduce vcpu_sve_vq() helper Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 05/11] arm64: sve: Provide a conditional update accessor for ZCR_ELx Marc Zyngier
2021-03-18 13:32 ` Will Deacon
2021-03-19 16:42 ` Mark Brown [this message]
2021-03-19 16:51 ` Marc Zyngier
2021-03-19 16:58 ` Mark Brown
2021-03-18 12:25 ` [PATCH v2 06/11] KVM: arm64: Rework SVE host-save/guest-restore Marc Zyngier
2021-03-18 13:34 ` Will Deacon
2021-03-18 12:25 ` [PATCH v2 07/11] KVM: arm64: Map SVE context at EL2 when available Marc Zyngier
2021-03-18 13:35 ` Will Deacon
2021-03-18 12:25 ` [PATCH v2 08/11] KVM: arm64: Save guest's ZCR_EL1 before saving the FPSIMD state Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 09/11] KVM: arm64: Trap host SVE accesses when the FPSIMD state is dirty Marc Zyngier
2021-03-18 14:11 ` Will Deacon
2021-03-18 14:29 ` Marc Zyngier
2021-03-18 18:40 ` Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 10/11] KVM: arm64: Save/restore SVE state for nVHE Marc Zyngier
2021-03-18 14:13 ` Will Deacon
2021-03-18 14:32 ` Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 11/11] KVM: arm64: Enable SVE support " Marc Zyngier
2021-03-19 17:53 ` [PATCH v2 00/11] KVM: arm64: Enable SVE support on nVHE systems Mark Brown
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