From: Zenghui Yu <yuzenghui@huawei.com>
To: Marc Zyngier <maz@kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<kvmarm@lists.cs.columbia.edu>, <kvm@vger.kernel.org>,
<linux-kernel@vger.kernel.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Jason Cooper <jason@lakedaemon.net>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Eric Auger <eric.auger@redhat.com>,
Robert Richter <rrichter@marvell.com>,
James Morse <james.morse@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Julien Thierry <julien.thierry.kdev@gmail.com>
Subject: Re: [PATCH v4 02/20] irqchip/gic-v3: Use SGIs without active state if offered
Date: Mon, 17 Feb 2020 17:18:10 +0800 [thread overview]
Message-ID: <d8dc634f-bdd6-b2e6-a398-02b7e04efe67@huawei.com> (raw)
In-Reply-To: <20200214145736.18550-3-maz@kernel.org>
Hi Marc,
On 2020/2/14 22:57, Marc Zyngier wrote:
> To allow the direct injection of SGIs into a guest, the GICv4.1
> architecture has to sacrifice the Active state so that SGIs look
> a lot like LPIs (they are injected by the same mechanism).
>
> In order not to break existing software, the architecture gives
> offers guests OSs the choice: SGIs with or without an active
> state. It is the hypervisors duty to honor the guest's choice.
>
> For this, the architecture offers a discovery bit indicating whether
> the GIC supports GICv4.1 SGIs (GICD_TYPER2.nASSGIcap), and another
> bit indicating whether the guest wants Active-less SGIs or not
> (controlled by GICD_CTLR.nASSGIreq).
>
> A hypervisor not supporting GICv4.1 SGIs would leave nASSGIcap
> clear, and a guest not knowing about GICv4.1 SGIs (or definitely
> wanting an Active state) would leave nASSGIreq clear (both being
> thankfully backward compatible with oler revisions of the GIC).
older?
>
> Since Linux is perfectly happy without an active state on SGIs,
> inform the hypervisor that we'll use that if offered.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
Per the description of these two bits in the commit message,
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Thanks
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next prev parent reply other threads:[~2020-02-17 9:18 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-14 14:57 [PATCH v4 00/20] irqchip/gic-v4: GICv4.1 architecture support Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 01/20] irqchip/gic-v4.1: Skip absent CPUs while iterating over redistributors Marc Zyngier
2020-02-17 9:11 ` Zenghui Yu
2020-02-14 14:57 ` [PATCH v4 02/20] irqchip/gic-v3: Use SGIs without active state if offered Marc Zyngier
2020-02-17 9:18 ` Zenghui Yu [this message]
2020-02-14 14:57 ` [PATCH v4 03/20] irqchip/gic-v4.1: Advertise support v4.1 to KVM Marc Zyngier
2020-02-17 9:09 ` Zenghui Yu
2020-02-14 14:57 ` [PATCH v4 04/20] irqchip/gic-v4.1: Map the ITS SGIR register page Marc Zyngier
2020-02-20 3:17 ` Zenghui Yu
2020-02-14 14:57 ` [PATCH v4 05/20] irqchip/gic-v4.1: Plumb skeletal VSGI irqchip Marc Zyngier
2020-02-20 3:21 ` Zenghui Yu
2020-02-14 14:57 ` [PATCH v4 06/20] irqchip/gic-v4.1: Add initial SGI configuration Marc Zyngier
2020-02-18 7:25 ` Zenghui Yu
2020-02-18 9:46 ` Marc Zyngier
2020-02-20 3:25 ` Zenghui Yu
2020-02-14 14:57 ` [PATCH v4 07/20] irqchip/gic-v4.1: Plumb mask/unmask SGI callbacks Marc Zyngier
2020-02-20 3:32 ` Zenghui Yu
2020-02-14 14:57 ` [PATCH v4 08/20] irqchip/gic-v4.1: Plumb get/set_irqchip_state " Marc Zyngier
2020-02-18 7:00 ` Zenghui Yu
2020-02-18 9:27 ` Marc Zyngier
2020-02-18 15:31 ` Marc Zyngier
2020-02-19 11:50 ` Zenghui Yu
2020-02-19 15:18 ` Zenghui Yu
2020-02-20 3:11 ` Zenghui Yu
2020-02-28 19:37 ` Marc Zyngier
2020-03-01 19:00 ` Marc Zyngier
2020-03-02 8:18 ` Zenghui Yu
2020-03-02 12:09 ` Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 09/20] irqchip/gic-v4.1: Plumb set_vcpu_affinity " Marc Zyngier
2020-02-20 3:37 ` Zenghui Yu
2020-02-28 19:00 ` Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 10/20] irqchip/gic-v4.1: Move doorbell management to the GICv4 abstraction layer Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 11/20] irqchip/gic-v4.1: Add VSGI allocation/teardown Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 12/20] irqchip/gic-v4.1: Add VSGI property setup Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 13/20] irqchip/gic-v4.1: Eagerly vmap vPEs Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 14/20] KVM: arm64: GICv4.1: Let doorbells be auto-enabled Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 15/20] KVM: arm64: GICv4.1: Add direct injection capability to SGI registers Marc Zyngier
2020-02-18 8:46 ` Zenghui Yu
2020-02-18 9:41 ` Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 16/20] KVM: arm64: GICv4.1: Allow SGIs to switch between HW and SW interrupts Marc Zyngier
2020-02-20 3:55 ` Zenghui Yu
2020-02-28 19:16 ` Marc Zyngier
2020-03-02 2:40 ` Zenghui Yu
2020-02-14 14:57 ` [PATCH v4 17/20] KVM: arm64: GICv4.1: Plumb SGI implementation selection in the distributor Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 18/20] KVM: arm64: GICv4.1: Reload VLPI configuration on distributor enable/disable Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 19/20] KVM: arm64: GICv4.1: Allow non-trapping WFI when using HW SGIs Marc Zyngier
2020-02-14 14:57 ` [PATCH v4 20/20] KVM: arm64: GICv4.1: Expose HW-based SGIs in debugfs Marc Zyngier
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