| Subject | Re: [PATCH v5 01/23] irqchip/gic-v3: Use SGIs without active state if offered | From | Zenghui Yu <> | Date | Thu, 12 Mar 2020 14:30:28 +0800 |
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Hi Marc,
On 2020/3/5 4:33, 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).
I still can't find the description of these two bits in IHI0069F. Are they actually architected and will be available in the future version of the spec? I want to confirm it again since this has a great impact on the KVM code, any pointers?
Thanks, Zenghui
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