Re: [RFC PATCH v1 3/4] KVM: arm64: GICv4.1: Restore VLPI's pending state to physical side
From: Marc Zyngier <maz@kernel.org>
Date: 2020-12-01 11:50:45
Also in:
kvm, kvmarm, lkml
On 2020-12-01 11:40, Shenming Lu wrote:
On 2020/12/1 18:55, Marc Zyngier wrote:quoted
On 2020-11-30 07:23, Shenming Lu wrote: Hi Shenming,quoted
We are pondering over this problem these days, but still don't get a good solution... Could you give us some advice on this? Or could we move the restoring of the pending states (include the sync from guest RAM and the transfer to HW) to the GIC VM state change handler, which is completely corresponding to save_pending_tables (more symmetric?) and don't expose GICv4...What is "the GIC VM state change handler"? Is that a QEMU thing?Yeah, it is a a QEMU thing...quoted
We don't really have that concept in KVM, so I'd appreciate if you could be a bit more explicit on this.My thought is to add a new interface (to QEMU) for the restoring of the pending states, which is completely corresponding to KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES... And it is called from the GIC VM state change handler in QEMU, which is happening after the restoring (call kvm_vgic_v4_set_forwarding()) but before the starting (running) of the VFIO device.
Right, that makes sense. I still wonder how much the GIC save/restore
stuff differs from other architectures that implement similar features,
such as x86 with VT-D.
It is obviously too late to change the userspace interface, but I wonder
whether we missed something at the time.
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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