Re: [PATCH 0/3] KVM: arm: Implement software vGICv2 emulation

[Marc Zyngier <marc.zyngier@arm.com>]

Hi Pavel,

On 29/06/15 10:53, Pavel Fedin wrote:
> Some hardware (like Raspberry Pi 2) is capable of running KVM, however lacks
> functional vGIC registers. This series introduces software vGIC emulation for
> such machines, allowing to fully use virtualization capabilities

I'm really not keen on any of this. The RPi-2 is mostly unsupported in
mainline, and not only lacks the vGIC, but doesn't have a GIC at all.
This would break ongoing developments (inability to properly support
EOImode=1, to preserve the active state for shared devices like timers).

As far as I'm concerned, this hardware is not architecturally compliant
and the solution is to use userspace emulation (QEMU provides a GIC
model). Taking these patches would keep us stuck in the past.

I'm sure whoever maintains the RPi kernel will be glad to take these
patches on top of the pile of stuff they keep out of tree.

Thanks,

	M.

> Pavel Fedin (3):
>   KVM: arm: Add basic infrastructure for software vGIC emulation
>   KVM: arm: Introduce software emulation of vGICv2 CPU interface
>   KVM: arm: Enable vGICv2 software emulation
> 
>  include/kvm/arm_vgic.h      |   4 ++
>  virt/kvm/arm/vgic-v2-emul.c |  60 +++++++++++++++--
>  virt/kvm/arm/vgic-v2.c      |  29 ++++----
>  virt/kvm/arm/vgic.c         | 159 +++++++++++++++++++++++++++++++++-----------
>  virt/kvm/arm/vgic.h         |   3 +
>  5 files changed, 196 insertions(+), 59 deletions(-)
> 


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