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Re: [Qemu-devel] [PATCH v3 00/20] GICv3 emulation

From: Peter Maydell
Subject: Re: [Qemu-devel] [PATCH v3 00/20] GICv3 emulation
Date: Wed, 15 Jun 2016 15:06:21 +0100

On 15 June 2016 at 15:02, Shannon Zhao <address@hidden> wrote:
> I'll try tomorrow. By the way, if we disable secure extension, will the
> problem disappear?

No; it's because the secure extension is disabled that the problem
exists. If security is disabled then the guest gets to use both
group 0 and group 1 IRQs (and if it wants to use IRQs as all group
1 it must configure them itself). If security is enabled then the
guest will always being using group 1 IRQs, and the secure firmware
is what will configure the IRQs for the NS guest as group 1
(since the group registers aren't accessible to NS). So if the
guest forgets to configure the IRQ groups it will work fine
in a system with the security extensions, but won't boot in one
without. [It will also boot OK in KVM because of a KVM bug/misfeature
where KVM's GICv3 only emulates group 1 interrupts.]

-- PMM

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