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Re: [Qemu-devel] [PATCH] target/arm/kvm: gic: Prevent creating userspace
From: |
Christoffer Dall |
Subject: |
Re: [Qemu-devel] [PATCH] target/arm/kvm: gic: Prevent creating userspace GICv3 with KVM |
Date: |
Tue, 6 Feb 2018 10:06:59 +0100 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
Hi Philippe,
On Mon, Feb 05, 2018 at 09:10:48PM -0300, Philippe Mathieu-Daudé wrote:
>
> On 02/01/2018 05:53 PM, Christoffer Dall wrote:
> > KVM doesn't support emulating a GICv3 in userspace, only GICv2. We
> > currently attempt this anyway, and as a result a KVM guest doesn't
> > receive interrupts and the user is left wondering why. Report an error
> > to the user if this particular combination is requested.
> >
> > Signed-off-by: Christoffer Dall <address@hidden>
> > ---
> > target/arm/kvm_arm.h | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/target/arm/kvm_arm.h b/target/arm/kvm_arm.h
> > index ff53e9fafb..cfb7e5af72 100644
> > --- a/target/arm/kvm_arm.h
> > +++ b/target/arm/kvm_arm.h
> > @@ -234,6 +234,10 @@ static inline const char *gicv3_class_name(void)
>
> Any reason why these functions are inlined in this include?
Not really sure what you mean? What do you think would be a better
approach?
>
> Also - not related to your patch - while gicv3_class_name() is
> self-explicit, gic_class_name() isn't (to me at least).
I think I tend to see 'gic' as GICv2 and 'gicv3' as GICv3 in QEMU, but I
don't remember the details of how you make the GIC be a proper GICv2 vs.
the 11mpcore version thingy.
>
> There are many check for gic_version 1/2/3 in virt.c, which we could
> clean using more generic functions such gic_class_name(int gic_version)
> and Co.
Possibly. Do note, that checking "which version of the GIC does this
board contain" is a separate thing from "which particular mechanism do I
use to emulate the GIC".
>
> > exit(1);
> > #endif
> > } else {
> > + if (kvm_enabled()) {
> > + error_report("Userspace GICv3 is not supported with KVM");
> > + exit(1);
>
> Reviewed-by: Philippe Mathieu-Daudé <address@hidden>
>
> > + }
> > return "arm-gicv3";
> > }
> > }
> >
>
Thanks!
-Christoffer
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