From: Gleb Natapov <gleb@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: [PATCH] x86: let userspace inject interrupts into the local APIC
Date: Tue, 19 Mar 2013 20:50:26 +0200 [thread overview]
Message-ID: <20130319185025.GM19292@redhat.com> (raw)
In-Reply-To: <5148B0DC.9000609@redhat.com>
On Tue, Mar 19, 2013 at 07:39:24PM +0100, Paolo Bonzini wrote:
> Il 19/03/2013 19:13, Gleb Natapov ha scritto:
> >> > There is no way for userspace to inject interrupts into a VCPU's
> >> > local APIC, which is important in order to inject INITs coming from
> >> > the chipset. KVM_INTERRUPT is currently disabled when the in-kernel
> >> > local APIC is used, so we can repurpose it. The shorthand destination
> >> > field must contain APIC_DEST_SELF, which has a double effect: first,
> >> > the ICR2 register is not used and the 32-bit field of KVM_INTERRUPT is
> >> > enough; second, it ensures that the valid range of the irq field is
> >> > distinct in the userspace-APIC and kernel-APIC cases.
> >> >
> > Init coming from triggering INIT# line should not be modeled as INIT coming from
> > APIC.
>
> Then Jan's patch was wrong, and INIT should not have been an apic event
> (perhaps SIPI should).
>
If it goes through APIC it is. Also the problem with reusing KVM_INTERRUPT is
that it is synchronous interface but INIT# is asynchronous. Shouldn't be a big
deal though.
> > In fact INIT cannot be send using SELF shorthand.
>
> Where does the SDM say that?
>
Table 10-3.
--
Gleb.
next prev parent reply other threads:[~2013-03-19 18:50 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-19 15:51 [PATCH] x86: let userspace inject interrupts into the local APIC Paolo Bonzini
2013-03-19 18:13 ` Gleb Natapov
2013-03-19 18:39 ` Paolo Bonzini
2013-03-19 18:50 ` Gleb Natapov [this message]
2013-03-19 20:22 ` Paolo Bonzini
2013-03-20 10:56 ` Gleb Natapov
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