linux-kernel - Re: [PATCH 5/5] x86/kvm: Add KVM_FEATURE_MSI_EXT_DEST

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <832c2d4c11cd99382782474f51d15889ffa24407.camel@infradead.org>
Date:   Tue, 13 Oct 2020 11:53:04 +0100
From:   David Woodhouse <dwmw2@...radead.org>
To:     Thomas Gleixner <tglx@...utronix.de>, x86@...nel.org,
        Marc Zyngier <maz@...nel.org>
Cc:     kvm <kvm@...r.kernel.org>, Paolo Bonzini <pbonzini@...hat.com>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 5/5] x86/kvm: Add KVM_FEATURE_MSI_EXT_DEST_ID

On Tue, 2020-10-13 at 12:46 +0200, Thomas Gleixner wrote:
> And after becoming more awake, that wont work anyway because there is
> more than one IR domain, so there is no way to return an error "You
> forgot to register" obviously.
> 
> But the APIC id (32768) valid check is also broken because IR can be
> enabled even without X2APIC.

Nope, it's perfectly OK to allow HPET and I/OAPIC to be parented in the
x86_vector_domain in that case, regardless of IR.

The *actual* criterion for x86_vector_select() returning zero to say 
"don't use me" is "could there be CPUs in the system which can't be
reached through x86_vector_msi_compose_msg()?". It's not really about
IR at all.

The apic_id_valid(32768) check is checking precisely the right thing.

Download attachment "smime.p7s" of type "application/x-pkcs7-signature" (5174 bytes)