linux-kernel - Re: [PATCH v3 15/16] kvm: x86: ioapic: Lazy update IOAPIC EOI

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] [day] [month] [year] [list]

Date:   Fri, 1 Nov 2019 00:09:03 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     "Suthikulpanit, Suravee" <Suravee.Suthikulpanit@....com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>
Cc:     "rkrcmar@...hat.com" <rkrcmar@...hat.com>,
        "joro@...tes.org" <joro@...tes.org>,
        "vkuznets@...hat.com" <vkuznets@...hat.com>,
        "graf@...zon.com" <graf@...zon.com>,
        "jschoenh@...zon.de" <jschoenh@...zon.de>,
        "karahmed@...zon.de" <karahmed@...zon.de>,
        "rimasluk@...zon.com" <rimasluk@...zon.com>,
        "Grimm, Jon" <Jon.Grimm@....com>
Subject: Re: [PATCH v3 15/16] kvm: x86: ioapic: Lazy update IOAPIC EOI

On 31/10/19 16:17, Suthikulpanit, Suravee wrote:
> What if we change kvm->arch.apicv_state to kvm->arch.apicv_disable_mask 
> and have each bit representing the reason for deactivating APICv.
> 
> For example:
>      #define APICV_DISABLE_MASK_IRQWIN        0
>      #define APICV_DISABLE_MASK_HYPERV        1
>      #define APICV_DISABLE_MASK_PIT_REINJ     2
>      #define APICV_DISABLE_MASK_NESTED        3
> 
> In this case, we activate APICv only if kvm->arch.apicv_disable_mask == 
> 0. This way, we can find out why APICv is deactivated on a particular VM 
> at a particular point in time.

Yes, that also works for me if it makes for an easier implementation.

Paolo