| 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
| ||
|
Date: Mon, 22 Sep 2014 17:08:12 -0300 From: Marcelo Tosatti <mtosatti@...hat.com> To: David Matlack <dmatlack@...gle.com> Cc: Gleb Natapov <gleb@...nel.org>, Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH] kvm: don't take vcpu mutex for obviously invalid vcpu ioctls On Fri, Sep 19, 2014 at 04:03:25PM -0700, David Matlack wrote: > vcpu ioctls can hang the calling thread if issued while a vcpu is > running. There is a mutex per-vcpu, so thats expected, OK... > If we know ioctl is going to be rejected as invalid anyway, > we can fail before trying to take the vcpu mutex. Consider a valid ioctl that takes the vcpu mutex. If you need immediate access for that valid ioctl, it is necessary to interrupt thread which KVM_RUN ioctl executes. So knowledge of whether KVM_RUN is being executed is expected in userspace (either that or ask the KVM_RUN thread to run the ioctl for you, as qemu does). Can't see why having different behaviour for valid/invalid ioctls is a good thing. > This patch does not change functionality, it just makes invalid ioctls > fail faster. Should not be executing vcpu ioctls without interrupt KVM_RUN in the first place. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists