From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Xu Subject: Re: [PATCH v2 5/6] KVM: x86: prevent setup of invalid routes Date: Tue, 10 Jan 2017 13:26:48 +0800 Message-ID: <20170110052648.GJ4135@pxdev.xzpeter.org> References: <20161216151006.11776-1-rkrcmar@redhat.com> <20161216151006.11776-6-rkrcmar@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Paolo Bonzini To: Radim =?utf-8?B?S3LEjW3DocWZ?= Return-path: Content-Disposition: inline In-Reply-To: <20161216151006.11776-6-rkrcmar@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Fri, Dec 16, 2016 at 04:10:05PM +0100, Radim Krčmář wrote: > The check in kvm_set_pic_irq() and kvm_set_ioapic_irq() was just a > temporary measure until the code improved enough for us to do this. > > This changes APIC in a case when KVM_SET_GSI_ROUTING is called to set up pic > and ioapic routes before KVM_CREATE_IRQCHIP. Those rules would get overwritten > by KVM_CREATE_IRQCHIP at best, so it is pointless to allow it. Userspaces > hopefully noticed that things don't work if they do that and don't do that. > > Reviewed-by: Paolo Bonzini > Signed-off-by: Radim Krčmář Since we are at here, do we need to protect KVM_SET_GSI_ROUTING in general as well to make sure kernel APIC is there? Like: ---------8<--------- diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 482612b..31141a7 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3057,6 +3057,10 @@ static long kvm_vm_ioctl(struct file *filp, struct kvm_irq_routing_entry *entries = NULL; r = -EFAULT; + + if (!irqchip_in_kernel(kvm)) + goto out; + if (copy_from_user(&routing, argp, sizeof(routing))) goto out; r = -EINVAL; --------->8--------- Thanks, -- peterx