From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: pre-preparation for in-kernel device model Date: Tue, 05 Jun 2007 14:32:38 +0300 Message-ID: <466549D6.903@qumranet.com> References: <10EA09EFD8728347A513008B6B0DA77A018E0662@pdsmsx411.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel To: "Dong, Eddie" Return-path: In-Reply-To: <10EA09EFD8728347A513008B6B0DA77A018E0662-wq7ZOvIWXbNpB2pF5aRoyrfspsVTdybXVpNB7YpNyf8@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Dong, Eddie wrote: > When in kernel device model is introduced, the guest interrupt status > may get changed when after it injected an IRQ and thus guest see a > messed interrupt state. This patch tries to disable irq at that window > to avoid the confusion. > > > Signed-off-by: Yaozu (Eddie) Dong > > > > diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c > index ef9e32b..0cf6ea7 100644 > --- a/drivers/kvm/vmx.c > +++ b/drivers/kvm/vmx.c > @@ -1977,9 +1977,6 @@ static int vmx_vcpu_run(struct kvm_vcpu *vcpu, > struct kvm_run *kvm_run) > int r; > > preempted: > - if (!vcpu->mmio_read_completed) > - do_interrupt_requests(vcpu, kvm_run); > - > if (vcpu->guest_debug.enabled) > kvm_guest_debug_pre(vcpu); > > @@ -1996,9 +1993,16 @@ again: > */ > vmcs_writel(HOST_CR0, read_cr0()); > > + /* > + * Disable interrupt to avoid future in kernel > + * APIC interrupt state confuse. > + */ > + asm ( "pushf; cli \n\t"); > + if (!vcpu->mmio_read_completed) > + do_interrupt_requests(vcpu, kvm_run); > + > This is broken. pushf changes %rsp, and if the compiler uses %rsp based addressing (-fomit-frame-pointer), it will use the wrong addresses for variables. Suggest using local_irq_disable()/local_irq_enable() (and removing pushf/popf from the entry/exit sequence). -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/