Re: [RFC PATCH 4/4] KVM: x86: Add support for local interrupt requests from userspace

[Steve Rutherford <srutherford@google.com>]

On Wed, May 13, 2015 at 09:22:21AM +0200, Paolo Bonzini wrote:
> 
> 
> On 13/05/2015 03:47, Steve Rutherford wrote:
> > In order to enable userspace PIC support, the userspace PIC needs to
> > be able to inject local interrupt requests.
> > 
> > This adds the ioctl KVM_REQUEST_LOCAL_INTERRUPT and kvm exit
> > KVM_EXIT_GET_EXTINT.
> > 
> > The vm ioctl KVM_REQUEST_LOCAL_INTERRUPT makes a KVM_REQ_EVENT request
> > on the BSP, which causes the BSP to exit to userspace to fetch the
> > vector of the underlying external interrupt, which the BSP then
> > injects into the guest. This matches the PIC spec, and is necessary to
> > boot Windows.
> > 
> > Boots and passes the KVM unit tests on intel x86 with the
> > PIC/PIT/IOAPIC in userspace (under a non-QEMU VMM). Boots and passes
> > the KVM unit tests under normal conditions as well.
> > 
> > SVM support and device assignment are untested with this feature
> > enabled, but testing for both is in the works.
> > 
> > Compiles for ARM/x86/PPC.
> 
> This may be ENOCOFFEE, but where is extint.vector read?

Uhhh. It's not. Something's wrong here. Looks like I dropped some lines in porting these patches. Somehow this still passes the KVM unit tests o.O

I'll track down the error. 

Steve
> 
> Could you use KVM_INTERRUPT to set KVM_REQUEST_LOCAL_INTERRUPT _and_ the
> interrupt vector at the same time?  This is exactly the logic that is
> used for !irqchip, and it should work for the EXTINT case as well.
> 
> Paolo