On Tue, Jul 14, 2020 at 08:52:43AM +0800, Zhu, Lingshan wrote:
>
> On 7/13/2020 6:52 PM, Michael S. Tsirkin wrote:
>
> On Mon, Jul 13, 2020 at 04:13:35PM +0800, Jason Wang wrote:
>
> On 2020/7/13 上午5:06, Michael S. Tsirkin wrote:
>
> On Sun, Jul 12, 2020 at 10:49:21PM +0800, Zhu Lingshan wrote:
>
> We used to detect assigned device via VFIO manipulated device
> conters. This is less flexible consider VFIO is not the only
> interface for assigned device. vDPA devices has dedicated
> backed hardware as well. So this patch tries to detect
> the assigned device via irqbypass manager.
>
> We will increase/decrease the assigned device counter in
> kvm/x86.
> Both vDPA and VFIO would go through this code path.
>
> This code path only affect x86 for now.
>
> Signed-off-by: Zhu Lingshan <[email protected]>
>
> I think it's best to leave VFIO alone. Add appropriate APIs for
> VDPA,
> worry about converting existing users later.
>
>
>
> Just to make sure I understand, did you mean:
>
> 1) introduce another bridge for vDPA
>
> or
>
> 2) only detect vDPA via bypass manager? (we can leave VFIO code as
> is, then
> the assigned device counter may increase/decrease twice if VFIO use
> irq
> bypass manager which should be no harm).
>
> Thanks
>
> 2 is probably easier to justify. 1 would depend on the specific bridge
> proposed.
>
> Thanks Michael, so we should just drop changes in vfio, just increase /
> decrease
> the counter in irq bypass manager. right?
>
> Thanks
I don't see any issue with that.
>
>
> ---
> arch/x86/kvm/x86.c | 10 ++++++++--
> virt/kvm/vfio.c | 2 --
> 2 files changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 00c88c2..20c07d3 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -10624,11 +10624,17 @@ int
> kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *cons,
> {
> struct kvm_kernel_irqfd *irqfd =
> container_of(cons, struct kvm_kernel_irqfd,
> consumer);
> + int ret;
> irqfd->producer = prod;
> + kvm_arch_start_assignment(irqfd->kvm);
> + ret = kvm_x86_ops.update_pi_irte(irqfd->kvm,
> + prod->irq,
> irqfd->gsi, 1);
> +
> + if (ret)
> + kvm_arch_end_assignment(irqfd->kvm);
> - return kvm_x86_ops.update_pi_irte(irqfd->kvm,
> - prod->irq,
> irqfd->gsi, 1);
> + return ret;
> }
> void kvm_arch_irq_bypass_del_producer(struct
> irq_bypass_consumer *cons,
> diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
> index 8fcbc50..111da52 100644
> --- a/virt/kvm/vfio.c
> +++ b/virt/kvm/vfio.c
> @@ -226,7 +226,6 @@ static int kvm_vfio_set_group(struct
> kvm_device *dev, long attr, u64 arg)
> list_add_tail(&kvg->node, &kv->group_list);
> kvg->vfio_group = vfio_group;
> - kvm_arch_start_assignment(dev->kvm);
> mutex_unlock(&kv->lock);
> @@ -254,7 +253,6 @@ static int kvm_vfio_set_group(struct
> kvm_device *dev, long attr, u64 arg)
> continue;
> list_del(&kvg->node);
> - kvm_arch_end_assignment(dev->kvm);
> #ifdef CONFIG_SPAPR_TCE_IOMMU
>
> kvm_spapr_tce_release_vfio_group(dev->kvm,
>
> kvg->vfio_group);
> --
> 1.8.3.1
>
