> -----Original Message----- > From: Alex Williamson [mailto:alex.williamson@xxxxxxxxxx] > Sent: Wednesday, November 26, 2014 12:10 AM > To: Eric Auger > Cc: Wu, Feng; pbonzini@xxxxxxxxxx; gleb@xxxxxxxxxx; kvm@xxxxxxxxxxxxxxx > Subject: Re: [RFC PATCH v2 1/2] KVM: kvm-vfio: User API for VT-d > Posted-Interrupts > > On Tue, 2014-11-25 at 16:01 +0100, Eric Auger wrote: > > On 11/25/2014 01:23 PM, Feng Wu wrote: > > > This patch adds and documents a new attribute > > > KVM_DEV_VFIO_DEVICE_POSTING_IRQ in KVM_DEV_VFIO_DEVICE group. > > > This new attribute is used for VT-d Posted-Interrupts. > > > > > > When guest OS changes the interrupt configuration for an > > > assigned device, such as, MSI/MSIx data/address fields, > > > QEMU will use this IRQ attribute to tell KVM to update the > > > related IRTE according the VT-d Posted-Interrrupts Specification, > > > such as, the guest vector should be updated in the related IRTE. > > > > > > Signed-off-by: Feng Wu <feng.wu@xxxxxxxxx> > > > --- > > > Documentation/virtual/kvm/devices/vfio.txt | 9 +++++++++ > > > include/uapi/linux/kvm.h | 10 ++++++++++ > > > 2 files changed, 19 insertions(+), 0 deletions(-) > > > > > > diff --git a/Documentation/virtual/kvm/devices/vfio.txt > b/Documentation/virtual/kvm/devices/vfio.txt > > > index f7aff29..39dee86 100644 > > > --- a/Documentation/virtual/kvm/devices/vfio.txt > > > +++ b/Documentation/virtual/kvm/devices/vfio.txt > > > @@ -42,3 +42,12 @@ activated before VFIO_DEVICE_SET_IRQS has been > called to trigger the IRQ > > > or associate an eventfd to it. Unforwarding can only be called while the > > > signaling has been disabled with VFIO_DEVICE_SET_IRQS. If this condition > is > > > not satisfied, the command returns an -EBUSY. > > > + > > > + KVM_DEV_VFIO_DEVICE_POSTING_IRQ: Use posted interrtups > mechanism to post > > > + the IRQ to guests. > > > +For this attribute, kvm_device_attr.addr points to a kvm_posted_intr > struct. > > > + > > > +When guest OS changes the interrupt configuration for an assigned device, > > > +such as, MSI/MSIx data/address fields, QEMU will use this IRQ attribute > > > +to tell KVM to update the related IRTE according the VT-d > Posted-Interrrupts > > > +Specification, such as, the guest vector should be updated in the related > IRTE. > > > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > > > index a269a42..e5f86ad 100644 > > > --- a/include/uapi/linux/kvm.h > > > +++ b/include/uapi/linux/kvm.h > > > @@ -949,6 +949,7 @@ struct kvm_device_attr { > > > #define KVM_DEV_VFIO_DEVICE 2 > > > #define KVM_DEV_VFIO_DEVICE_FORWARD_IRQ 1 > > > #define KVM_DEV_VFIO_DEVICE_UNFORWARD_IRQ 2 > > > +#define KVM_DEV_VFIO_DEVICE_POSTING_IRQ 3 > > > > > > enum kvm_device_type { > > > KVM_DEV_TYPE_FSL_MPIC_20 = 1, > > > @@ -973,6 +974,15 @@ struct kvm_arch_forwarded_irq { > > > __u32 gsi; /* gsi, ie. virtual IRQ number */ > > > }; > > > > > > +struct kvm_posted_intr { > > > + __u32 argsz; > > > + __u32 fd; /* file descriptor of the VFIO device */ > > > + __u32 index; /* VFIO device IRQ index */ > > > + __u32 start; > > > + __u32 count; > > > + int virq[0]; /* gsi, ie. virtual IRQ number */ > > > +}; > > Hi Feng, > > > > This struct could be used by arm code too. If Alex agrees I could use > > that one instead. We just need to find a common sensible name > > Yep, the interface might as well support batch setup. The vfio code > uses -1 for teardown if we want to avoid FORWARD vs UNFORWARD we could > let the data in the structure define which operation to do. Ideally the > code in virt/kvm/vfio.c would be almost entirely shared and just make > different arch_foo() callouts. The PCI smarts in 2/2 here should > probably be moved out to that same arch_ code. Thanks, > > Alex That would be great if we share the same data structure! Thanks, Feng ��.n��������+%������w��{.n�����o�^n�r������&��z�ޗ�zf���h���~����������_��+v���)ߣ�
