From c05c4186bbe4e99d64e8a36f7ca7f480da5d109f Mon Sep 17 00:00:00 2001 From: Jens Freimann Date: Mon, 7 Oct 2013 16:13:45 +0200 Subject: KVM: s390: add floating irq controller This patch adds a floating irq controller as a kvm_device. It will be necessary for migration of floating interrupts as well as for hardening the reset code by allowing user space to explicitly remove all pending floating interrupts. Signed-off-by: Jens Freimann Reviewed-by: Cornelia Huck Signed-off-by: Christian Borntraeger --- Documentation/virtual/kvm/devices/s390_flic.txt | 36 +++++++++++++++++++++++++ 1 file changed, 36 insertions(+) create mode 100644 Documentation/virtual/kvm/devices/s390_flic.txt (limited to 'Documentation/virtual/kvm/devices/s390_flic.txt') diff --git a/Documentation/virtual/kvm/devices/s390_flic.txt b/Documentation/virtual/kvm/devices/s390_flic.txt new file mode 100644 index 000000000000..6b557953066a --- /dev/null +++ b/Documentation/virtual/kvm/devices/s390_flic.txt @@ -0,0 +1,36 @@ +FLIC (floating interrupt controller) +==================================== + +FLIC handles floating (non per-cpu) interrupts, i.e. I/O, service and some +machine check interruptions. All interrupts are stored in a per-vm list of +pending interrupts. FLIC performs operations on this list. + +Only one FLIC instance may be instantiated. + +FLIC provides support to +- add interrupts (KVM_DEV_FLIC_ENQUEUE) +- inspect currently pending interrupts (KVM_FLIC_GET_ALL_IRQS) +- purge all pending floating interrupts (KVM_DEV_FLIC_CLEAR_IRQS) + +Groups: + KVM_DEV_FLIC_ENQUEUE + Passes a buffer and length into the kernel which are then injected into + the list of pending interrupts. + attr->addr contains the pointer to the buffer and attr->attr contains + the length of the buffer. + The format of the data structure kvm_s390_irq as it is copied from userspace + is defined in usr/include/linux/kvm.h. + + KVM_DEV_FLIC_GET_ALL_IRQS + Copies all floating interrupts into a buffer provided by userspace. + When the buffer is too small it returns -ENOMEM, which is the indication + for userspace to try again with a bigger buffer. + All interrupts remain pending, i.e. are not deleted from the list of + currently pending interrupts. + attr->addr contains the userspace address of the buffer into which all + interrupt data will be copied. + attr->attr contains the size of the buffer in bytes. + + KVM_DEV_FLIC_CLEAR_IRQS + Simply deletes all elements from the list of currently pending floating + interrupts. No interrupts are injected into the guest. -- cgit v1.2.3