alistair23-linux/Documentation/virtual
Roman Kagan faeb7833ee kvm: x86: hyperv: guest->host event signaling via eventfd
In Hyper-V, the fast guest->host notification mechanism is the
SIGNAL_EVENT hypercall, with a single parameter of the connection ID to
signal.

Currently this hypercall incurs a user exit and requires the userspace
to decode the parameters and trigger the notification of the potentially
different I/O context.

To avoid the costly user exit, process this hypercall and signal the
corresponding eventfd in KVM, similar to ioeventfd.  The association
between the connection id and the eventfd is established via the newly
introduced KVM_HYPERV_EVENTFD ioctl, and maintained in an
(srcu-protected) IDR.

Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
[asm/hyperv.h changes approved by KY Srinivasan. - Radim]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2018-03-06 18:40:36 +01:00
..
kvm kvm: x86: hyperv: guest->host event signaling via eventfd 2018-03-06 18:40:36 +01:00
uml Documentation: Update path to sysrq.txt 2017-03-03 15:48:38 -07:00
00-INDEX virtual: Documentation: simplify and generalize paravirt_ops.txt 2015-02-13 17:15:44 +10:30
paravirt_ops.txt virtual: Documentation: simplify and generalize paravirt_ops.txt 2015-02-13 17:15:44 +10:30