XIVE hcalls are all redirected to QEMU as none are on a fast path.
When necessary, QEMU invokes KVM through specific ioctls to perform
host operations. QEMU should have done the necessary checks before
calling KVM and, in case of failure, H_HARDWARE is simply returned.
H_INT_ESB is a special case that could have been handled under KVM
but the impact on performance was low when under QEMU. Here are some
figures :
kernel irqchip OFF ON
H_INT_ESB KVM QEMU
rtl8139 (LSI ) 1.19 1.24 1.23 Gbits/sec
virtio 31.80 42.30 -- Gbits/sec
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Message-Id: <20190513084245.25755-4-clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
0c575703e4