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/qemu/include/hw/ppc/
H A Dspapr_xive.h0c575703e487b6e36d226b67e0c8d08c004ce998 Mon May 13 08:42:34 UTC 2019 Cédric Le Goater <clg@kaod.org> spapr/xive: add hcall support when under KVM

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>
/qemu/hw/intc/
H A Dspapr_xive_kvm.c0c575703e487b6e36d226b67e0c8d08c004ce998 Mon May 13 08:42:34 UTC 2019 Cédric Le Goater <clg@kaod.org> spapr/xive: add hcall support when under KVM

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>
H A Dspapr_xive.c0c575703e487b6e36d226b67e0c8d08c004ce998 Mon May 13 08:42:34 UTC 2019 Cédric Le Goater <clg@kaod.org> spapr/xive: add hcall support when under KVM

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>