Hyper-V identifies vCPUs by Virtual Processor (VP) index which can be
queried by the guest via HV_X64_MSR_VP_INDEX msr. It is defined by the
spec as a sequential number which can't exceed the maximum number of
vCPUs per VM.
It has to be owned by QEMU in order to preserve it across migration.
However, the initial implementation in KVM didn't allow to set this
msr, and KVM used its own notion of VP index. Fortunately, the way
vCPUs are created in QEMU/KVM makes it likely that the KVM value is
equal to QEMU cpu_index.
So choose cpu_index as the value for vp_index, and push that to KVM on
kernels that support setting the msr. On older ones that don't, query
the kernel value and assert that it's in sync with QEMU.
Besides, since handling errors from vCPU init at hotplug time is
impossible, disable vCPU hotplug.
This patch also introduces accessor functions to encapsulate the mapping
between a vCPU and its vp_index.
Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>
Message-Id: <20180702134156.13404-3-rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
We've currently got 18 architectures in QEMU, and thus 18 target-xxx
folders in the root folder of the QEMU source tree. More architectures
(e.g. RISC-V, AVR) are likely to be included soon, too, so the main
folder of the QEMU sources slowly gets quite overcrowded with the
target-xxx folders.
To disburden the main folder a little bit, let's move the target-xxx
folders into a dedicated target/ folder, so that target-xxx/ simply
becomes target/xxx/ instead.
Acked-by: Laurent Vivier <laurent@vivier.eu> [m68k part]
Acked-by: Bastian Koppelmann <kbastian@mail.uni-paderborn.de> [tricore part]
Acked-by: Michael Walle <michael@walle.cc> [lm32 part]
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> [s390x part]
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> [s390x part]
Acked-by: Eduardo Habkost <ehabkost@redhat.com> [i386 part]
Acked-by: Artyom Tarasenko <atar4qemu@gmail.com> [sparc part]
Acked-by: Richard Henderson <rth@twiddle.net> [alpha part]
Acked-by: Max Filippov <jcmvbkbc@gmail.com> [xtensa part]
Reviewed-by: David Gibson <david@gibson.dropbear.id.au> [ppc part]
Acked-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> [crisµblaze part]
Acked-by: Guan Xuetao <gxt@mprc.pku.edu.cn> [unicore32 part]
Signed-off-by: Thomas Huth <thuth@redhat.com>
