On 10/01/2013 01:36 PM, Alexander Graf wrote:
On 10/01/2013 01:26 PM, Aneesh Kumar K.V wrote:
Alexander Graf<agraf@xxxxxxx> writes:
On 09/30/2013 03:09 PM, Aneesh Kumar K.V wrote:
Alexander Graf<agraf@xxxxxxx> writes:
On 27.09.2013, at 12:52, Aneesh Kumar K.V wrote:
"Aneesh Kumar K.V"<aneesh.kumar@xxxxxxxxxxxxxxxxxx> writes:
Hi All,
This patch series support enabling HV and PR KVM together in the
same kernel. We
extend machine property with new property "kvm_type". A value of
1 will force HV
KVM and 2 PR KVM. The default value is 0 which will select the
fastest KVM mode.
ie, HV if that is supported otherwise PR.
With Qemu command line having
-machine pseries,accel=kvm,kvm_type=1
[root@llmp24l02 qemu]# bash ../qemu
failed to initialize KVM: Invalid argument
[root@llmp24l02 qemu]# modprobe kvm-pr
[root@llmp24l02 qemu]# bash ../qemu
failed to initialize KVM: Invalid argument
[root@llmp24l02 qemu]# modprobe kvm-hv
[root@llmp24l02 qemu]# bash ../qemu
now with
-machine pseries,accel=kvm,kvm_type=2
[root@llmp24l02 qemu]# rmmod kvm-pr
[root@llmp24l02 qemu]# bash ../qemu
failed to initialize KVM: Invalid argument
[root@llmp24l02 qemu]#
[root@llmp24l02 qemu]# modprobe kvm-pr
[root@llmp24l02 qemu]# bash ../qemu
if don't specify kvm_type machine property, it will take a
default value 0,
which means fastest supported.
Related qemu patch
commit 8d139053177d48a70cb710b211ea4c2843eccdfb
Author: Aneesh Kumar K.V<aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Date: Mon Sep 23 12:28:37 2013 +0530
kvm: Add a new machine property kvm_type
Targets like ppc64 support different type of KVM, one which use
hypervisor mode and the other which doesn't. Add a new machine
property kvm_type that helps in selecting the respective ones
Signed-off-by: Aneesh Kumar
K.V<aneesh.kumar@xxxxxxxxxxxxxxxxxx>
This really is too early, as we can't possibly run in HV mode for
non-pseries machines, so the interpretation (or at least sanity
checking) of what values are reasonable should occur in the
machine. That's why it's a variable in the "machine opts".
With the current code CREATE_VM will fail, because we won't have
kvm-hv.ko loaded and trying to create a vm with type 1 will fail.
Now the challenge related to moving that to machine_init or later
is, we
depend on HV or PR callback early in CREATE_VM. With the changes we
have
int kvmppc_core_init_vm(struct kvm *kvm)
{
#ifdef CONFIG_PPC64
INIT_LIST_HEAD(&kvm->arch.spapr_tce_tables);
INIT_LIST_HEAD(&kvm->arch.rtas_tokens);
#endif
return kvm->arch.kvm_ops->init_vm(kvm);
}
Also the mmu notifier callback do end up calling kvm_unmap_hva etc
which
are all HV/PR dependent.
Yes, so we should verify in the machine models that we're runnable with
the currently selected type at least, to give the user a sensible error
message.
Something like the below
I like that one a lot. Andreas, Paolo, what do you think?
To clarify this a bit more, this patch is missing a few critical pieces:
1) The default implementation for the kvm_type callback needs to
error out when kvm_type is set to anything
2) All non-papr-non-e500-PPC machines should force "PR only" mode and
bail out on anything else
3) We're missing sensible error messages for the user still when the
VM could not get created
but I like the overall concept :).
Alex
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