On Wed, 2011-12-07 at 18:28 +1100, Matt Evans wrote: > On 07/12/11 18:24, Alexander Graf wrote: > > > > On 07.12.2011, at 08:19, Matt Evans <[email protected]> wrote: > > > >> On 07/12/11 17:34, Sasha Levin wrote: > >>> On Wed, 2011-12-07 at 17:17 +1100, Matt Evans wrote: > >>>> On 06/12/11 19:20, Sasha Levin wrote: > >>>>> Why is it getting moved out of generic code? > >>>>> > >>>>> This is used to determine the maximum amount of vcpus supported by the > >>>>> host for a single guest, and as far as I know KVM_CAP_NR_VCPUS and > >>>>> KVM_CAP_MAX_VCPUS are not arch specific. > >>>> > >>>> I checked api.txt and you're right, it isn't arch-specific. I assumed > >>>> it was, > >>>> because PPC KVM doesn't support it ;-) I've dropped this patch and in > >>>> its place > >>>> implemented the api.txt suggestion of "if KVM_CAP_NR_VCPUS fails, use 4" > >>>> instead > >>>> of die(); you'll see that when I repost. > >>>> > >>>> This will have the effect of PPC being limited to 4 CPUs until the kernel > >>>> supports that CAP. (I'll see about this part too.) > >>> > >>> I went to look at which limitation PPC places on amount of vcpus in > >>> guest, and saw this in kvmppc_core_vcpu_create() in the book3s code: > >>> > >>> vcpu = kvmppc_core_vcpu_create(kvm, id); > >>> vcpu->arch.wqp = &vcpu->wq; > >>> if (!IS_ERR(vcpu)) > >>> kvmppc_create_vcpu_debugfs(vcpu, id); > >>> > >>> This is wrong, right? The VCPU is dereferenced before actually checking > >>> that it's not an error. > >> > >> Yeah, that's b0rk. Alex, a patch below. :) > > > > Thanks :). Will apply asap but don't have a real keyboard today :). > > Ha! Voice control on your phone, what could go wrong? > > > I suppose this is stable material? > > Good idea, (and if we're formal, > Signed-off-by: Matt Evans <[email protected]> > ). I suppose no one's seen a vcpu fail to be created, yet.
I also got another one, but it's **completely untested** (not even compiled). Alex, Matt, any chance one of you can loan a temporary ppc shell for the upcoming tests of KVM tool/ppc KVM? --- From: Sasha Levin <[email protected]> Date: Wed, 7 Dec 2011 10:24:56 +0200 Subject: [PATCH] KVM: PPC: Use the vcpu kmem_cache when allocating new VCPUs Currently the code kzalloc()s new VCPUs instead of using the kmem_cache which is created when KVM is initialized. Modify it to allocate VCPUs from that kmem_cache. Signed-off-by: Sasha Levin <[email protected]> --- arch/powerpc/kvm/book3s_hv.c | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 0cb137a..e309099 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -411,7 +411,7 @@ struct kvm_vcpu *kvmppc_core_vcpu_create(struct kvm *kvm, unsigned int id) goto out; err = -ENOMEM; - vcpu = kzalloc(sizeof(struct kvm_vcpu), GFP_KERNEL); + vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL); if (!vcpu) goto out; @@ -463,7 +463,7 @@ struct kvm_vcpu *kvmppc_core_vcpu_create(struct kvm *kvm, unsigned int id) return vcpu; free_vcpu: - kfree(vcpu); + kmem_cache_free(kvm_vcpu_cache, vcpu); out: return ERR_PTR(err); } @@ -471,7 +471,7 @@ out: void kvmppc_core_vcpu_free(struct kvm_vcpu *vcpu) { kvm_vcpu_uninit(vcpu); - kfree(vcpu); + kmem_cache_free(kvm_vcpu_cache, vcpu); } static void kvmppc_set_timer(struct kvm_vcpu *vcpu) -- Sasha. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
