From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Graf Subject: Re: [PATCH 07/28] kvm tools: Move 'kvm__recommended_cpus' to arch-specific code Date: Tue, 20 Dec 2011 16:20:37 +0100 Message-ID: References: <4EDD8E73.8040505@ozlabs.org> <1323159616.3882.7.camel@lappy> <4EDF04F4.40805@ozlabs.org> <1323239695.8489.25.camel@lappy> <4EDF138E.6040703@ozlabs.org> Mime-Version: 1.0 (Apple Message framework v1084) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8BIT Cc: Sasha Levin , kvm@vger.kernel.org, kvm-ppc@vger.kernel.org To: Matt Evans Return-path: In-Reply-To: <4EDF138E.6040703@ozlabs.org> Sender: kvm-ppc-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 07.12.2011, at 08:19, Matt Evans 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. :) > > > Cheers, > > > Matt > > --- > Subject: [PATCH] KVM: PPC: Fix vcpu_create dereference before validity check. > > > Signed-off-by: Matt Evans Thanks, applied to kvm-ppc-next with an actual patch description added. Alex > --- > arch/powerpc/kvm/powerpc.c | 5 +++-- > 1 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c > index 084d1c5..7c7220c 100644 > --- a/arch/powerpc/kvm/powerpc.c > +++ b/arch/powerpc/kvm/powerpc.c > @@ -285,9 +285,10 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id) > { > struct kvm_vcpu *vcpu; > vcpu = kvmppc_core_vcpu_create(kvm, id); > - vcpu->arch.wqp = &vcpu->wq; > - if (!IS_ERR(vcpu)) > + if (!IS_ERR(vcpu)) { > + vcpu->arch.wqp = &vcpu->wq; > kvmppc_create_vcpu_debugfs(vcpu, id); > + } > return vcpu; > } > > -- > 1.7.0.4 > From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Graf Date: Tue, 20 Dec 2011 15:20:37 +0000 Subject: Re: [PATCH 07/28] kvm tools: Move 'kvm__recommended_cpus' to arch-specific code Message-Id: List-Id: References: <4EDD8E73.8040505@ozlabs.org> <1323159616.3882.7.camel@lappy> <4EDF04F4.40805@ozlabs.org> <1323239695.8489.25.camel@lappy> <4EDF138E.6040703@ozlabs.org> In-Reply-To: <4EDF138E.6040703@ozlabs.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Matt Evans Cc: Sasha Levin , kvm@vger.kernel.org, kvm-ppc@vger.kernel.org On 07.12.2011, at 08:19, Matt Evans 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. :) > > > Cheers, > > > Matt > > --- > Subject: [PATCH] KVM: PPC: Fix vcpu_create dereference before validity check. > > > Signed-off-by: Matt Evans Thanks, applied to kvm-ppc-next with an actual patch description added. Alex > --- > arch/powerpc/kvm/powerpc.c | 5 +++-- > 1 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c > index 084d1c5..7c7220c 100644 > --- a/arch/powerpc/kvm/powerpc.c > +++ b/arch/powerpc/kvm/powerpc.c > @@ -285,9 +285,10 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id) > { > struct kvm_vcpu *vcpu; > vcpu = kvmppc_core_vcpu_create(kvm, id); > - vcpu->arch.wqp = &vcpu->wq; > - if (!IS_ERR(vcpu)) > + if (!IS_ERR(vcpu)) { > + vcpu->arch.wqp = &vcpu->wq; > kvmppc_create_vcpu_debugfs(vcpu, id); > + } > return vcpu; > } > > -- > 1.7.0.4 >