| Message ID | 4EDF138E.6040703@ozlabs.org |
|---|---|
| State | New, archived |
| Headers | show |
On 07.12.2011, at 08:19, Matt Evans <matt@ozlabs.org> 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 :). I suppose this is stable material? Alex > -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 07/12/11 18:24, Alexander Graf wrote: > > On 07.12.2011, at 08:19, Matt Evans <matt@ozlabs.org> 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 <matt@ozlabs.org> ). I suppose no one's seen a vcpu fail to be created, yet. Thanks, Matt -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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 <matt@ozlabs.org> 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 > -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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; }