From mboxrd@z Thu Jan 1 00:00:00 1970 From: christoffer.dall@linaro.org (Christoffer Dall) Date: Mon, 3 Nov 2014 21:06:00 +0100 Subject: [PATCH v3 09/19] arm/arm64: KVM: make the maximum number of vCPUs a per-VM value In-Reply-To: <1414776414-13426-10-git-send-email-andre.przywara@arm.com> References: <1414776414-13426-1-git-send-email-andre.przywara@arm.com> <1414776414-13426-10-git-send-email-andre.przywara@arm.com> Message-ID: <20141103200600.GL16132@cbox> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Oct 31, 2014 at 05:26:44PM +0000, Andre Przywara wrote: > Currently the maximum number of vCPUs supported is a global value > limited by the used GIC model. GICv3 will lift this limit, but we > still need to observe it for guests using GICv2. > So the maximum number of vCPUs is per-VM value, depending on the > GIC model the guest uses. > Store and check the value in struct kvm_arch, but keep it down to > 8 for now. > > Signed-off-by: Andre Przywara > --- > arch/arm/include/asm/kvm_host.h | 1 + > arch/arm/kvm/arm.c | 6 ++++++ > arch/arm64/include/asm/kvm_host.h | 3 +++ > virt/kvm/arm/vgic-v2.c | 7 +++++++ > virt/kvm/arm/vgic-v3.c | 8 ++++++++ > 5 files changed, 25 insertions(+) > > diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h > index b443dfe..7969e6e 100644 > --- a/arch/arm/include/asm/kvm_host.h > +++ b/arch/arm/include/asm/kvm_host.h > @@ -68,6 +68,7 @@ struct kvm_arch { > > /* Interrupt controller */ > struct vgic_dist vgic; > + int max_vcpus; > }; > > #define KVM_NR_MEM_OBJS 40 > diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c > index 60c7997..ac0aa7f 100644 > --- a/arch/arm/kvm/arm.c > +++ b/arch/arm/kvm/arm.c > @@ -131,6 +131,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) > > /* Mark the initial VMID generation invalid */ > kvm->arch.vmid_gen = 0; > + kvm->arch.max_vcpus = CONFIG_KVM_ARM_MAX_VCPUS; > > return ret; > out_free_stage2_pgd: > @@ -213,6 +214,11 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id) > int err; > struct kvm_vcpu *vcpu; > > + if (id >= kvm->arch.max_vcpus) { > + err = -EINVAL; > + goto out; > + } > + > vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL); > if (!vcpu) { > err = -ENOMEM; > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index 286bb61..f9e130d 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -59,6 +59,9 @@ struct kvm_arch { > /* VTTBR value associated with above pgd and vmid */ > u64 vttbr; > > + /* The maximum number of vCPUs depends on the used GIC model */ > + int max_vcpus; > + > /* Interrupt controller */ > struct vgic_dist vgic; > > diff --git a/virt/kvm/arm/vgic-v2.c b/virt/kvm/arm/vgic-v2.c > index 417ecaa..c92ac33 100644 > --- a/virt/kvm/arm/vgic-v2.c > +++ b/virt/kvm/arm/vgic-v2.c > @@ -159,11 +159,18 @@ static struct vgic_params vgic_v2_params; > static bool vgic_v2_init_emul(struct kvm *kvm, int type) > { > struct vgic_vm_ops *vm_ops = &kvm->arch.vgic.vm_ops; > + int nr_vcpus; > > switch (type) { > case KVM_DEV_TYPE_ARM_VGIC_V2: > + nr_vcpus = atomic_read(&kvm->online_vcpus); > + if (nr_vcpus > 8) { > + pr_warn_ratelimited("VGICv2 only supports up to 8 vCPUs\n"); > + return false; > + } > vm_ops->get_lr = vgic_v2_get_lr; > vm_ops->set_lr = vgic_v2_set_lr; > + kvm->arch.max_vcpus = 8; > return true; > } > > diff --git a/virt/kvm/arm/vgic-v3.c b/virt/kvm/arm/vgic-v3.c > index 6825c71..fc4d628 100644 > --- a/virt/kvm/arm/vgic-v3.c > +++ b/virt/kvm/arm/vgic-v3.c > @@ -171,11 +171,19 @@ static const struct vgic_ops vgic_v3_ops = { > static bool vgic_v3_init_emul_compat(struct kvm *kvm, int type) > { > struct vgic_vm_ops *vm_ops = &kvm->arch.vgic.vm_ops; > + int nr_vcpus; > > switch (type) { > case KVM_DEV_TYPE_ARM_VGIC_V2: > + nr_vcpus = atomic_read(&kvm->online_vcpus); > + if (nr_vcpus > 8) { > + pr_warn_ratelimited("VGICv2 supports only up to 8 vCPUs\n"); > + return false; > + } > + > vm_ops->get_lr = vgic_v3_get_lr; > vm_ops->set_lr = vgic_v3_set_lr; > + kvm->arch.max_vcpus = 8; This is exactly the same code as above, and it feels a bit weird to have this code be dependent on which host gic you have, unless you plan on supporting a frankenvgicv2 in the guest with more than 8 vcpus? Don't we have some common place for gicv2 emulation where we can stick this, set the max_vcpus (perhaps using a #define) and then compare the nr_vcpus to the max_vcpus? > return true; > } > return false; > -- > 1.7.9.5 > Thanks, -Christoffer