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SubjectRe: [RFC PATCH v5 022/104] KVM: Add max_vcpus field in common 'struct kvm'
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On 3/4/22 20:48, isaku.yamahata@intel.com wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
>
> For TDX guests, the maximum number of vcpus needs to be specified when the
> TDX guest VM is initialized (creating the TDX data corresponding to TDX
> guest) before creating vcpu. It needs to record the maximum number of
> vcpus on VM creation (KVM_CREATE_VM) and return error if the number of
> vcpus exceeds it
>
> Because there is already max_vcpu member in arm64 struct kvm_arch, move it
> to common struct kvm and initialize it to KVM_MAX_VCPUS before
> kvm_arch_init_vm() instead of adding it to x86 struct kvm_arch.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> ---
> arch/arm64/include/asm/kvm_host.h | 3 ---
> arch/arm64/kvm/arm.c | 6 +++---
> arch/arm64/kvm/vgic/vgic-init.c | 6 +++---
> include/linux/kvm_host.h | 1 +
> virt/kvm/kvm_main.c | 3 ++-
> 5 files changed, 9 insertions(+), 10 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index 5bc01e62c08a..27249d634605 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -107,9 +107,6 @@ struct kvm_arch {
> /* VTCR_EL2 value for this VM */
> u64 vtcr;
>
> - /* The maximum number of vCPUs depends on the used GIC model */
> - int max_vcpus;
> -
> /* Interrupt controller */
> struct vgic_dist vgic;
>
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index ecc5958e27fe..defec2cd94bd 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -153,7 +153,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
> kvm_vgic_early_init(kvm);
>
> /* The maximum number of VCPUs is limited by the host's GIC model */
> - kvm->arch.max_vcpus = kvm_arm_default_max_vcpus();
> + kvm->max_vcpus = kvm_arm_default_max_vcpus();
>
> set_default_spectre(kvm);
>
> @@ -229,7 +229,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
> case KVM_CAP_MAX_VCPUS:
> case KVM_CAP_MAX_VCPU_ID:
> if (kvm)
> - r = kvm->arch.max_vcpus;
> + r = kvm->max_vcpus;
> else
> r = kvm_arm_default_max_vcpus();
> break;
> @@ -305,7 +305,7 @@ int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id)
> if (irqchip_in_kernel(kvm) && vgic_initialized(kvm))
> return -EBUSY;
>
> - if (id >= kvm->arch.max_vcpus)
> + if (id >= kvm->max_vcpus)
> return -EINVAL;
>
> return 0;
> diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c
> index fc00304fe7d8..77feafd5c0e3 100644
> --- a/arch/arm64/kvm/vgic/vgic-init.c
> +++ b/arch/arm64/kvm/vgic/vgic-init.c
> @@ -98,11 +98,11 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
> ret = 0;
>
> if (type == KVM_DEV_TYPE_ARM_VGIC_V2)
> - kvm->arch.max_vcpus = VGIC_V2_MAX_CPUS;
> + kvm->max_vcpus = VGIC_V2_MAX_CPUS;
> else
> - kvm->arch.max_vcpus = VGIC_V3_MAX_CPUS;
> + kvm->max_vcpus = VGIC_V3_MAX_CPUS;
>
> - if (atomic_read(&kvm->online_vcpus) > kvm->arch.max_vcpus) {
> + if (atomic_read(&kvm->online_vcpus) > kvm->max_vcpus) {
> ret = -E2BIG;
> goto out_unlock;
> }
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index f11039944c08..a56044a31bc6 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -715,6 +715,7 @@ struct kvm {
> * and is accessed atomically.
> */
> atomic_t online_vcpus;
> + int max_vcpus;
> int created_vcpus;
> int last_boosted_vcpu;
> struct list_head vm_list;
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 52f72a366beb..3adee9c6b370 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -1075,6 +1075,7 @@ static struct kvm *kvm_create_vm(unsigned long type)
> spin_lock_init(&kvm->gpc_lock);
>
> INIT_LIST_HEAD(&kvm->devices);
> + kvm->max_vcpus = KVM_MAX_VCPUS;
>
> BUILD_BUG_ON(KVM_MEM_SLOTS_NUM > SHRT_MAX);
>
> @@ -3718,7 +3719,7 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
> return -EINVAL;
>
> mutex_lock(&kvm->lock);
> - if (kvm->created_vcpus == KVM_MAX_VCPUS) {
> + if (kvm->created_vcpus >= kvm->max_vcpus) {
> mutex_unlock(&kvm->lock);
> return -EINVAL;
> }

Queued this one already, thanks.

Paolo

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