On 03.09.21 16:41, Marc Zyngier wrote: > On Fri, 03 Sep 2021 14:08:06 +0100, > Juergen Gross wrote: >> >> Prepare support of very large vcpu numbers per guest by moving the >> vcpu pointer array out of struct kvm. >> >> Signed-off-by: Juergen Gross >> --- >> V2: >> - rebase to new kvm_arch_free_vm() implementation >> --- >> arch/arm64/kvm/arm.c | 21 +++++++++++++++++++-- >> arch/x86/include/asm/kvm_host.h | 5 +---- >> arch/x86/kvm/x86.c | 18 ++++++++++++++++++ >> include/linux/kvm_host.h | 17 +++++++++++++++-- >> 4 files changed, 53 insertions(+), 8 deletions(-) >> >> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c >> index 38fff5963d9f..8bb5caeba007 100644 >> --- a/arch/arm64/kvm/arm.c >> +++ b/arch/arm64/kvm/arm.c >> @@ -293,10 +293,27 @@ long kvm_arch_dev_ioctl(struct file *filp, >> >> struct kvm *kvm_arch_alloc_vm(void) >> { >> + struct kvm *kvm; >> + >> + if (!has_vhe()) >> + kvm = kzalloc(sizeof(struct kvm), GFP_KERNEL); >> + else >> + kvm = vzalloc(sizeof(struct kvm)); >> + >> + if (!kvm) >> + return NULL; >> + >> if (!has_vhe()) >> - return kzalloc(sizeof(struct kvm), GFP_KERNEL); >> + kvm->vcpus = kcalloc(KVM_MAX_VCPUS, sizeof(void *), GFP_KERNEL); >> + else >> + kvm->vcpus = vzalloc(KVM_MAX_VCPUS * sizeof(void *)); >> + >> + if (!kvm->vcpus) { >> + kvm_arch_free_vm(kvm); >> + kvm = NULL; >> + } >> >> - return vzalloc(sizeof(struct kvm)); >> + return kvm; >> } >> >> int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id) >> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h >> index f16fadfc030a..6c28d0800208 100644 >> --- a/arch/x86/include/asm/kvm_host.h >> +++ b/arch/x86/include/asm/kvm_host.h >> @@ -1517,10 +1517,7 @@ static inline void kvm_ops_static_call_update(void) >> } >> >> #define __KVM_HAVE_ARCH_VM_ALLOC >> -static inline struct kvm *kvm_arch_alloc_vm(void) >> -{ >> - return __vmalloc(kvm_x86_ops.vm_size, GFP_KERNEL_ACCOUNT | __GFP_ZERO); >> -} >> +struct kvm *kvm_arch_alloc_vm(void); >> >> #define __KVM_HAVE_ARCH_VM_FREE >> void kvm_arch_free_vm(struct kvm *kvm); >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >> index cc552763f0e4..ff142b6dd00c 100644 >> --- a/arch/x86/kvm/x86.c >> +++ b/arch/x86/kvm/x86.c >> @@ -11126,6 +11126,24 @@ void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) >> static_call(kvm_x86_sched_in)(vcpu, cpu); >> } >> >> +struct kvm *kvm_arch_alloc_vm(void) >> +{ >> + struct kvm *kvm; >> + >> + kvm = __vmalloc(kvm_x86_ops.vm_size, GFP_KERNEL_ACCOUNT | __GFP_ZERO); >> + if (!kvm) >> + return NULL; >> + >> + kvm->vcpus = __vmalloc(KVM_MAX_VCPUS * sizeof(void *), >> + GFP_KERNEL_ACCOUNT | __GFP_ZERO); >> + if (!kvm->vcpus) { >> + vfree(kvm); >> + kvm = NULL; >> + } >> + >> + return kvm; >> +} >> + >> void kvm_arch_free_vm(struct kvm *kvm) >> { >> kfree(to_kvm_hv(kvm)->hv_pa_pg); >> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h >> index d75e9c2a00b1..9e2a5f1c6f54 100644 >> --- a/include/linux/kvm_host.h >> +++ b/include/linux/kvm_host.h >> @@ -536,7 +536,7 @@ struct kvm { >> struct mutex slots_arch_lock; >> struct mm_struct *mm; /* userspace tied to this vm */ >> struct kvm_memslots __rcu *memslots[KVM_ADDRESS_SPACE_NUM]; >> - struct kvm_vcpu *vcpus[KVM_MAX_VCPUS]; >> + struct kvm_vcpu **vcpus; > > At this stage, I really wonder why we are not using an xarray instead. > > I wrote this [1] a while ago, and nothing caught fire. It was also a > net deletion of code... Indeed, I'd prefer that solution! Are you fine with me swapping my patch with yours in the series? Juergen