Messages in this thread | | | Date | Wed, 2 Nov 2022 16:06:20 +0800 | Subject | Re: [PATCH v10 017/108] KVM: TDX: Refuse to unplug the last cpu on the package | From | Binbin Wu <> |
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On 2022/10/30 14:22, isaku.yamahata@intel.com wrote: > From: Isaku Yamahata <isaku.yamahata@intel.com> > > In order to reclaim TDX host key id, (i.e. when deleting guest TD), needs > to call TDH.PHYMEM.PAGE.WBINVD on all packages. If we have used TDX host > key id, refuse to offline the last online cpu. > > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> > --- > arch/x86/include/asm/kvm-x86-ops.h | 1 + > arch/x86/include/asm/kvm_host.h | 1 + > arch/x86/kvm/vmx/main.c | 1 + > arch/x86/kvm/vmx/tdx.c | 40 +++++++++++++++++++++++++++++- > arch/x86/kvm/vmx/x86_ops.h | 2 ++ > arch/x86/kvm/x86.c | 27 ++++++++++++-------- > 6 files changed, 61 insertions(+), 11 deletions(-) > > diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h > index 3a29a6b31ee8..0ceb8e58a6c0 100644 > --- a/arch/x86/include/asm/kvm-x86-ops.h > +++ b/arch/x86/include/asm/kvm-x86-ops.h > @@ -17,6 +17,7 @@ BUILD_BUG_ON(1) > KVM_X86_OP(hardware_enable) > KVM_X86_OP(hardware_disable) > KVM_X86_OP(hardware_unsetup) > +KVM_X86_OP_OPTIONAL_RET0(offline_cpu) > KVM_X86_OP(has_emulated_msr) > KVM_X86_OP(vcpu_after_set_cpuid) > KVM_X86_OP(is_vm_type_supported) > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index 2870155ce6fb..50b39d0071ff 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -1466,6 +1466,7 @@ struct kvm_x86_ops { > int (*hardware_enable)(void); > void (*hardware_disable)(void); > void (*hardware_unsetup)(void); > + int (*offline_cpu)(void); > bool (*has_emulated_msr)(struct kvm *kvm, u32 index); > void (*vcpu_after_set_cpuid)(struct kvm_vcpu *vcpu); > > diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c > index d01a946a18cf..0918d1e6d2f3 100644 > --- a/arch/x86/kvm/vmx/main.c > +++ b/arch/x86/kvm/vmx/main.c > @@ -67,6 +67,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = { > .name = "kvm_intel", > > .hardware_unsetup = vt_hardware_unsetup, > + .offline_cpu = tdx_offline_cpu, > .check_processor_compatibility = vmx_check_processor_compatibility, > > .hardware_enable = vmx_hardware_enable, > diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c > index ec88dde0d300..64229c3b3c5a 100644 > --- a/arch/x86/kvm/vmx/tdx.c > +++ b/arch/x86/kvm/vmx/tdx.c > @@ -42,6 +42,7 @@ static struct tdx_capabilities tdx_caps; > */ > static DEFINE_MUTEX(tdx_lock); > static struct mutex *tdx_mng_key_config_lock; > +static atomic_t nr_configured_hkid; > > static __always_inline hpa_t set_hkid_to_hpa(hpa_t pa, u16 hkid) > { > @@ -222,7 +223,8 @@ void tdx_mmu_release_hkid(struct kvm *kvm) > pr_err("tdh_mng_key_freeid failed. HKID %d is leaked.\n", > kvm_tdx->hkid); > return; > - } > + } else > + atomic_dec(&nr_configured_hkid); > > free_hkid: > tdx_hkid_free(kvm_tdx); > @@ -371,6 +373,8 @@ int tdx_vm_init(struct kvm *kvm) > if (ret) > break; > } > + if (!ret) > + atomic_inc(&nr_configured_hkid); > cpus_read_unlock(); > free_cpumask_var(packages); > if (ret) > @@ -514,3 +518,37 @@ void tdx_hardware_unsetup(void) > /* kfree accepts NULL. */ > kfree(tdx_mng_key_config_lock); > } > + > +int tdx_offline_cpu(void) > +{ > + int curr_cpu = smp_processor_id(); > + cpumask_var_t packages; > + int ret = 0; > + int i; > + > + if (!atomic_read(&nr_configured_hkid)) > + return 0; > + > + /* > + * To reclaim hkid, need to call TDH.PHYMEM.PAGE.WBINVD on all packages. > + * If this is the last online cpu on the package, refuse offline. > + */ > + if (!zalloc_cpumask_var(&packages, GFP_KERNEL)) > + return -ENOMEM; > + > + for_each_online_cpu(i) { > + if (i != curr_cpu) > + cpumask_set_cpu(topology_physical_package_id(i), packages); > + } > + if (!cpumask_test_cpu(topology_physical_package_id(curr_cpu), packages)) > + ret = -EBUSY; > + free_cpumask_var(packages); > + if (ret) > + /* > + * Because it's hard for human operator to understand the > + * reason, warn it. > + */ > + pr_warn("TDX requires all packages to have an online CPU. " > + "Delete all TDs in order to offline all CPUs of a package.\n"); > + return ret; > +} > diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h > index 95da978c9aa9..b2cb5786830a 100644 > --- a/arch/x86/kvm/vmx/x86_ops.h > +++ b/arch/x86/kvm/vmx/x86_ops.h > @@ -134,6 +134,7 @@ void vmx_setup_mce(struct kvm_vcpu *vcpu); > int __init tdx_hardware_setup(struct kvm_x86_ops *x86_ops); > bool tdx_is_vm_type_supported(unsigned long type); > void tdx_hardware_unsetup(void); > +int tdx_offline_cpu(void); > > int tdx_vm_init(struct kvm *kvm); > void tdx_mmu_release_hkid(struct kvm *kvm); > @@ -142,6 +143,7 @@ void tdx_vm_free(struct kvm *kvm); > static inline int tdx_hardware_setup(struct kvm_x86_ops *x86_ops) { return 0; } > static inline bool tdx_is_vm_type_supported(unsigned long type) { return false; } > static inline void tdx_hardware_unsetup(void) {} > +static inline int tdx_offline_cpu(void) { return 0; } > > static inline int tdx_vm_init(struct kvm *kvm) { return -EOPNOTSUPP; } > static inline void tdx_mmu_release_hkid(struct kvm *kvm) {} > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 4b22196cb12c..25c30c8c2d9b 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -12337,16 +12337,23 @@ int kvm_arch_online_cpu(unsigned int cpu, int usage_count) > > int kvm_arch_offline_cpu(unsigned int cpu, int usage_count) > { > - if (usage_count) { > - /* > - * arch callback kvm_arch_hardware_disable() assumes that > - * preemption is disabled for historical reason. Disable > - * preemption until all arch callbacks are fixed. > - */ > - preempt_disable(); > - hardware_disable(NULL); > - preempt_enable(); > - } > + int ret; > + > + if (!usage_count) > + return 0; > + > + ret = static_call(kvm_x86_offline_cpu)();
Use static_call_cond instead? Seems the new interface for x86 is only implemented for Intel.
> + if (ret) > + return ret; > + > + /* > + * arch callback kvm_arch_hardware_disable() assumes that preemption is > + * disabled for historical reason. Disable preemption until all arch > + * callbacks are fixed. > + */ > + preempt_disable(); > + hardware_disable(NULL); > + preempt_enable(); > return 0; > } >
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