From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6FB3DC4332F for ; Wed, 2 Nov 2022 08:06:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229949AbiKBIGa (ORCPT ); Wed, 2 Nov 2022 04:06:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40284 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230335AbiKBIG1 (ORCPT ); Wed, 2 Nov 2022 04:06:27 -0400 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 65637275E2; Wed, 2 Nov 2022 01:06:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1667376385; x=1698912385; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=x7lpqK2HGRRRUovKsHDPJSVlmxxxInIp+kFv4G/OMtY=; b=dY7SKXy7Les/Q9mnGXLPOSdSQhsErYEVKIADv6mWjKh7UzEU1oar5AHa yrD/fbrX48/1ta1XwpnZ3nOHzDoHkKghNpG1gojE0D9ydFVFFKhu+gLvQ /topj3J7Lnynxjx33CRI8z1N93gk0Zy3cfVzTQ81l8eihgMH7vK9Zdw52 YOj4hAUiiswmAjtiTeaEmVxxp5vDyScxLLm2xulKfwloJUIXztkkBQvGK IuFqMf8hkWWchgM9jQpN/siey26ppjm3oK9784pmyra/+oyiK5jL1UqjK 2wB1agBIL6YHpOqGueWvxZ0kWcqXWSFUM4f+9nqdrWy4xdDYUunM/y2TS A==; X-IronPort-AV: E=McAfee;i="6500,9779,10518"; a="289056823" X-IronPort-AV: E=Sophos;i="5.95,232,1661842800"; d="scan'208";a="289056823" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Nov 2022 01:06:25 -0700 X-IronPort-AV: E=McAfee;i="6500,9779,10518"; a="697714153" X-IronPort-AV: E=Sophos;i="5.95,232,1661842800"; d="scan'208";a="697714153" Received: from binbinwu-mobl.ccr.corp.intel.com (HELO [10.255.28.60]) ([10.255.28.60]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Nov 2022 01:06:22 -0700 Message-ID: <5bb42920-cd17-e235-bfe0-ba05f1e2b5bc@linux.intel.com> Date: Wed, 2 Nov 2022 16:06:20 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.4.0 Subject: Re: [PATCH v10 017/108] KVM: TDX: Refuse to unplug the last cpu on the package To: isaku.yamahata@intel.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: isaku.yamahata@gmail.com, Paolo Bonzini , erdemaktas@google.com, Sean Christopherson , Sagi Shahar , David Matlack References: From: Binbin Wu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/10/30 14:22, isaku.yamahata@intel.com wrote: > From: Isaku Yamahata > > 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 > --- > 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; > } >