From nobody Fri Dec 19 14:08:14 2025 Received: from mail-pf1-f201.google.com (mail-pf1-f201.google.com [209.85.210.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E62842609DC for ; Sat, 6 Dec 2025 01:11:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764983479; cv=none; b=CvIM/2/oESINAAfa41+jjXMg57M/y61MMap9EltSWyTAu6ZiY+hkBayMCODFIZDD9qkrPamPtBN6gSvMum3CEcoqx8yEwYaV30eie7FKE16QVLN8XrQbROHuDkipasDOvdhY4ylzWn9Jc+CVbfIco7HECmzy4TkPHtipRAovdJ8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764983479; c=relaxed/simple; bh=KQpJgpfMzgTc3IeJzO8g2QU2GWsQrVFHCetE2jQYut8=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=asoULZ8zPRrH747FSfsbi3lG5KrpE4myo2u0EzeS5QG/pMnvT7h7SZxiCk/JpyQ/gfQZu/PBazGhQ352aoTrJhUYqbIu1BFA/TzcOgH7XAHtGHvHbTlvV+dTLkR++Gdpz4xm0I789jRgqUmwjcKQP6Uq43wzeWDIWiSFxL8r4qg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=RsusmDd0; arc=none smtp.client-ip=209.85.210.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="RsusmDd0" Received: by mail-pf1-f201.google.com with SMTP id d2e1a72fcca58-7b8a12f0cb4so2939756b3a.3 for ; Fri, 05 Dec 2025 17:11:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1764983476; x=1765588276; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=JojZY3uhd5k3hZOQJMhjmwW30PBC8/7wDoPAbDrCEls=; b=RsusmDd0jNs193QTuzMQnjHBHF+7bLfJP7s333Av5KQbrEXg01ty+CW3caEForlHaa KMkFhZkEki9PojYefqZoQKBgYY6W8AZjZ5KJbrqJoxzh+ncZkNZA5JnCrHXMeNJzauyz TS9vuqpnK3Famayi0BhpGkjkfEKT2bAs8SU3/6/51cxQRk/XO8jiQJiqBJ5ydm5p6gab GyDosSleqqes5Z7861n+gUS4LEsxoa3OE2uG0kgMgdj5plD9KZv7CyXw5QlXC91DolCQ AGniVPc4Oz927q/8Xm1sgWhDvcUPzZyWN6lRLez5A5pV4sC/wiZLlrFgqiw8VSxMEOzp DQlA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1764983476; x=1765588276; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=JojZY3uhd5k3hZOQJMhjmwW30PBC8/7wDoPAbDrCEls=; b=wcf/h9pN4rpeaE/f3edQpT7KYag58DmCozV5Zv6TVlXhKvB9Ri+BwVHXsX3FFzTq6M 5EGsg1aAaxGyo1ouPQnzP5CTy3sEhsGNOB+rNAJ4PnOJjhSqkz6W0X5a6M9drR4XO6hq cvzKKn2I4+Uqtm5a5QB3Zjhxqq+KYs8kFJTdFOj0dTfC1gG6zRYGW8qaQLI01NJaccDe 77jKMlDqO+sy8aHNw4eWlidYGqzhxiFgbwlftsUf9TERXnrEp5JQcjnazcwHdZLqSlJW HzHCmFashw5rpfhN7IvEgQiTUZm1BZE5+wFhBMNGf3PEo9twEQ2VwPB2Ma6lyS/VsCp3 EwYQ== X-Gm-Message-State: AOJu0Yxah+D+FcT/uvaifHMuGBo/yIF0sFGbb93H1BacathpSCiQgfya abXc8G1Hf4UVjEQaPQkcoRv0EhfngAtA3OoqekuCcuostDq3ci86tY3ETQlvyKsHO3yFR6aPUCJ 8LBr/QA== X-Google-Smtp-Source: AGHT+IEiragae11BDcwJ25pWhkPQUadOVyTO8WpDoz2naWj0OyOQpfwATE9mA9Trjd4vlWLzMj3ulCcvo0M= X-Received: from pfmm5.prod.google.com ([2002:a05:6a00:2485:b0:7cf:2dad:ff87]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:94f1:b0:7e8:43f5:bd54 with SMTP id d2e1a72fcca58-7e8c5048a31mr914583b3a.64.1764983476061; Fri, 05 Dec 2025 17:11:16 -0800 (PST) Reply-To: Sean Christopherson Date: Fri, 5 Dec 2025 17:10:52 -0800 In-Reply-To: <20251206011054.494190-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20251206011054.494190-1-seanjc@google.com> X-Mailer: git-send-email 2.52.0.223.gf5cc29aaa4-goog Message-ID: <20251206011054.494190-6-seanjc@google.com> Subject: [PATCH v2 5/7] x86/virt/tdx: KVM: Consolidate TDX CPU hotplug handling From: Sean Christopherson To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Kiryl Shutsemau , Sean Christopherson , Paolo Bonzini Cc: linux-kernel@vger.kernel.org, linux-coco@lists.linux.dev, kvm@vger.kernel.org, Chao Gao , Dan Williams Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Chao Gao The core kernel registers a CPU hotplug callback to do VMX and TDX init and deinit while KVM registers a separate CPU offline callback to block offlining the last online CPU in a socket. Splitting TDX-related CPU hotplug handling across two components is odd and adds unnecessary complexity. Consolidate TDX-related CPU hotplug handling by integrating KVM's tdx_offline_cpu() to the one in the core kernel. Also move nr_configured_hkid to the core kernel because tdx_offline_cpu() references it. Since HKID allocation and free are handled in the core kernel, it's more natural to track used HKIDs there. Signed-off-by: Chao Gao Signed-off-by: Sean Christopherson Reviewed-by: Dan Williams --- arch/x86/kvm/vmx/tdx.c | 67 +------------------------------------ arch/x86/virt/vmx/tdx/tdx.c | 49 +++++++++++++++++++++++++-- 2 files changed, 47 insertions(+), 69 deletions(-) diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index d0161dc3d184..d9dd6070baa0 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -59,8 +59,6 @@ module_param_named(tdx, enable_tdx, bool, 0444); #define TDX_SHARED_BIT_PWL_5 gpa_to_gfn(BIT_ULL(51)) #define TDX_SHARED_BIT_PWL_4 gpa_to_gfn(BIT_ULL(47)) =20 -static enum cpuhp_state tdx_cpuhp_state __ro_after_init; - static const struct tdx_sys_info *tdx_sysinfo; =20 void tdh_vp_rd_failed(struct vcpu_tdx *tdx, char *uclass, u32 field, u64 e= rr) @@ -219,8 +217,6 @@ static int init_kvm_tdx_caps(const struct tdx_sys_info_= td_conf *td_conf, */ static DEFINE_MUTEX(tdx_lock); =20 -static atomic_t nr_configured_hkid; - static bool tdx_operand_busy(u64 err) { return (err & TDX_SEAMCALL_STATUS_MASK) =3D=3D TDX_OPERAND_BUSY; @@ -268,7 +264,6 @@ static inline void tdx_hkid_free(struct kvm_tdx *kvm_td= x) { tdx_guest_keyid_free(kvm_tdx->hkid); kvm_tdx->hkid =3D -1; - atomic_dec(&nr_configured_hkid); misc_cg_uncharge(MISC_CG_RES_TDX, kvm_tdx->misc_cg, 1); put_misc_cg(kvm_tdx->misc_cg); kvm_tdx->misc_cg =3D NULL; @@ -2399,8 +2394,6 @@ static int __tdx_td_init(struct kvm *kvm, struct td_p= arams *td_params, =20 ret =3D -ENOMEM; =20 - atomic_inc(&nr_configured_hkid); - tdr_page =3D alloc_page(GFP_KERNEL); if (!tdr_page) goto free_hkid; @@ -3302,51 +3295,10 @@ int tdx_gmem_max_mapping_level(struct kvm *kvm, kvm= _pfn_t pfn, bool is_private) return PG_LEVEL_4K; } =20 -static int tdx_online_cpu(unsigned int cpu) -{ - return 0; -} - -static int tdx_offline_cpu(unsigned int cpu) -{ - int i; - - /* No TD is running. Allow any cpu to be offline. */ - if (!atomic_read(&nr_configured_hkid)) - return 0; - - /* - * In order to reclaim TDX HKID, (i.e. when deleting guest TD), need to - * call TDH.PHYMEM.PAGE.WBINVD on all packages to program all memory - * controller with pconfig. If we have active TDX HKID, refuse to - * offline the last online cpu. - */ - for_each_online_cpu(i) { - /* - * Found another online cpu on the same package. - * Allow to offline. - */ - if (i !=3D cpu && topology_physical_package_id(i) =3D=3D - topology_physical_package_id(cpu)) - return 0; - } - - /* - * This is the last cpu of this package. Don't offline it. - * - * Because it's hard for human operator to understand the - * reason, warn it. - */ -#define MSG_ALLPKG_ONLINE \ - "TDX requires all packages to have an online CPU. Delete all TDs in order= to offline all CPUs of a package.\n" - pr_warn_ratelimited(MSG_ALLPKG_ONLINE); - return -EBUSY; -} - static int __init __tdx_bringup(void) { const struct tdx_sys_info_td_conf *td_conf; - int r, i; + int i; =20 for (i =3D 0; i < ARRAY_SIZE(tdx_uret_msrs); i++) { /* @@ -3414,23 +3366,7 @@ static int __init __tdx_bringup(void) if (misc_cg_set_capacity(MISC_CG_RES_TDX, tdx_get_nr_guest_keyids())) return -EINVAL; =20 - /* - * TDX-specific cpuhp callback to disallow offlining the last CPU in a - * packing while KVM is running one or more TDs. Reclaiming HKIDs - * requires doing PAGE.WBINVD on every package, i.e. offlining all CPUs - * of a package would prevent reclaiming the HKID. - */ - r =3D cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "kvm/cpu/tdx:online", - tdx_online_cpu, tdx_offline_cpu); - if (r < 0) - goto err_cpuhup; - - tdx_cpuhp_state =3D r; return 0; - -err_cpuhup: - misc_cg_set_capacity(MISC_CG_RES_TDX, 0); - return r; } =20 int __init tdx_bringup(void) @@ -3486,7 +3422,6 @@ void tdx_cleanup(void) return; =20 misc_cg_set_capacity(MISC_CG_RES_TDX, 0); - cpuhp_remove_state(tdx_cpuhp_state); } =20 void __init tdx_hardware_setup(void) diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c index d49645797fe4..5cf008bffa94 100644 --- a/arch/x86/virt/vmx/tdx/tdx.c +++ b/arch/x86/virt/vmx/tdx/tdx.c @@ -58,6 +58,8 @@ static LIST_HEAD(tdx_memlist); static struct tdx_sys_info tdx_sysinfo __ro_after_init; static bool tdx_module_initialized __ro_after_init; =20 +static atomic_t nr_configured_hkid; + typedef void (*sc_err_func_t)(u64 fn, u64 err, struct tdx_module_args *arg= s); =20 static inline void seamcall_err(u64 fn, u64 err, struct tdx_module_args *a= rgs) @@ -190,6 +192,40 @@ static int tdx_online_cpu(unsigned int cpu) =20 static int tdx_offline_cpu(unsigned int cpu) { + int i; + + /* No TD is running. Allow any cpu to be offline. */ + if (!atomic_read(&nr_configured_hkid)) + goto done; + + /* + * In order to reclaim TDX HKID, (i.e. when deleting guest TD), need to + * call TDH.PHYMEM.PAGE.WBINVD on all packages to program all memory + * controller with pconfig. If we have active TDX HKID, refuse to + * offline the last online cpu. + */ + for_each_online_cpu(i) { + /* + * Found another online cpu on the same package. + * Allow to offline. + */ + if (i !=3D cpu && topology_physical_package_id(i) =3D=3D + topology_physical_package_id(cpu)) + goto done; + } + + /* + * This is the last cpu of this package. Don't offline it. + * + * Because it's hard for human operator to understand the + * reason, warn it. + */ +#define MSG_ALLPKG_ONLINE \ + "TDX requires all packages to have an online CPU. Delete all TDs in order= to offline all CPUs of a package.\n" + pr_warn_ratelimited(MSG_ALLPKG_ONLINE); + return -EBUSY; + +done: x86_virt_put_cpu(X86_FEATURE_VMX); return 0; } @@ -1506,15 +1542,22 @@ EXPORT_SYMBOL_GPL(tdx_get_nr_guest_keyids); =20 int tdx_guest_keyid_alloc(void) { - return ida_alloc_range(&tdx_guest_keyid_pool, tdx_guest_keyid_start, - tdx_guest_keyid_start + tdx_nr_guest_keyids - 1, - GFP_KERNEL); + int ret; + + ret =3D ida_alloc_range(&tdx_guest_keyid_pool, tdx_guest_keyid_start, + tdx_guest_keyid_start + tdx_nr_guest_keyids - 1, + GFP_KERNEL); + if (ret >=3D 0) + atomic_inc(&nr_configured_hkid); + + return ret; } EXPORT_SYMBOL_GPL(tdx_guest_keyid_alloc); =20 void tdx_guest_keyid_free(unsigned int keyid) { ida_free(&tdx_guest_keyid_pool, keyid); + atomic_dec(&nr_configured_hkid); } EXPORT_SYMBOL_GPL(tdx_guest_keyid_free); =20 --=20 2.52.0.223.gf5cc29aaa4-goog