From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f202.google.com (mail-pl1-f202.google.com [209.85.214.202]) (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 CAC1D2D7397 for ; Sat, 14 Feb 2026 01:27:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771032452; cv=none; b=IlkAFSSFNrmx/OYDQE/hH1unIZtlJaQ/gljRi79FUUSCYncTmk3x16k67UsudeOSe6xTDksGOH1EUWBDZmDqKwoyMTooDL68DGfQHp0NfpMfJQsccCo0SkU2LQoruipX//X0nJuLOQ9rbp6PQo18iWqk+Yt8wx4S+vvVL37zxK0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771032452; c=relaxed/simple; bh=E6Q5/+hh3nilZrpijZlxvvvkiid5ytZMA5bWglZIuIs=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=cQbzhWE+T/FLpv407BSvTJczpiiArTCrgF5mN19S6r94KISsy9F9+3DR7iwkRB8Y+NdvbcyGhzMSL7UugNvsU0LU6Xbqwdiml9V0tzP4y83FaPz6GvKycygT+09B/7KF5UiSPSzqLozii7qFOLu2BCfA9DnvD4RRqJ+WcvyJ+UQ= 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=EmD06Csy; arc=none smtp.client-ip=209.85.214.202 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="EmD06Csy" Received: by mail-pl1-f202.google.com with SMTP id d9443c01a7336-2aae146bab0so19379315ad.0 for ; Fri, 13 Feb 2026 17:27:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1771032449; x=1771637249; darn=lists.linux.dev; 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=f9/W8zXMCwCxOnxdB4EBaLa8j2TODn+O9pqKnu48UGU=; b=EmD06CsycoKUvXaODxSuTsyfB9wHJkC2CfRbUClem8JdKQLtaV9qa+oB8nbGj2YM3u t+3XE9FZMEzacRITO4Okwx/Xe4F1zXRphgfP0m65p3+cjkdAnH5SGEJArShMydCU9jxL Iv4Ztutd7oyOMVW7Jh2np44vyQQq+V77PRMBBMiwmAMJ+7nEKm4SQjj5VHFxLrMd+vCX QGeKU1kYmxZjcI5K1HuZySnh9gTtW9hNU+Jr9xUPxTxrOQGS/PinCCeKHINTfHLx3XHL VfFUA/bF3F01nkZ1jo9cyvrGtUoGVC7wmFuMkvrWxkN9/xGY1nR6L1Qfu7ciCFBcJ4II Bx+Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1771032449; x=1771637249; 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=f9/W8zXMCwCxOnxdB4EBaLa8j2TODn+O9pqKnu48UGU=; b=HqI6258FkgfR9p+PdFPor6KGfoZOnLnrPwy1ltlSnU1cZZLOd1Sut3/VP8S4LORpuG 6SAw5T3Y/fZLnvgfLMQzp6pj4urOXNo1T0FNcyhAdyRl2/8tEFIZOiOzupO6FRbHqNG4 s7v0uESsq2kGtbYmZTH+/G1gfKcUfm4XXHJbZUwaectvj+DuyNowxqAN5a5H+FbxfJSV 2I5emboxEmRuEmriL8RzcbSIanapZ16u1YCYjo/Fm4RN+kY3e935nH5xSI7DniMt8T7w e44G560GktqjtEO9PMNLEPDX5X0x1QAjGMPbcl1jkKMfAiy5Wr+NTV4JeVx9Ko/hG/7a r3yQ== X-Forwarded-Encrypted: i=1; AJvYcCUpjNTImmy0Hup5+FvzNRtCQ4zEJl493382BMS3MpTYL69KI2IuTN0jhdF8VW3awVumvN9E9my8qMMT@lists.linux.dev X-Gm-Message-State: AOJu0YxSDv0gpz9tjlijlFuXS576gP+TC8KCOpCcaRxpqG/pLh+F/XCE x6QR18sndvjCUfY+/LDvvCcpANElU+wRg8QnX8hXBYC/GMaG2AMWccLv/mPuPTeN+upOkjn3KYQ Nzzm87w== X-Received: from plmk2.prod.google.com ([2002:a17:903:1802:b0:2a4:2817:d023]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:cccd:b0:2a7:80bf:3131 with SMTP id d9443c01a7336-2ab5062d628mr31972075ad.58.1771032449020; Fri, 13 Feb 2026 17:27:29 -0800 (PST) Reply-To: Sean Christopherson Date: Fri, 13 Feb 2026 17:26:59 -0800 In-Reply-To: <20260214012702.2368778-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260214012702.2368778-1-seanjc@google.com> X-Mailer: git-send-email 2.53.0.310.g728cabbaf7-goog Message-ID: <20260214012702.2368778-14-seanjc@google.com> Subject: [PATCH v3 13/16] 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 , Peter Zijlstra , Arnaldo Carvalho de Melo , Namhyung Kim , Sean Christopherson , Paolo Bonzini Cc: linux-kernel@vger.kernel.org, linux-coco@lists.linux.dev, kvm@vger.kernel.org, linux-perf-users@vger.kernel.org, Chao Gao , Xu Yilun , Dan Williams 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. Reviewed-by: Dan Williams Signed-off-by: Chao Gao Signed-off-by: Sean Christopherson --- 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 0ac01c119336..fea3dfc7ac8b 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)) -static enum cpuhp_state tdx_cpuhp_state __ro_after_init; - static const struct tdx_sys_info *tdx_sysinfo; void tdh_vp_rd_failed(struct vcpu_tdx *tdx, char *uclass, u32 field, u64 err) @@ -219,8 +217,6 @@ static int init_kvm_tdx_caps(const struct tdx_sys_info_td_conf *td_conf, */ static DEFINE_MUTEX(tdx_lock); -static atomic_t nr_configured_hkid; - static bool tdx_operand_busy(u64 err) { return (err & TDX_SEAMCALL_STATUS_MASK) == TDX_OPERAND_BUSY; @@ -268,7 +264,6 @@ static inline void tdx_hkid_free(struct kvm_tdx *kvm_tdx) { tdx_guest_keyid_free(kvm_tdx->hkid); kvm_tdx->hkid = -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 = NULL; @@ -2399,8 +2394,6 @@ static int __tdx_td_init(struct kvm *kvm, struct td_params *td_params, ret = -ENOMEM; - atomic_inc(&nr_configured_hkid); - tdr_page = alloc_page(GFP_KERNEL); if (!tdr_page) goto free_hkid; @@ -3292,51 +3285,10 @@ int tdx_gmem_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn, bool is_private) return PG_LEVEL_4K; } -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 != cpu && topology_physical_package_id(i) == - 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; for (i = 0; i < ARRAY_SIZE(tdx_uret_msrs); i++) { /* @@ -3404,23 +3356,7 @@ static int __init __tdx_bringup(void) if (misc_cg_set_capacity(MISC_CG_RES_TDX, tdx_get_nr_guest_keyids())) return -EINVAL; - /* - * 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 = 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 = r; return 0; - -err_cpuhup: - misc_cg_set_capacity(MISC_CG_RES_TDX, 0); - return r; } int __init tdx_bringup(void) @@ -3488,7 +3424,6 @@ void tdx_cleanup(void) return; misc_cg_set_capacity(MISC_CG_RES_TDX, 0); - cpuhp_remove_state(tdx_cpuhp_state); } 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 05d634caa4e8..ddbab87d2467 100644 --- a/arch/x86/virt/vmx/tdx/tdx.c +++ b/arch/x86/virt/vmx/tdx/tdx.c @@ -59,6 +59,8 @@ static LIST_HEAD(tdx_memlist); static struct tdx_sys_info tdx_sysinfo __ro_after_init; static bool tdx_module_initialized __ro_after_init; +static atomic_t nr_configured_hkid; + typedef void (*sc_err_func_t)(u64 fn, u64 err, struct tdx_module_args *args); static inline void seamcall_err(u64 fn, u64 err, struct tdx_module_args *args) @@ -189,6 +191,40 @@ static int tdx_online_cpu(unsigned int cpu) 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 != cpu && topology_physical_package_id(i) == + 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_ref(X86_FEATURE_VMX); return 0; } @@ -1509,15 +1545,22 @@ EXPORT_SYMBOL_FOR_KVM(tdx_get_nr_guest_keyids); 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 = ida_alloc_range(&tdx_guest_keyid_pool, tdx_guest_keyid_start, + tdx_guest_keyid_start + tdx_nr_guest_keyids - 1, + GFP_KERNEL); + if (ret >= 0) + atomic_inc(&nr_configured_hkid); + + return ret; } EXPORT_SYMBOL_FOR_KVM(tdx_guest_keyid_alloc); void tdx_guest_keyid_free(unsigned int keyid) { ida_free(&tdx_guest_keyid_pool, keyid); + atomic_dec(&nr_configured_hkid); } EXPORT_SYMBOL_FOR_KVM(tdx_guest_keyid_free); -- 2.53.0.310.g728cabbaf7-goog