From nobody Fri Oct 3 19:17:25 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 4EE9E21FF3F for ; Wed, 27 Aug 2025 00:05:44 +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=1756253145; cv=none; b=E9iRowNhfMxKlQWIXRD9hx0hrkAyyVCeghTphbJptxIenifURgLuE9s5QeWblcWlV/nvaqnvRHIj5KXzbEgSvs+w7mr3gW5ciUniDmIWXano6YkHbWu+dvRsUxsiza0VAs8mEKUJ/MAUQ1OUKiH9Pu6IuCVn/vStXUcUb5vbExc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756253145; c=relaxed/simple; bh=LPaxkW9YyCXUJeIK8cRJGK+UjtY30XS0fpBptMGlvUg=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=ReJBExVuirPq+ER2rUpZ8BZNreCnvhmx7stTkDUlYI+QNCNzmFkRSpW7qi/rtU1HTV1CmI3Up0RtvL2nhYFHsbKwXyS166ocpfJzr01EcmRlxDZe6Ce8TP2eCltIczZu+yzdvdJGqq3geAf+PoKH3tzELAsovq70Fc0Pp663pro= 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=TxEF2nTJ; 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="TxEF2nTJ" Received: by mail-pf1-f201.google.com with SMTP id d2e1a72fcca58-76e2eb6d2baso11635006b3a.3 for ; Tue, 26 Aug 2025 17:05:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1756253143; x=1756857943; 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=FsJkpNgJKrVlrQ0kYYDnZ364wlXe53Et8BwiZ80i0+M=; b=TxEF2nTJSm7I/lUichMiss/0dvcKnEKDsf82vrVDpgCCQjNJm0HP0v6S2+6VYI6S89 calCE3XGypg6kPehwicAXodOrXQXCZ9deEDjA3XEiJ/7/rng4LKDFZ6DO9Z5GbSUHKsF TpNfLMWj+ZVNMDslsamUf8xUSjm51BxWOKbpffAdV7ZyMOFiwNSNmoqcggWqWbFpaGL2 jns5LFUzHCFEBKvbi8j25BZwm9EUfEUMF2dxxEH2eMKCRIVwdwcffum1QKNPymcOug0M m2NTuqt3YxcTLWrVdQB2r8OeB86JqdltJviAfRzBVF/NQzuBOupGtyCc/es8jZ9NzsE0 umRw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1756253143; x=1756857943; 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=FsJkpNgJKrVlrQ0kYYDnZ364wlXe53Et8BwiZ80i0+M=; b=fy4pPTUZKQ7W7Z398kLRCl9y9XpC8ZihL2z3xIEUG/MT2IRP+w1MgSd/I4xobnhxp6 TL+khkaFCamhZ/swr92+hdM884AtHHnxvS4Ltd3dE0a212ZoQABcO7DTDosUqe5geuP+ 788jYp89sI0ETmFA13XeICmm+W3zaTcqDJmOIroySCS96pyXdbxs+AaFplRP7nNIL9Hw 3E2SHETv/7UdI1WmnxuxMXO8EIWOW82giEmPTUBj9tsp2LaAEpev+8AkNRm2rmM69rQV 1yOQgRLpk3VKotqTFMwGFpMN8VOvJv3nFUAJDEg9eWQFWdAx1Y7uROyuv3ywx9KbAnvG 7MsQ== X-Forwarded-Encrypted: i=1; AJvYcCVUv66CPzQIwWAYJl4WI9qRZoXTD08j5HpVe6StPxM92qm690IW9DENkxKoMlbtqiPKCJMhpCQFPQkH1vs=@vger.kernel.org X-Gm-Message-State: AOJu0Yz+9LzZF4YQLUZ+qUfX1xJv5m/81km2dzunaZdm32nSs/Si+RLO Zvl85aFcVAKnQNjT82GBBuc1Fx0s7FMTJSaZP2EmGX7lrtN0HyifUUhVxUdThmiIZjIFikgO5a3 rk4TWmg== X-Google-Smtp-Source: AGHT+IEpi55G8voNDVUumr/uaCI0zU1p73RuojkrRDx6WiI41KFFc3w7odsA7AW9Ablcl98PDu4S12vgqWw= X-Received: from pjvb15.prod.google.com ([2002:a17:90a:d88f:b0:311:c197:70a4]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:5493:b0:243:15b9:7661 with SMTP id adf61e73a8af0-24340d71cfcmr26934393637.59.1756253143613; Tue, 26 Aug 2025 17:05:43 -0700 (PDT) Reply-To: Sean Christopherson Date: Tue, 26 Aug 2025 17:05:21 -0700 In-Reply-To: <20250827000522.4022426-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250827000522.4022426-1-seanjc@google.com> X-Mailer: git-send-email 2.51.0.268.g9569e192d0-goog Message-ID: <20250827000522.4022426-12-seanjc@google.com> Subject: [RFC PATCH 11/12] KVM: TDX: Track nr_premapped as an "unsigned long", not an "atomic64_t" From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Michael Roth , Yan Zhao , Ira Weiny , Vishal Annapurve , Rick Edgecombe Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Track the number of premapped pfns as a non-atomic variable as all usage is guarded by slots_lock, and KVM now asserts as much. Note, slots_lock has always effectively guarded nr_premapped since TDX support landed, the use of an atomic64_t was likely a leftover from development that was never cleaned up. Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/tdx.c | 8 ++++---- arch/x86/kvm/vmx/tdx.h | 2 +- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index 27941defb62e..5d2bb27f22da 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -1639,7 +1639,7 @@ static int tdx_sept_set_private_spte(struct kvm *kvm,= gfn_t gfn, if (KVM_BUG_ON(kvm->arch.pre_fault_allowed, kvm)) return -EIO; =20 - atomic64_inc(&kvm_tdx->nr_premapped); + kvm_tdx->nr_premapped++; return 0; } =20 @@ -1771,7 +1771,7 @@ static int tdx_sept_zap_private_spte(struct kvm *kvm,= gfn_t gfn, if (tdx_is_sept_zap_err_due_to_premap(kvm_tdx, err, entry, level)) { lockdep_assert_held(&kvm->slots_lock); =20 - if (KVM_BUG_ON(atomic64_dec_return(&kvm_tdx->nr_premapped) < 0, kvm)) + if (KVM_BUG_ON(--kvm_tdx->nr_premapped < 0, kvm)) return -EIO; =20 return 0; @@ -2846,7 +2846,7 @@ static int tdx_td_finalize(struct kvm *kvm, struct kv= m_tdx_cmd *cmd) * Pages are pending for KVM_TDX_INIT_MEM_REGION to issue * TDH.MEM.PAGE.ADD(). */ - if (atomic64_read(&kvm_tdx->nr_premapped)) + if (kvm_tdx->nr_premapped) return -EINVAL; =20 cmd->hw_error =3D tdh_mr_finalize(&kvm_tdx->td); @@ -3160,7 +3160,7 @@ static int tdx_gmem_post_populate(struct kvm *kvm, gf= n_t gfn, kvm_pfn_t pfn, goto out; } =20 - KVM_BUG_ON(atomic64_dec_return(&kvm_tdx->nr_premapped) < 0, kvm); + KVM_BUG_ON(--kvm_tdx->nr_premapped < 0, kvm); =20 if (arg->flags & KVM_TDX_MEASURE_MEMORY_REGION) { for (i =3D 0; i < PAGE_SIZE; i +=3D TDX_EXTENDMR_CHUNKSIZE) { diff --git a/arch/x86/kvm/vmx/tdx.h b/arch/x86/kvm/vmx/tdx.h index ca39a9391db1..04ba9ea3e0ba 100644 --- a/arch/x86/kvm/vmx/tdx.h +++ b/arch/x86/kvm/vmx/tdx.h @@ -37,7 +37,7 @@ struct kvm_tdx { struct tdx_td td; =20 /* For KVM_TDX_INIT_MEM_REGION. */ - atomic64_t nr_premapped; + unsigned long nr_premapped; =20 /* * Prevent vCPUs from TD entry to ensure SEPT zap related SEAMCALLs do --=20 2.51.0.268.g9569e192d0-goog