From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f202.google.com (mail-pf1-f202.google.com [209.85.210.202]) (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 244E521FF26 for ; Wed, 27 Aug 2025 00:05:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756253145; cv=none; b=vFRZ/FKAAZEoIHofLKPOyruD1RJXsm1+mK5d3F73i4Kk61dvTmbeic4PlKt+X7gchilrQYNmy5SzqZs04MFCdHpNPpgD6Ypb5DEEZ24dlHZ4vc073jo7KrKDYiSH8HzCey7oKr5MzD676ag6IB2um2ir0xEbuLovg/AzitEAO18= 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=209.85.210.202 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="TxEF2nTJ" Received: by mail-pf1-f202.google.com with SMTP id d2e1a72fcca58-771b23c0a6bso4708733b3a.0 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=KMKz4URkZyxePr8EbXdMVVgNkxYWVz4052/HlPKHU6QAancRv/zmcemeyyqAGWnTVY H6TIrxU14muxcK1X6AFx3EKuqUfn0u2icAwfajK595bExi5CnXNL5XF9nImD7bfl4DZ6 yg4jPBqNu9ha8iP1DDOoJyU5PtWZtZKXq/b/1VY7Wa0NTTxPRCkpsg8rmFSsypHIkX+8 hfHfzt3fbnUMQvoVcVFs294ctxfSMikp7jTKxnfXc9YJct61MAfUfRi1Yx8dPV0d/vqv XYQQi2XrWbzmZcyvTVLFVZ42vwLlF321Qd7veTdkZiWfxvF6oDHP/OWAJ/s8TyaNv5zZ vzvw== X-Gm-Message-State: AOJu0YxdzuBNnHK0QwAH91pfyCHjcNLy+dwD1l9yQY0XVdXuE21cNKaN aEZaBA00d+lUMPJY1L+aCZf1ZO4cZ7cdvsZrw1522jvLkwBvtVsv4OQnagEFlifUcEDnmJSyxhU qL0g9yA== 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: kvm@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-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; - atomic64_inc(&kvm_tdx->nr_premapped); + kvm_tdx->nr_premapped++; return 0; } @@ -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); - 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; return 0; @@ -2846,7 +2846,7 @@ static int tdx_td_finalize(struct kvm *kvm, struct kvm_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; cmd->hw_error = tdh_mr_finalize(&kvm_tdx->td); @@ -3160,7 +3160,7 @@ static int tdx_gmem_post_populate(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, goto out; } - KVM_BUG_ON(atomic64_dec_return(&kvm_tdx->nr_premapped) < 0, kvm); + KVM_BUG_ON(--kvm_tdx->nr_premapped < 0, kvm); if (arg->flags & KVM_TDX_MEASURE_MEMORY_REGION) { for (i = 0; i < PAGE_SIZE; i += 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; /* For KVM_TDX_INIT_MEM_REGION. */ - atomic64_t nr_premapped; + unsigned long nr_premapped; /* * Prevent vCPUs from TD entry to ensure SEPT zap related SEAMCALLs do -- 2.51.0.268.g9569e192d0-goog