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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E36AACCFA04 for ; Tue, 4 Nov 2025 18:02:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:Cc:To:From: Subject:Message-ID:References:Mime-Version:In-Reply-To:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=z7TAMX5tgRxcaQgmnIz2dr5/J34h/wClq0GmkAjx/eU=; b=syNocl0L3FLd2b2P9uxw7ibjz+ GgbmaeKiy82BQ55zZlg3xH5jeK6o6rsBSczkdE2lNzA5iR3tYmsLSqM2kH2TLldSaxqmgkXIZUVdW /0CZs1Bmz6H5XEJcr1DlUkJrlVx0rUy8mdPVL+/54A4pK9ewUN0VKMbX9W20PXTBMDxMIUyQ08WDB b/spS8P3WBjHns+3o6EMHkMMe0j+jWBHFzWWJmD4AETPFm82sV/yvkUzIEdZRQvhACacsGvABAVxI nowJO3PNx6dBSPtlI7zwtvT9nuN4u1K+Aec8QWEadGcHHWnXU8KEtW5grVjGQ8DDgE+KRngNjNm6j ceajR6hQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vGLMZ-0000000CKER-3xXI; Tue, 04 Nov 2025 18:02:35 +0000 Received: from mail-pg1-x54a.google.com ([2607:f8b0:4864:20::54a]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vGLMX-0000000CKD6-1xWm for linux-arm-kernel@lists.infradead.org; Tue, 04 Nov 2025 18:02:34 +0000 Received: by mail-pg1-x54a.google.com with SMTP id 41be03b00d2f7-b55283ff3fcso4043684a12.3 for ; Tue, 04 Nov 2025 10:02:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1762279351; x=1762884151; darn=lists.infradead.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=z7TAMX5tgRxcaQgmnIz2dr5/J34h/wClq0GmkAjx/eU=; b=CIcncL6ZiHm24mQDQPyBWq3Ar2EZWWn/pvbLdnjD9UiboDrc51VsxM/VsMfOAC3Jh3 w3VTlOSiyWa2mLG9GC89C7C1vJkKHrT4ac1XD8iXZSR9o/yXiUzgeLlpJSKxJWB9dvcm 32+nvJGdbiZ56GijykgX85qL04ZPVjKgVJ4dvmwp624+S6rdR5ZSaZP75+A5U9jyWG1Q DOi35F9QO2lYdxR9eIrffWE9X0EQ5oAqbbt3PfatdEy536GEGXMqeOha5P5Nl+dL98+x HtyqBmbpcMLsjrbnK8tyNIa1TtgD73nT6YdJoDbNtlyu9i8zA2VycJB4G5G5U/zMgtY1 F9IQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1762279351; x=1762884151; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=z7TAMX5tgRxcaQgmnIz2dr5/J34h/wClq0GmkAjx/eU=; b=BHPfl+T0epGHkXe028B8IRU3ZaHGCdPAsurv28Jqp2h2+9Zz8fGf7fej0Ms8t64QX+ wfcKF+4xwIfJnX/p0zQLVEqhRSfU1CgiVloA4FAs6KVK6olmQAIx6wdEpmiHD/IjjNQW tpmmrlisElBZZHbOtb6iTYoyN+lK+skMHxyqf3jdxx6UkOXXVri4sTSPEKc9tlAJBVN+ TEiZBXWunqDg0TNCNp0tNiBZhG8m2RszkFZGq8U/V16FnnSNTr8hA2ujeUe80YxMlvlX Nq1luqaxietvaTwcmvLGTG5klRQM/zH/rCaYCzKar7xDk9M/SJJtCo6TtkMB01uQCZvV c5xg== X-Forwarded-Encrypted: i=1; AJvYcCU3MSaTafhI7z7j5drNPhAGwoEXS0HKvQBxJdeXhPoW/B5K2ZadfS9qUBlMowR7am1qEutxmi7JkbwN1GDWajMS@lists.infradead.org X-Gm-Message-State: AOJu0Yw29vJnYDM4N61Kayewwk/HzhOW5LOuTRQ2NsACl5ufrh0Q4u+Q YKyffJqo1QWso+YykFnL8yXu5PyGMNoRpt/VfvSj90PAL2rUeL1PwHpSEgs//aRG1gcmoLLOua+ a/GAkRg== X-Google-Smtp-Source: AGHT+IEToeihVC8rNRp4WXHuCXbja7cJV9DF8/gVM9lRFkFysIMA8abH+TqAL0waWRxDGRap6/agKlo3e+8= X-Received: from pjbmv10.prod.google.com ([2002:a17:90b:198a:b0:340:d512:22dc]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a21:6d92:b0:32b:7222:7459 with SMTP id adf61e73a8af0-34f8591c355mr151990637.34.1762279351036; Tue, 04 Nov 2025 10:02:31 -0800 (PST) Date: Tue, 4 Nov 2025 10:02:26 -0800 In-Reply-To: <31da959f-d004-4ae0-a6a7-d5d31b646b70@linux.intel.com> Mime-Version: 1.0 References: <20251030200951.3402865-1-seanjc@google.com> <20251030200951.3402865-28-seanjc@google.com> <31da959f-d004-4ae0-a6a7-d5d31b646b70@linux.intel.com> Message-ID: Subject: Re: [PATCH v4 27/28] KVM: TDX: Bug the VM if extending the initial measurement fails From: Sean Christopherson To: Binbin Wu Cc: Marc Zyngier , Oliver Upton , Tianrui Zhao , Bibo Mao , Huacai Chen , Madhavan Srinivasan , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Paolo Bonzini , "Kirill A. Shutemov" , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, kvm@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, x86@kernel.org, linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org, Ira Weiny , Kai Huang , Michael Roth , Yan Zhao , Vishal Annapurve , Rick Edgecombe , Ackerley Tng Content-Type: text/plain; charset="us-ascii" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251104_100233_503891_6A6C7D77 X-CRM114-Status: GOOD ( 20.10 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Nov 04, 2025, Binbin Wu wrote: > > > On 10/31/2025 4:09 AM, Sean Christopherson wrote: > > WARN and terminate the VM if TDH_MR_EXTEND fails, as extending the > > measurement should fail if and only if there is a KVM bug, or if the S-EPT > > mapping is invalid. Now that KVM makes all state transitions mutually > > exclusive via tdx_vm_state_guard, it should be impossible for S-EPT > > mappings to be removed between kvm_tdp_mmu_map_private_pfn() and > > tdh_mr_extend(). > > > > Holding slots_lock prevents zaps due to memslot updates, > > filemap_invalidate_lock() prevents zaps due to guest_memfd PUNCH_HOLE, > > vcpu->mutex locks prevents updates from other vCPUs, kvm->lock prevents > > VM-scoped ioctls from creating havoc (e.g. by creating new vCPUs), and all > > usage of kvm_zap_gfn_range() is mutually exclusive with S-EPT entries that > > can be used for the initial image. > > > > For kvm_zap_gfn_range(), the call from sev.c is obviously mutually > > exclusive, TDX disallows KVM_X86_QUIRK_IGNORE_GUEST_PAT so the same goes > > for kvm_noncoherent_dma_assignment_start_or_stop(), and > > __kvm_set_or_clear_apicv_inhibit() is blocked by virtue of holding all > > VM and vCPU mutexes (and the APIC page has its own non-guest_memfd memslot > > Nit: > It sounds like TDX is using the memslot for the APIC page, but for a TD, the > memslot for the APIC page is never initialized or used? Oh! Good point. I'll tweak that snippet when applying.