From patchwork Tue Feb 20 15:10:29 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Ene X-Patchwork-Id: 13564143 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 C56C5C54788 for ; Tue, 20 Feb 2024 15:12:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:From:Subject:Message-ID: Mime-Version:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To: References:List-Owner; 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AJvYcCV5bF78seNivtaFXz8KXfodMq26O/VtdRtBOHQHbTE7mh0qAMJt6bQduBfgH0F40RVz10U5I3rwp/44cy5/+BcNZat9HjcZCvtXepRAy8Htmuct6L8= X-Gm-Message-State: AOJu0YznkeizURYzqos60a4hHjd1tLnvZOoUsItCbTlKhQDtc2+0k3et /i0HXkYWI8yBkGqza7oAkQ5sFBrssNFcWehu0EB/EaxjHXIrYBEgfBaliL8fX7TgpnorYT3KpNV pGoaLCTj/3LvKUGioaFvfI2qi6Q== X-Google-Smtp-Source: AGHT+IHawj15gJxsvtR7YjJHEveUJ4WwPausjIgV44eHILmnRZ0cyOqUs/m7BsqWzl/SQPAk6PdNzK5cvmg0Wu4bYlg= X-Received: from sebkvm.c.googlers.com ([fda3:e722:ac3:cc00:28:9cb1:c0a8:cd5]) (user=sebastianene job=sendgmr) by 2002:a0d:d7d1:0:b0:608:22f1:c8e4 with SMTP id z200-20020a0dd7d1000000b0060822f1c8e4mr1953137ywd.6.1708441892365; Tue, 20 Feb 2024 07:11:32 -0800 (PST) Date: Tue, 20 Feb 2024 15:10:29 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.44.0.rc0.258.g7320e95886-goog Message-ID: <20240220151035.327199-1-sebastianene@google.com> Subject: [PATCH v6 0/6] arm64: ptdump: View the second stage page-tables From: Sebastian Ene To: catalin.marinas@arm.com, gshan@redhat.com, james.morse@arm.com, mark.rutland@arm.com, maz@kernel.org, oliver.upton@linux.dev, rananta@google.com, ricarkol@google.com, ryan.roberts@arm.com, shahuang@redhat.com, suzuki.poulose@arm.com, will@kernel.org, yuzenghui@huawei.com Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kernel-team@android.com, vdonnefort@google.com, Sebastian Ene X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240220_071138_737352_767CDE0C X-CRM114-Status: GOOD ( 24.24 ) 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 Hi, This is the first part of the series which enables dumping of the guest stage-2 pagetables. The support for dumping the host stage-2 pagetables which is pKVM specific will be part of a follow-up series as per the feedback received in v4. When CONFIG_PTDUMP_STAGE2_DEBUGFS is enabled, ptdump registers '/sys/debug/kvm//stage2_page_tables' entry with debugfs upon guest creation. This allows userspace tools (eg. cat) to dump the stage-2 pagetables by reading the registered file. Reading the debugfs file shows stage-2 memory ranges in following format: Below is the output of a guest stage-2 pagetable mappings running under Qemu: ---[ IPA bits 33 start lvl 2 ]--- 0x0000000000000000-0x0000000080000000 2G PGD 0x0000000080000000-0x0000000080c00000 12M PGD R W AF BLK 0x0000000080c00000-0x0000000080e00000 2M PGD XN R W AF BLK 0x0000000080e00000-0x0000000081000000 2M PGD R W AF BLK 0x0000000081000000-0x0000000081400000 4M PGD XN R W AF BLK 0x0000000081400000-0x000000008fe00000 234M PGD 0x000000008fe00000-0x0000000090000000 2M PGD XN R W AF BLK 0x0000000090000000-0x00000000fa000000 1696M PGD 0x00000000fa000000-0x00000000fe000000 64M PGD XN R W AF BLK 0x00000000fe000000-0x0000000100000000 32M PGD 0x0000000100000000-0x0000000101c00000 28M PGD XN R W AF BLK 0x0000000101c00000-0x0000000102000000 4M PGD 0x0000000102000000-0x0000000102200000 2M PGD XN R W AF BLK 0x0000000102200000-0x000000017b000000 1934M PGD 0x000000017b000000-0x0000000180000000 80M PGD XN R W AF BLK Link to v5: https://lore.kernel.org/all/20240207144832.1017815-2-sebastianene@google.com/ Link to v4: https://lore.kernel.org/all/20231218135859.2513568-2-sebastianene@google.com/ Link to v3: https://lore.kernel.org/all/20231115171639.2852644-2-sebastianene@google.com/ Changelog: v5 -> current: * don't return an error if the kvm_arch_create_vm_debugfs fails to initialize (ref. https://lore.kernel.org/all/20240216155941.2029458-1-oliver.upton@linux.dev/) * fix use-after-free suggested by getting a reference to the KVM struct while manipulating the debugfs files and put the reference on the file close. * do all the allocations at once for the ptdump parser state tracking and simplify the initialization. * move the ptdump parser state initialization as part of the file_open * create separate files for printing the guest stage-2 pagetable configuration such as: the start level of the pagetable walk and the number of bits used for the IPA space representation. * fixed the wrong header format for the newly added file * include missing patch which hasn't been posted on the v5: "KVM-arm64-Move-pagetable-definitions-to-common-heade.patch" v4 -> v5: * refactorization: split the series into two parts as per the feedback received from Oliver. Introduce the base support which allows dumping of the guest stage-2 pagetables. * removed the *ops* struct wrapper built on top of the file_ops and simplify the ptdump interface access. * keep the page table walker away from the ptdump specific code v3 -> current_version: * refactorization: moved all the **KVM** specific components under kvm/ as suggested by Oliver. Introduced a new file arm64/kvm/ptdump.c which handled the second stage translation. re-used only the display portion from mm/ptdump.c * pagetable snapshot creation now uses memory donated from the host. The memory is no longer shared with the host as this can pose a security risk if the host has access to manipulate the pagetable copy while the hypervisor iterates it. * fixed a memory leak: while memory was used from the memcache for building the snapshot pagetable, it was no longer giving back the pages to the host for freeing. A separate array was introduced to keep track of the pages allocated from the memcache. v2 -> v3: * register the stage-2 debugfs entry for the host under /sys/debug/kvm/host_stage2_page_tables and in /sys/debug/kvm//stage2_page_tables for guests. * don't use a static array for parsing the attributes description, generate it dynamically based on the number of pagetable levels * remove the lock that was guarding the seq_file private inode data, and keep the data private to the open file session. * minor fixes & renaming of CONFIG_NVHE_EL2_PTDUMP_DEBUGFS to CONFIG_PTDUMP_STAGE2_DEBUGFS v1 -> v2: * use the stage-2 pagetable walker for dumping descriptors instead of the one provided by ptdump. * support for guests pagetables dumping under VHE/nVHE non-protected Thanks, Sebastian Ene (6): KVM: arm64: Move pagetable definitions to common header arm64: ptdump: Expose the attribute parsing functionality arm64: ptdump: Use the mask from the state structure KVM: arm64: Register ptdump with debugfs on guest creation KVM: arm64: Initialize the ptdump parser with stage-2 attributes KVM: arm64: Expose guest stage-2 pagetable config to debugfs arch/arm64/include/asm/kvm_pgtable.h | 42 +++++ arch/arm64/include/asm/ptdump.h | 42 ++++- arch/arm64/kvm/Kconfig | 13 ++ arch/arm64/kvm/Makefile | 1 + arch/arm64/kvm/debug.c | 8 + arch/arm64/kvm/hyp/pgtable.c | 42 ----- arch/arm64/kvm/kvm_ptdump.h | 20 ++ arch/arm64/kvm/ptdump.c | 270 +++++++++++++++++++++++++++ arch/arm64/mm/ptdump.c | 49 +---- 9 files changed, 405 insertions(+), 82 deletions(-) create mode 100644 arch/arm64/kvm/kvm_ptdump.h create mode 100644 arch/arm64/kvm/ptdump.c