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AJvYcCW9x+MrLgTxqmEpQf9i/O/P0+h4+prpIyFkE5cePRbPfiDubeYyXhsSn8NSXHHxlvCnM8pI8/LkHBZ0+bFuDbqClGLiI2Ek69hau/JRjLdf3fUDZV8= X-Gm-Message-State: AOJu0Yxy5ASBzBT6sdVZu3ao4t5dnKUzG1Mbrrja7Enlb3M6LYTguXrf DJODqNDrd2WVSOtggJ4UErAqvY1dq0V8NprCgAT2UMQU4eSrm6KQjd0+Ihkre90d28Eg29zRmFt 9lv6DWywcHzO3hndgclf58U8peg== X-Google-Smtp-Source: AGHT+IGB0VFbMJX9PjdgC8p1ueT+M9NCul0doNH3FtI58DbCoos4szbVwer8lzRUhSiaxjA5OYmf50ifvUmcB9uy4qA= X-Received: from sebkvm.c.googlers.com ([fda3:e722:ac3:cc00:28:9cb1:c0a8:cd5]) (user=sebastianene job=sendgmr) by 2002:a17:906:d7d6:b0:a83:9526:b28c with SMTP id a640c23a62f3a-a839526b3e8mr185866b.1.1723811953902; Fri, 16 Aug 2024 05:39:13 -0700 (PDT) Date: Fri, 16 Aug 2024 12:39:00 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.46.0.184.g6999bdac58-goog Message-ID: <20240816123906.3683425-1-sebastianene@google.com> Subject: [PATCH v8 0/6] arm64: ptdump: View the second stage page-tables From: Sebastian Ene To: akpm@linux-foundation.org, alexghiti@rivosinc.com, ankita@nvidia.com, ardb@kernel.org, catalin.marinas@arm.com, christophe.leroy@csgroup.eu, james.morse@arm.com, vdonnefort@google.com, mark.rutland@arm.com, maz@kernel.org, oliver.upton@linux.dev, rananta@google.com, ryan.roberts@arm.com, sebastianene@google.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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240816_053917_916986_9F865F77 X-CRM114-Status: GOOD ( 26.66 ) 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 series extends the ptdump support to allow dumping the guest stage-2 pagetables. 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 dump 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 v7: https://lore.kernel.org/all/20240621123230.1085265-1-sebastianene@google.com/ Link to v6: https://lore.kernel.org/all/20240220151035.327199-1-sebastianene@google.com/ 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: v7 -> v8: * applied Will's feedback and prefixed the exported structure names with ptdump_ * dropped PTE_CONT and PTE_NG attribute parsing from Oliver's suggestion * fixed spurious BLK annotation reported by Vincent * repurposed `stage2_levels` debugfs file to show the number of the levels * tried changing the order of the patches: "5/6 Initialize the ptdump parser with stage-2 attributes" before exposing the debugfs file but ended up keeping the same order as this depends on the later one. v6 -> v7: * Reworded commit for this patch : [PATCH v6 2/6] arm64: ptdump: Expose the attribute parsing functionality * fixed minor conflicts in the struct pg_state definition * moved the kvm_ptdump_guest_registration in the * kvm_arch_create_vm_debugfs * reset the parse state before walking the pagetables * copy the level name to the pg_level buffer v5 -> v6: * 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 | 14 ++ arch/arm64/kvm/Makefile | 1 + arch/arm64/kvm/arm.c | 2 + arch/arm64/kvm/hyp/pgtable.c | 42 ----- arch/arm64/kvm/kvm_ptdump.h | 20 ++ arch/arm64/kvm/ptdump.c | 262 +++++++++++++++++++++++++++ arch/arm64/mm/ptdump.c | 66 ++----- 9 files changed, 400 insertions(+), 91 deletions(-) create mode 100644 arch/arm64/kvm/kvm_ptdump.h create mode 100644 arch/arm64/kvm/ptdump.c