| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <ZoK7sw73g94iP050@google.com> Date: Mon, 1 Jul 2024 14:22:43 +0000 From: Sebastian Ene <sebastianene@...gle.com> To: Oliver Upton <oliver.upton@...ux.dev> Cc: akpm@...ux-foundation.org, alexghiti@...osinc.com, ankita@...dia.com, ardb@...nel.org, catalin.marinas@....com, christophe.leroy@...roup.eu, james.morse@....com, vdonnefort@...gle.com, mark.rutland@....com, maz@...nel.org, rananta@...gle.com, ryan.roberts@....com, shahuang@...hat.com, suzuki.poulose@....com, will@...nel.org, yuzenghui@...wei.com, kvmarm@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, kernel-team@...roid.com Subject: Re: [PATCH v7 0/6] arm64: ptdump: View the second stage page-tables On Fri, Jun 28, 2024 at 09:25:26PM +0000, Oliver Upton wrote: Hello Oliver, > Hi Seb, > > I think we're getting closer on this series, thanks for reposting it. In > addition to polishing up the KVM side of things, I'd like to have acks > on the ptdump changes (patches 2-3). > > Will + Catalin, any concerns? > > -- > Thanks, > Oliver Thanks for the feedback, I will spin a v8 later this week if there are no more findings on the remaining patches. Thanks, Sebastian > > On Fri, Jun 21, 2024 at 12:32:24PM +0000, Sebastian Ene wrote: > > 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/<guest_id>/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: > > <IPA range> <size> <descriptor type> <access permissions> <mem_attributes> > > > > 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 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: > > 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/<guest_id>/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 | 272 +++++++++++++++++++++++++++ > > arch/arm64/mm/ptdump.c | 50 +---- > > 9 files changed, 402 insertions(+), 83 deletions(-) > > create mode 100644 arch/arm64/kvm/kvm_ptdump.h > > create mode 100644 arch/arm64/kvm/ptdump.c > > > > -- > > 2.45.2.741.gdbec12cfda-goog > > > > To unsubscribe from this group and stop receiving emails from it, send an email to kernel-team+unsubscribe@...roid.com. >
Powered by blists - more mailing lists