| Message ID | 20240909124721.1672199-1-sebastianene@google.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | arm64: ptdump: View the second stage page-tables | expand |
On Mon, 09 Sep 2024 12:47:16 +0000, Sebastian Ene wrote: > This series extends the ptdump support to allow dumping the guest > stage-2 pagetables. When CONFIG_PTDUMP_STAGE2_DEBUGFS is enabled, ptdump > registers the new following files under debugfs: > - /sys/debug/kvm/<guest_id>/stage2_page_tables > - /sys/debug/kvm/<guest_id>/stage2_levels > - /sys/debug/kvm/<guest_id>/ipa_range > > [...] Applied to next, thanks! [1/5] KVM: arm64: Move pagetable definitions to common header commit: 29caeda359da15d16963096043cda39530f81cc4 [2/5] arm64: ptdump: Expose the attribute parsing functionality commit: acc3d3a8176651a839056c7da4b925ea0bcc38c2 [3/5] arm64: ptdump: Use the ptdump description from a local context commit: 9182301a7bd2564fb050ade9820333c8b1adfcc2 [4/5] arm64: ptdump: Don't override the level when operating on the stage-2 tables commit: 79c4c7284f92d5e780c8532c343ca2cacfaf5125 [5/5] KVM: arm64: Register ptdump with debugfs on guest creation commit: 7c4f73548ed15476daf1101f66648085eda65067 Cheers, M.
Hi, This series extends the ptdump support to allow dumping the guest stage-2 pagetables. When CONFIG_PTDUMP_STAGE2_DEBUGFS is enabled, ptdump registers the new following files under debugfs: - /sys/debug/kvm/<guest_id>/stage2_page_tables - /sys/debug/kvm/<guest_id>/stage2_levels - /sys/debug/kvm/<guest_id>/ipa_range This allows userspace tools (eg. cat) to dump the stage-2 pagetables by reading the 'stage2_page_tables' file. The output format has the following fields: <IPA range> <size> <level> <access permissions> <mem_attributes> Below is the output of a guest stage-2 pagetable dump running under Qemu. After a VM is created, the following files are available: # cat /sys/kernel/debug/kvm/256-4/stage2_levels 4 # cat /sys/kernel/debug/kvm/256-4/ipa_range 44 # cat /sys/kernel/debug/kvm/256-4/stage2_page_tables ---[ Guest IPA ]--- 0x0000000000000000-0x0000000001000000 16M 2 0x0000000001000000-0x0000000001020000 128K 3 0x0000000001020000-0x0000000001021000 4K 3 R W X AF 0x0000000001021000-0x0000000001200000 1916K 3 0x0000000001200000-0x0000000040000000 1006M 2 0x0000000040000000-0x0000000080000000 1G 0 0x0000000080000000-0x0000000081200000 18M 2 R W AF BLK 0x0000000081200000-0x0000000081a00000 8M 2 R W X AF BLK 0x0000000081a00000-0x0000000081c00000 2M 2 R W AF BLK 0x0000000081c00000-0x0000000082200000 6M 2 R W X AF BLK 0x0000000082200000-0x0000000082400000 2M 2 R W AF BLK 0x0000000082400000-0x0000000082800000 4M 2 R W X AF BLK 0x0000000082800000-0x0000000082a00000 2M 2 R W AF BLK 0x0000000082a00000-0x0000000082c00000 2M 2 0x0000000082c00000-0x0000000083200000 6M 2 R W X AF BLK 0x0000000083200000-0x0000000083400000 2M 2 0x0000000083400000-0x0000000083a00000 6M 2 R W X AF BLK 0x0000000083a00000-0x000000008fe00000 196M 2 0x000000008fe00000-0x0000000090000000 2M 2 R W AF BLK 0x0000000090000000-0x0000000099400000 148M 2 0x0000000099400000-0x0000000099600000 2M 2 R W X AF BLK 0x0000000099600000-0x000000009b600000 32M 2 0x000000009b600000-0x000000009be00000 8M 2 R W X AF BLK 0x000000009be00000-0x000000009c000000 2M 2 R W AF BLK 0x000000009c000000-0x00000000c0000000 576M 2 Changelog: v9 -> current: * fixed an issue reported by Mark - when using CONFIG_ARM64_VA_BITS=47 and CONFIG_PAGE_SIZE_16KB=y ptdump was entering a check used for kernel pagetables to interpret the folded levels, thus overriding the current page table level. This was resulting in bogus output when ran on the stage-2 pagetables. * folded the Kconfig patch in the one that introduces kvm/ptdump.c as suggested by Vincent. Collected Vincent's Reviewed-by tag, thanks. * applied Mark's sugegstion to use the callbacks by construct when interpretting the level and the ipa_bits instead of a string comparison on the pseudo-file. * fixed a bunch of nits v8 -> v9: * squashed the last 3 patches and separated the Kconfig change as the last patch. * updated the commit message of the 3rd patch * printing level numbers instead of names as suggested by Mark * fixed one return code to ERR_PTR(-ENOMEM) as spotted by Vincent * dropped a barely empty header 'kvm_ptdump.h' * general cosmetic changes 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" Links to previous versions: v9: https://lore.kernel.org/all/20240827084549.45731-1-sebastianene@google.com/ v8: https://lore.kernel.org/all/20240816123906.3683425-1-sebastianene@google.com/ v7: https://lore.kernel.org/all/20240621123230.1085265-1-sebastianene@google.com/ v6: https://lore.kernel.org/all/20240220151035.327199-1-sebastianene@google.com/ v5: https://lore.kernel.org/all/20240207144832.1017815-2-sebastianene@google.com/ Thanks, Sebastian Sebastian Ene (5): KVM: arm64: Move pagetable definitions to common header arm64: ptdump: Expose the attribute parsing functionality arm64: ptdump: Use the ptdump description from a local context arm64: ptdump: Don't override the level when operating on the stage-2 tables KVM: arm64: Register ptdump with debugfs on guest creation arch/arm64/include/asm/kvm_host.h | 6 + arch/arm64/include/asm/kvm_pgtable.h | 42 +++++ arch/arm64/include/asm/ptdump.h | 42 ++++- arch/arm64/kvm/Kconfig | 17 ++ arch/arm64/kvm/Makefile | 1 + arch/arm64/kvm/arm.c | 1 + arch/arm64/kvm/hyp/pgtable.c | 42 ----- arch/arm64/kvm/ptdump.c | 268 +++++++++++++++++++++++++++ arch/arm64/mm/ptdump.c | 70 ++----- 9 files changed, 396 insertions(+), 93 deletions(-) create mode 100644 arch/arm64/kvm/ptdump.c