Messages in this thread | | | Date | Thu, 19 Oct 2023 14:40:21 +0000 | Subject | [PATCH v2 00/11] arm64: ptdump: View the second stage page-tables | From | Sebastian Ene <> |
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Hi,
This can be used as a debugging tool for dumping the second stage page-tables under debugfs.
From the previous feedback I re-worked the series and added support for guest page-tables dumping under VHE & nVHE configuration. I extended the list of reviewers as I missed the interested parties in the first round.
When CONFIG_NVHE_EL2_PTDUMP_DEBUGFS is enabled under pKVM environment, ptdump registers the 'host_stage2_kernel_page_tables' entry with debugfs. Guests are registering a file named '%u_guest_stage2_page_tables' when they are created.
This allows us to dump the host stage-2 page-tables with the following command: cat /sys/kernel/debug/host_stage2_kernel_page_tables.
The output is showing the entries in the following format: <IPA range> <size> <descriptor type> <access permissions> <mem_attributes>
The tool interprets the pKVM ownership annotation stored in the invalid entries and dumps to the console the ownership information. To be able to access the host stage-2 page-tables from the kernel, a new hypervisor call was introduced which allows us to snapshot the page-tables in a host provided buffer. The hypervisor call is hidden behind CONFIG_NVHE_EL2_DEBUG as this should be used under debugging environment.
Link to the first version: https://lore.kernel.org/all/20230927112517.2631674-1-sebastianene@google.com/
Changelog: 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 (11): KVM: arm64: Add snap shooting the host stage-2 pagetables arm64: ptdump: Use the mask from the state structure arm64: ptdump: Add the walker function to the ptdump info structure KVM: arm64: Move pagetable definitions to common header arm64: ptdump: Introduce stage-2 pagetables format description arm64: ptdump: Add hooks on debugfs file operations arm64: ptdump: Register a debugfs entry for the host stage-2 page-tables arm64: ptdump: Parse the host stage-2 page-tables from the snapshot arm64: ptdump: Interpret memory attributes based on runtime configuration arm64: ptdump: Interpret pKVM ownership annotations arm64: ptdump: Add support for guest stage-2 pagetables dumping
arch/arm64/include/asm/kvm_asm.h | 1 + arch/arm64/include/asm/kvm_pgtable.h | 85 +++ arch/arm64/include/asm/ptdump.h | 27 +- arch/arm64/kvm/Kconfig | 12 + arch/arm64/kvm/hyp/include/nvhe/mem_protect.h | 8 +- arch/arm64/kvm/hyp/nvhe/hyp-main.c | 18 + arch/arm64/kvm/hyp/nvhe/mem_protect.c | 103 ++++ arch/arm64/kvm/hyp/pgtable.c | 98 ++-- arch/arm64/kvm/mmu.c | 3 + arch/arm64/mm/ptdump.c | 487 +++++++++++++++++- arch/arm64/mm/ptdump_debugfs.c | 42 +- 11 files changed, 822 insertions(+), 62 deletions(-)
-- 2.42.0.655.g421f12c284-goog
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