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[GIT,PULL] KVM/arm64 updates for 6.2

Message ID 20221205155845.233018-1-maz@kernel.org
State New
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Series [GIT,PULL] KVM/arm64 updates for 6.2 | expand

Pull-request

git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git tags/kvmarm-6.2

Message

Marc Zyngier Dec. 5, 2022, 3:58 p.m. UTC
Paolo,

Here's the meat of the KVM/arm64 updates for 6.2, and it is quite
packed with stuff (see the tag for the laundry list).

Things to notice:

- We have the usual shared branch with arm64, due to the never-ending
  sysreg repainting. I'm sure it will stop one day...

- There is a lot of selftest conflicts with your own branch, see:

  https://lore.kernel.org/r/20221201112432.4cb9ae42@canb.auug.org.au
  https://lore.kernel.org/r/20221201113626.438f13c5@canb.auug.org.au
  https://lore.kernel.org/r/20221201115741.7de32422@canb.auug.org.au
  https://lore.kernel.org/r/20221201120939.3c19f004@canb.auug.org.au
  https://lore.kernel.org/r/20221201131623.18ebc8d8@canb.auug.org.au

  for a rather exhaustive collection.

- For the 6.3 cycle, we are going to experiment with Oliver taking
  care of most of the patch herding. I'm sure he'll do a great job,
  but if there is the odd mistake, please cut him some slack and blame
  me instead.

Please pull,

	M.

The following changes since commit f0c4d9fc9cc9462659728d168387191387e903cc:

  Linux 6.1-rc4 (2022-11-06 15:07:11 -0800)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git tags/kvmarm-6.2

for you to fetch changes up to 753d734f3f347e7fc49b819472bbf61dcfc1a16f:

  Merge remote-tracking branch 'arm64/for-next/sysregs' into kvmarm-master/next (2022-12-05 14:39:53 +0000)

----------------------------------------------------------------
KVM/arm64 updates for 6.2

- Enable the per-vcpu dirty-ring tracking mechanism, together with an
  option to keep the good old dirty log around for pages that are
  dirtied by something other than a vcpu.

- Switch to the relaxed parallel fault handling, using RCU to delay
  page table reclaim and giving better performance under load.

- Relax the MTE ABI, allowing a VMM to use the MAP_SHARED mapping
  option, which multi-process VMMs such as crosvm rely on.

- Merge the pKVM shadow vcpu state tracking that allows the hypervisor
  to have its own view of a vcpu, keeping that state private.

- Add support for the PMUv3p5 architecture revision, bringing support
  for 64bit counters on systems that support it, and fix the
  no-quite-compliant CHAIN-ed counter support for the machines that
  actually exist out there.

- Fix a handful of minor issues around 52bit VA/PA support (64kB pages
  only) as a prefix of the oncoming support for 4kB and 16kB pages.

- Add/Enable/Fix a bunch of selftests covering memslots, breakpoints,
  stage-2 faults and access tracking. You name it, we got it, we
  probably broke it.

- Pick a small set of documentation and spelling fixes, because no
  good merge window would be complete without those.

As a side effect, this tag also drags:

- The 'kvmarm-fixes-6.1-3' tag as a dependency to the dirty-ring
  series

- A shared branch with the arm64 tree that repaints all the system
  registers to match the ARM ARM's naming, and resulting in
  interesting conflicts

----------------------------------------------------------------
Anshuman Khandual (1):
      KVM: arm64: PMU: Replace version number '0' with ID_AA64DFR0_EL1_PMUVer_NI

Catalin Marinas (4):
      mm: Do not enable PG_arch_2 for all 64-bit architectures
      arm64: mte: Fix/clarify the PG_mte_tagged semantics
      KVM: arm64: Simplify the sanitise_mte_tags() logic
      arm64: mte: Lock a page for MTE tag initialisation

Fuad Tabba (3):
      KVM: arm64: Add hyp_spinlock_t static initializer
      KVM: arm64: Add infrastructure to create and track pKVM instances at EL2
      KVM: arm64: Instantiate pKVM hypervisor VM and vCPU structures from EL1

Gavin Shan (14):
      KVM: x86: Introduce KVM_REQ_DIRTY_RING_SOFT_FULL
      KVM: Move declaration of kvm_cpu_dirty_log_size() to kvm_dirty_ring.h
      KVM: Support dirty ring in conjunction with bitmap
      KVM: arm64: Enable ring-based dirty memory tracking
      KVM: selftests: Use host page size to map ring buffer in dirty_log_test
      KVM: selftests: Clear dirty ring states between two modes in dirty_log_test
      KVM: selftests: Automate choosing dirty ring size in dirty_log_test
      KVM: selftests: memslot_perf_test: Use data->nslots in prepare_vm()
      KVM: selftests: memslot_perf_test: Consolidate loop conditions in prepare_vm()
      KVM: selftests: memslot_perf_test: Probe memory slots for once
      KVM: selftests: memslot_perf_test: Support variable guest page size
      KVM: selftests: memslot_perf_test: Consolidate memory
      KVM: selftests: memslot_perf_test: Report optimal memory slots
      KVM: Push dirty information unconditionally to backup bitmap

James Morse (38):
      arm64/sysreg: Standardise naming for ID_MMFR0_EL1
      arm64/sysreg: Standardise naming for ID_MMFR4_EL1
      arm64/sysreg: Standardise naming for ID_MMFR5_EL1
      arm64/sysreg: Standardise naming for ID_ISAR0_EL1
      arm64/sysreg: Standardise naming for ID_ISAR4_EL1
      arm64/sysreg: Standardise naming for ID_ISAR5_EL1
      arm64/sysreg: Standardise naming for ID_ISAR6_EL1
      arm64/sysreg: Standardise naming for ID_PFR0_EL1
      arm64/sysreg: Standardise naming for ID_PFR1_EL1
      arm64/sysreg: Standardise naming for ID_PFR2_EL1
      arm64/sysreg: Standardise naming for ID_DFR0_EL1
      arm64/sysreg: Standardise naming for ID_DFR1_EL1
      arm64/sysreg: Standardise naming for MVFR0_EL1
      arm64/sysreg: Standardise naming for MVFR1_EL1
      arm64/sysreg: Standardise naming for MVFR2_EL1
      arm64/sysreg: Extend the maximum width of a register and symbol name
      arm64/sysreg: Convert ID_MMFR0_EL1 to automatic generation
      arm64/sysreg: Convert ID_MMFR1_EL1 to automatic generation
      arm64/sysreg: Convert ID_MMFR2_EL1 to automatic generation
      arm64/sysreg: Convert ID_MMFR3_EL1 to automatic generation
      arm64/sysreg: Convert ID_MMFR4_EL1 to automatic generation
      arm64/sysreg: Convert ID_ISAR0_EL1 to automatic generation
      arm64/sysreg: Convert ID_ISAR1_EL1 to automatic generation
      arm64/sysreg: Convert ID_ISAR2_EL1 to automatic generation
      arm64/sysreg: Convert ID_ISAR3_EL1 to automatic generation
      arm64/sysreg: Convert ID_ISAR4_EL1 to automatic generation
      arm64/sysreg: Convert ID_ISAR5_EL1 to automatic generation
      arm64/sysreg: Convert ID_ISAR6_EL1 to automatic generation
      arm64/sysreg: Convert ID_PFR0_EL1 to automatic generation
      arm64/sysreg: Convert ID_PFR1_EL1 to automatic generation
      arm64/sysreg: Convert ID_PFR2_EL1 to automatic generation
      arm64/sysreg: Convert MVFR0_EL1 to automatic generation
      arm64/sysreg: Convert MVFR1_EL1 to automatic generation
      arm64/sysreg: Convert MVFR2_EL1 to automatic generation
      arm64/sysreg: Convert ID_MMFR5_EL1 to automatic generation
      arm64/sysreg: Convert ID_AFR0_EL1 to automatic generation
      arm64/sysreg: Convert ID_DFR0_EL1 to automatic generation
      arm64/sysreg: Convert ID_DFR1_EL1 to automatic generation

Marc Zyngier (32):
      Merge tag 'kvmarm-fixes-6.1-3' into kvm-arm64/dirty-ring
      arm64: Add ID_DFR0_EL1.PerfMon values for PMUv3p7 and IMP_DEF
      KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode
      KVM: arm64: PMU: Always advertise the CHAIN event
      KVM: arm64: PMU: Distinguish between 64bit counter and 64bit overflow
      KVM: arm64: PMU: Narrow the overflow checking when required
      KVM: arm64: PMU: Only narrow counters that are not 64bit wide
      KVM: arm64: PMU: Add counter_index_to_*reg() helpers
      KVM: arm64: PMU: Simplify setting a counter to a specific value
      KVM: arm64: PMU: Do not let AArch32 change the counters' top 32 bits
      KVM: arm64: PMU: Move the ID_AA64DFR0_EL1.PMUver limit to VM creation
      KVM: arm64: PMU: Allow ID_AA64DFR0_EL1.PMUver to be set from userspace
      KVM: arm64: PMU: Allow ID_DFR0_EL1.PerfMon to be set from userspace
      KVM: arm64: PMU: Implement PMUv3p5 long counter support
      KVM: arm64: PMU: Allow PMUv3p5 to be exposed to the guest
      KVM: arm64: PMU: Simplify vcpu computation on perf overflow notification
      KVM: arm64: PMU: Make kvm_pmc the main data structure
      KVM: arm64: PMU: Simplify PMCR_EL0 reset handling
      KVM: arm64: PMU: Sanitise PMCR_EL0.LP on first vcpu run
      KVM: arm64: PMU: Fix period computation for 64bit counters with 32bit overflow
      Merge branch kvm-arm64/selftest/memslot-fixes into kvmarm-master/next
      Merge branch kvm-arm64/selftest/linked-bps into kvmarm-master/next
      Merge branch kvm-arm64/selftest/s2-faults into kvmarm-master/next
      Merge branch kvm-arm64/selftest/access-tracking into kvmarm-master/next
      Merge branch kvm-arm64/52bit-fixes into kvmarm-master/next
      Merge branch kvm-arm64/dirty-ring into kvmarm-master/next
      Merge branch kvm-arm64/parallel-faults into kvmarm-master/next
      Merge branch kvm-arm64/pkvm-vcpu-state into kvmarm-master/next
      Merge branch kvm-arm64/mte-map-shared into kvmarm-master/next
      Merge branch kvm-arm64/pmu-unchained into kvmarm-master/next
      Merge branch kvm-arm64/misc-6.2 into kvmarm-master/next
      Merge remote-tracking branch 'arm64/for-next/sysregs' into kvmarm-master/next

Oliver Upton (19):
      KVM: arm64: Combine visitor arguments into a context structure
      KVM: arm64: Stash observed pte value in visitor context
      KVM: arm64: Pass mm_ops through the visitor context
      KVM: arm64: Don't pass kvm_pgtable through kvm_pgtable_walk_data
      KVM: arm64: Add a helper to tear down unlinked stage-2 subtrees
      KVM: arm64: Use an opaque type for pteps
      KVM: arm64: Tear down unlinked stage-2 subtree after break-before-make
      KVM: arm64: Protect stage-2 traversal with RCU
      KVM: arm64: Atomically update stage 2 leaf attributes in parallel walks
      KVM: arm64: Split init and set for table PTE
      KVM: arm64: Make block->table PTE changes parallel-aware
      KVM: arm64: Make leaf->leaf PTE changes parallel-aware
      KVM: arm64: Make table->block changes parallel-aware
      KVM: arm64: Handle stage-2 faults in parallel
      KVM: arm64: Take a pointer to walker data in kvm_dereference_pteref()
      KVM: arm64: Don't acquire RCU read lock for exclusive table walks
      KVM: arm64: Reject shared table walks in the hyp code
      KVM: selftests: Have perf_test_util signal when to stop vCPUs
      KVM: selftests: Build access_tracking_perf_test for arm64

Peter Collingbourne (4):
      mm: Add PG_arch_3 page flag
      KVM: arm64: unify the tests for VMAs in memslots when MTE is enabled
      KVM: arm64: permit all VM_MTE_ALLOWED mappings with MTE enabled
      Documentation: document the ABI changes for KVM_CAP_ARM_MTE

Quentin Perret (14):
      KVM: arm64: Move hyp refcount manipulation helpers to common header file
      KVM: arm64: Allow attaching of non-coalescable pages to a hyp pool
      KVM: arm64: Back the hypervisor 'struct hyp_page' array for all memory
      KVM: arm64: Fix-up hyp stage-1 refcounts for all pages mapped at EL2
      KVM: arm64: Prevent the donation of no-map pages
      KVM: arm64: Add helpers to pin memory shared with the hypervisor at EL2
      KVM: arm64: Add per-cpu fixmap infrastructure at EL2
      KVM: arm64: Add generic hyp_memcache helpers
      KVM: arm64: Consolidate stage-2 initialisation into a single function
      KVM: arm64: Instantiate guest stage-2 page-tables at EL2
      KVM: arm64: Return guest memory from EL2 via dedicated teardown memcache
      KVM: arm64: Unmap 'kvm_arm_hyp_percpu_base' from the host
      KVM: arm64: Explicitly map 'kvm_vgic_global_state' at EL2
      KVM: arm64: Don't unnecessarily map host kernel sections at EL2

Reiji Watanabe (9):
      KVM: arm64: selftests: Use FIELD_GET() to extract ID register fields
      KVM: arm64: selftests: Add write_dbg{b,w}{c,v}r helpers in debug-exceptions
      KVM: arm64: selftests: Remove the hard-coded {b,w}pn#0 from debug-exceptions
      KVM: arm64: selftests: Add helpers to enable debug exceptions
      KVM: arm64: selftests: Stop unnecessary test stage tracking of debug-exceptions
      KVM: arm64: selftests: Change debug_version() to take ID_AA64DFR0_EL1
      KVM: arm64: selftests: Add a test case for a linked breakpoint
      KVM: arm64: selftests: Add a test case for a linked watchpoint
      KVM: arm64: selftests: Test with every breakpoint/watchpoint

Ricardo Koller (14):
      KVM: selftests: Add a userfaultfd library
      KVM: selftests: aarch64: Add virt_get_pte_hva() library function
      KVM: selftests: Add missing close and munmap in __vm_mem_region_delete()
      KVM: selftests: aarch64: Construct DEFAULT_MAIR_EL1 using sysreg.h macros
      tools: Copy bitfield.h from the kernel sources
      KVM: selftests: Stash backing_src_type in struct userspace_mem_region
      KVM: selftests: Add vm->memslots[] and enum kvm_mem_region_type
      KVM: selftests: Fix alignment in virt_arch_pgd_alloc() and vm_vaddr_alloc()
      KVM: selftests: Use the right memslot for code, page-tables, and data allocations
      KVM: selftests: aarch64: Add aarch64/page_fault_test
      KVM: selftests: aarch64: Add userfaultfd tests into page_fault_test
      KVM: selftests: aarch64: Add dirty logging tests into page_fault_test
      KVM: selftests: aarch64: Add readonly memslot tests into page_fault_test
      KVM: selftests: aarch64: Add mix of tests into page_fault_test

Ryan Roberts (3):
      KVM: arm64: Fix kvm init failure when mode!=vhe and VA_BITS=52.
      KVM: arm64: Fix PAR_TO_HPFAR() to work independently of PA_BITS.
      KVM: arm64: Fix benign bug with incorrect use of VA_BITS

Usama Arif (1):
      KVM: arm64: Fix pvtime documentation

Will Deacon (9):
      KVM: arm64: Unify identifiers used to distinguish host and hypervisor
      KVM: arm64: Implement do_donate() helper for donating memory
      KVM: arm64: Include asm/kvm_mmu.h in nvhe/mem_protect.h
      KVM: arm64: Rename 'host_kvm' to 'host_mmu'
      KVM: arm64: Initialise hypervisor copies of host symbols unconditionally
      KVM: arm64: Provide I-cache invalidation by virtual address at EL2
      KVM: arm64: Maintain a copy of 'kvm_arm_vmid_bits' at EL2
      KVM: arm64: Use the pKVM hyp vCPU structure in handle___kvm_vcpu_run()
      arm64/sysreg: Remove duplicate definitions from asm/sysreg.h

Zhiyuan Dai (1):
      KVM: arm64: Fix typo in comment

 Documentation/virt/kvm/api.rst                     |   41 +-
 Documentation/virt/kvm/arm/pvtime.rst              |   14 +-
 Documentation/virt/kvm/devices/arm-vgic-its.rst    |    5 +-
 Documentation/virt/kvm/devices/vcpu.rst            |    2 +
 arch/arm64/Kconfig                                 |    1 +
 arch/arm64/include/asm/kvm_arm.h                   |    8 +-
 arch/arm64/include/asm/kvm_asm.h                   |    7 +-
 arch/arm64/include/asm/kvm_host.h                  |   76 +-
 arch/arm64/include/asm/kvm_hyp.h                   |    3 +
 arch/arm64/include/asm/kvm_mmu.h                   |    2 +-
 arch/arm64/include/asm/kvm_pgtable.h               |  175 ++-
 arch/arm64/include/asm/kvm_pkvm.h                  |   38 +
 arch/arm64/include/asm/mte.h                       |   65 +-
 arch/arm64/include/asm/pgtable.h                   |    4 +-
 arch/arm64/include/asm/sysreg.h                    |  138 ---
 arch/arm64/include/uapi/asm/kvm.h                  |    1 +
 arch/arm64/kernel/cpufeature.c                     |  212 ++--
 arch/arm64/kernel/elfcore.c                        |    2 +-
 arch/arm64/kernel/hibernate.c                      |    2 +-
 arch/arm64/kernel/image-vars.h                     |   15 -
 arch/arm64/kernel/mte.c                            |   21 +-
 arch/arm64/kvm/Kconfig                             |    2 +
 arch/arm64/kvm/arm.c                               |   90 +-
 arch/arm64/kvm/guest.c                             |   18 +-
 arch/arm64/kvm/hyp/hyp-constants.c                 |    3 +
 arch/arm64/kvm/hyp/include/nvhe/mem_protect.h      |   25 +-
 arch/arm64/kvm/hyp/include/nvhe/memory.h           |   27 +
 arch/arm64/kvm/hyp/include/nvhe/mm.h               |   18 +-
 arch/arm64/kvm/hyp/include/nvhe/pkvm.h             |   68 ++
 arch/arm64/kvm/hyp/include/nvhe/spinlock.h         |   10 +-
 arch/arm64/kvm/hyp/nvhe/cache.S                    |   11 +
 arch/arm64/kvm/hyp/nvhe/hyp-main.c                 |  110 +-
 arch/arm64/kvm/hyp/nvhe/hyp-smp.c                  |    2 +
 arch/arm64/kvm/hyp/nvhe/mem_protect.c              |  521 ++++++++-
 arch/arm64/kvm/hyp/nvhe/mm.c                       |  167 ++-
 arch/arm64/kvm/hyp/nvhe/page_alloc.c               |   29 +-
 arch/arm64/kvm/hyp/nvhe/pkvm.c                     |  436 ++++++++
 arch/arm64/kvm/hyp/nvhe/setup.c                    |   98 +-
 arch/arm64/kvm/hyp/pgtable.c                       |  652 ++++++------
 arch/arm64/kvm/hyp/vhe/Makefile                    |    2 +-
 arch/arm64/kvm/mmu.c                               |  193 ++--
 arch/arm64/kvm/pkvm.c                              |  138 ++-
 arch/arm64/kvm/pmu-emul.c                          |  482 ++++-----
 arch/arm64/kvm/reset.c                             |   29 -
 arch/arm64/kvm/sys_regs.c                          |  157 ++-
 arch/arm64/kvm/vgic/vgic-its.c                     |   20 +
 arch/arm64/lib/mte.S                               |    2 +-
 arch/arm64/mm/copypage.c                           |    7 +-
 arch/arm64/mm/fault.c                              |    4 +-
 arch/arm64/mm/mteswap.c                            |   16 +-
 arch/arm64/tools/gen-sysreg.awk                    |    2 +-
 arch/arm64/tools/sysreg                            |  754 +++++++++++++
 arch/x86/include/asm/kvm_host.h                    |    2 -
 arch/x86/kvm/x86.c                                 |   15 +-
 fs/proc/page.c                                     |    3 +-
 include/kvm/arm_pmu.h                              |   15 +-
 include/kvm/arm_vgic.h                             |    1 +
 include/linux/kernel-page-flags.h                  |    1 +
 include/linux/kvm_dirty_ring.h                     |   20 +-
 include/linux/kvm_host.h                           |   10 +-
 include/linux/page-flags.h                         |    3 +-
 include/trace/events/mmflags.h                     |    9 +-
 include/uapi/linux/kvm.h                           |    1 +
 mm/Kconfig                                         |    8 +
 mm/huge_memory.c                                   |    3 +-
 tools/include/linux/bitfield.h                     |  176 ++++
 tools/testing/selftests/kvm/.gitignore             |    1 +
 tools/testing/selftests/kvm/Makefile               |    3 +
 .../selftests/kvm/aarch64/aarch32_id_regs.c        |    3 +-
 .../selftests/kvm/aarch64/debug-exceptions.c       |  311 ++++--
 .../selftests/kvm/aarch64/page_fault_test.c        | 1112 ++++++++++++++++++++
 .../selftests/kvm/access_tracking_perf_test.c      |    8 +-
 tools/testing/selftests/kvm/demand_paging_test.c   |  228 +---
 tools/testing/selftests/kvm/dirty_log_test.c       |   53 +-
 .../selftests/kvm/include/aarch64/processor.h      |   35 +-
 .../testing/selftests/kvm/include/kvm_util_base.h  |   31 +-
 .../testing/selftests/kvm/include/perf_test_util.h |    3 +
 .../selftests/kvm/include/userfaultfd_util.h       |   45 +
 .../testing/selftests/kvm/lib/aarch64/processor.c  |   55 +-
 tools/testing/selftests/kvm/lib/elf.c              |    3 +-
 tools/testing/selftests/kvm/lib/kvm_util.c         |   84 +-
 tools/testing/selftests/kvm/lib/perf_test_util.c   |    3 +
 tools/testing/selftests/kvm/lib/riscv/processor.c  |   29 +-
 tools/testing/selftests/kvm/lib/s390x/processor.c  |    8 +-
 tools/testing/selftests/kvm/lib/userfaultfd_util.c |  186 ++++
 tools/testing/selftests/kvm/lib/x86_64/processor.c |   13 +-
 .../kvm/memslot_modification_stress_test.c         |    6 +-
 tools/testing/selftests/kvm/memslot_perf_test.c    |  317 ++++--
 virt/kvm/Kconfig                                   |    6 +
 virt/kvm/dirty_ring.c                              |   46 +-
 virt/kvm/kvm_main.c                                |   65 +-
 91 files changed, 6073 insertions(+), 1773 deletions(-)
 create mode 100644 arch/arm64/kvm/hyp/include/nvhe/pkvm.h
 create mode 100644 tools/include/linux/bitfield.h
 create mode 100644 tools/testing/selftests/kvm/aarch64/page_fault_test.c
 create mode 100644 tools/testing/selftests/kvm/include/userfaultfd_util.h
 create mode 100644 tools/testing/selftests/kvm/lib/userfaultfd_util.c

Comments

Sean Christopherson Dec. 6, 2022, 6:10 p.m. UTC | #1
On Tue, Dec 06, 2022, Paolo Bonzini wrote:
> On 12/5/22 16:58, Marc Zyngier wrote:
> > - There is a lot of selftest conflicts with your own branch, see:
> > 
> >    https://lore.kernel.org/r/20221201112432.4cb9ae42@canb.auug.org.au
> >    https://lore.kernel.org/r/20221201113626.438f13c5@canb.auug.org.au
> >    https://lore.kernel.org/r/20221201115741.7de32422@canb.auug.org.au
> >    https://lore.kernel.org/r/20221201120939.3c19f004@canb.auug.org.au
> >    https://lore.kernel.org/r/20221201131623.18ebc8d8@canb.auug.org.au
> > 
> >    for a rather exhaustive collection.
> 
> Yeah, I saw them in Stephen's messages but missed your reply.
> 
> In retrospect, at least Gavin's series for memslot_perf_test should have
> been applied by both of us with a topic branch, but there's so many
> conflicts all over the place that it's hard to single out one series.
> It just happens.

Alternatively, we could have a dedicated selftests/kvm tree (or branch)?

I almost suggested doing that on multiple occasions this cycle, but ultimately
decided not to because it would effectively mean splitting series that touch KVM
and selftests into different trees, which would create a different kind of
dependency hell.  Or maybe a hybrid approach where series that only (or mostly?)
touch selftests go into a dedicated tree?

I get the feeling that I'm overthinking things though, this level of activity and
conflicts should be relatively rare.
Mark Brown Dec. 6, 2022, 6:20 p.m. UTC | #2
On Tue, Dec 06, 2022 at 06:10:32PM +0000, Sean Christopherson wrote:

> Alternatively, we could have a dedicated selftests/kvm tree (or branch)?

> I almost suggested doing that on multiple occasions this cycle, but ultimately
> decided not to because it would effectively mean splitting series that touch KVM
> and selftests into different trees, which would create a different kind of
> dependency hell.  Or maybe a hybrid approach where series that only (or mostly?)
> touch selftests go into a dedicated tree?

Some other subsystems do have a separate branch for kselftests.  One
fairly common occurrence is that the selftests branch ends up failing to
build independently because someone adds new ABI together with a
selftest but the patches adding the ABI don't end up on the same branch
as the tests which try to use them.  That is of course resolvable but
it's a common friction point.
Marc Zyngier Dec. 6, 2022, 7:27 p.m. UTC | #3
On Tue, 06 Dec 2022 17:41:21 +0000,
Paolo Bonzini <pbonzini@redhat.com> wrote:
> 
> On 12/5/22 16:58, Marc Zyngier wrote:
> > - There is a lot of selftest conflicts with your own branch, see:
> > 
> >    https://lore.kernel.org/r/20221201112432.4cb9ae42@canb.auug.org.au
> >    https://lore.kernel.org/r/20221201113626.438f13c5@canb.auug.org.au
> >    https://lore.kernel.org/r/20221201115741.7de32422@canb.auug.org.au
> >    https://lore.kernel.org/r/20221201120939.3c19f004@canb.auug.org.au
> >    https://lore.kernel.org/r/20221201131623.18ebc8d8@canb.auug.org.au
> > 
> >    for a rather exhaustive collection.
> 
> Yeah, I saw them in Stephen's messages but missed your reply.
> 
> In retrospect, at least Gavin's series for memslot_perf_test should have
> been applied by both of us with a topic branch, but there's so many
> conflicts all over the place that it's hard to single out one series.
> It just happens.

I generally queue things on topic branches for my own sanity, happy to
make them available in the future.

> 
> The only conflict in non-x86 code is the following one, please check
> if I got it right.
> 
> diff --git a/tools/testing/selftests/kvm/aarch64/page_fault_test.c b/tools/testing/selftests/kvm/aarch64/page_fault_test.c
> index 05bb6a6369c2..0cda70bef5d5 100644
> --- a/tools/testing/selftests/kvm/aarch64/page_fault_test.c
> +++ b/tools/testing/selftests/kvm/aarch64/page_fault_test.c
> @@ -609,6 +609,8 @@ static void setup_memslots(struct kvm_vm *vm, struct test_params *p)
>  				    data_size / guest_page_size,
>  				    p->test_desc->data_memslot_flags);
>  	vm->memslots[MEM_REGION_TEST_DATA] = TEST_DATA_MEMSLOT;
> +
> +	ucall_init(vm, data_gpa + data_size);
>  }
>   static void setup_default_handlers(struct test_desc *test)
> @@ -704,8 +706,6 @@ static void run_test(enum vm_guest_mode mode, void *arg)
>   	setup_gva_maps(vm);
>  -	ucall_init(vm, NULL);
> -
>  	reset_event_counts();
>   	/*
> 
> 
> Special care is needed here because the test uses ____vm_create().
> 
> I haven't pushed to kvm/next yet to give you time to check, so the
> merge is currently in kvm/queue only.

There has been a couple of -next failures reported by broonie:

https://lore.kernel.org/r/20221206175916.250104-1-broonie@kernel.org
https://lore.kernel.org/r/20221206181506.252537-1-broonie@kernel.org

which I think you've received as well. The second patch is definitely
needed, but you've already solved the first one. At least things do
build.

> 
> > - For the 6.3 cycle, we are going to experiment with Oliver taking
> >    care of most of the patch herding. I'm sure he'll do a great job,
> >    but if there is the odd mistake, please cut him some slack and blame
> >    me instead.
> 
> Absolutely - you both have all the slack you need, synchronization
> is harder than it seems.

Thanks,

	M.
Paolo Bonzini Dec. 6, 2022, 9:43 p.m. UTC | #4
On 12/6/22 19:20, Mark Brown wrote:
>> I almost suggested doing that on multiple occasions this cycle, but ultimately
>> decided not to because it would effectively mean splitting series that touch KVM
>> and selftests into different trees, which would create a different kind of
>> dependency hell.  Or maybe a hybrid approach where series that only (or mostly?)
>> touch selftests go into a dedicated tree?
>
> Some other subsystems do have a separate branch for kselftests.  One
> fairly common occurrence is that the selftests branch ends up failing to
> build independently because someone adds new ABI together with a
> selftest but the patches adding the ABI don't end up on the same branch
> as the tests which try to use them.  That is of course resolvable but
> it's a common friction point.

Yeah, the right solution is simply to merge selftests changes separately 
from the rest and use topic branches.

We will have more friction of this kind if we succeed in making more KVM 
code multi-architecture, so let's just treat selftests as the more 
innocuous drill...

Paolo
Marc Zyngier Dec. 7, 2022, 7:49 a.m. UTC | #5
On Tue, 06 Dec 2022 21:43:43 +0000,
Paolo Bonzini <pbonzini@redhat.com> wrote:
> 
> On 12/6/22 19:20, Mark Brown wrote:
> >> I almost suggested doing that on multiple occasions this cycle, but ultimately
> >> decided not to because it would effectively mean splitting series that touch KVM
> >> and selftests into different trees, which would create a different kind of
> >> dependency hell.  Or maybe a hybrid approach where series that only (or mostly?)
> >> touch selftests go into a dedicated tree?
> > 
> > Some other subsystems do have a separate branch for kselftests.  One
> > fairly common occurrence is that the selftests branch ends up failing to
> > build independently because someone adds new ABI together with a
> > selftest but the patches adding the ABI don't end up on the same branch
> > as the tests which try to use them.  That is of course resolvable but
> > it's a common friction point.
> 
> Yeah, the right solution is simply to merge selftests changes
> separately from the rest and use topic branches.

Don't know if this is what you have in mind, but I think that we
should use topic branches for *everything*. The only things for which
I don't use a separate branch are the odd drive-by patches, of the
spelling fix persuasion.

That's what we do for arm64 and the IRQ subsystem. It is a bit more
involved at queuing time, but makes dropping series from -next
extremely easy, without affecting the history. And crucially, it gives
everyone a hint to base their stuff on a stable commit, not a random
"tip of kvm/queue as of three days ago".

	M.
Oliver Upton Dec. 7, 2022, 9:51 p.m. UTC | #6
On Tue, Dec 06, 2022 at 06:41:21PM +0100, Paolo Bonzini wrote:
> On 12/5/22 16:58, Marc Zyngier wrote:
> > - There is a lot of selftest conflicts with your own branch, see:
> > 
> >    https://lore.kernel.org/r/20221201112432.4cb9ae42@canb.auug.org.au
> >    https://lore.kernel.org/r/20221201113626.438f13c5@canb.auug.org.au
> >    https://lore.kernel.org/r/20221201115741.7de32422@canb.auug.org.au
> >    https://lore.kernel.org/r/20221201120939.3c19f004@canb.auug.org.au
> >    https://lore.kernel.org/r/20221201131623.18ebc8d8@canb.auug.org.au
> > 
> >    for a rather exhaustive collection.
> 
> Yeah, I saw them in Stephen's messages but missed your reply.
> 
> In retrospect, at least Gavin's series for memslot_perf_test should have
> been applied by both of us with a topic branch, but there's so many
> conflicts all over the place that it's hard to single out one series.
> It just happens.
> 
> The only conflict in non-x86 code is the following one, please check
> if I got it right.
> 
> diff --git a/tools/testing/selftests/kvm/aarch64/page_fault_test.c b/tools/testing/selftests/kvm/aarch64/page_fault_test.c
> index 05bb6a6369c2..0cda70bef5d5 100644
> --- a/tools/testing/selftests/kvm/aarch64/page_fault_test.c
> +++ b/tools/testing/selftests/kvm/aarch64/page_fault_test.c
> @@ -609,6 +609,8 @@ static void setup_memslots(struct kvm_vm *vm, struct test_params *p)
>  				    data_size / guest_page_size,
>  				    p->test_desc->data_memslot_flags);
>  	vm->memslots[MEM_REGION_TEST_DATA] = TEST_DATA_MEMSLOT;
> +
> +	ucall_init(vm, data_gpa + data_size);
>  }
>  static void setup_default_handlers(struct test_desc *test)
> @@ -704,8 +706,6 @@ static void run_test(enum vm_guest_mode mode, void *arg)
>  	setup_gva_maps(vm);
> -	ucall_init(vm, NULL);
> -
>  	reset_event_counts();
>  	/*
> 
> 
> Special care is needed here because the test uses ____vm_create().
> 
> I haven't pushed to kvm/next yet to give you time to check, so the
> merge is currently in kvm/queue only.

Have a look at this series, which gets things building and actually
passing again:

https://lore.kernel.org/kvm/20221207214809.489070-1-oliver.upton@linux.dev/

> > - For the 6.3 cycle, we are going to experiment with Oliver taking
> >    care of most of the patch herding. I'm sure he'll do a great job,
> >    but if there is the odd mistake, please cut him some slack and blame
> >    me instead.
> 
> Absolutely - you both have all the slack you need, synchronization
> is harder than it seems.

Appreciated!

--
Thanks,
Oliver
Paolo Bonzini Dec. 9, 2022, 8:08 a.m. UTC | #7
On 12/7/22 08:49, Marc Zyngier wrote:
> On Tue, 06 Dec 2022 21:43:43 +0000,
> Paolo Bonzini <pbonzini@redhat.com> wrote:
>>
>> On 12/6/22 19:20, Mark Brown wrote:
>>>> I almost suggested doing that on multiple occasions this cycle, but ultimately
>>>> decided not to because it would effectively mean splitting series that touch KVM
>>>> and selftests into different trees, which would create a different kind of
>>>> dependency hell.  Or maybe a hybrid approach where series that only (or mostly?)
>>>> touch selftests go into a dedicated tree?
>>>
>>> Some other subsystems do have a separate branch for kselftests.  One
>>> fairly common occurrence is that the selftests branch ends up failing to
>>> build independently because someone adds new ABI together with a
>>> selftest but the patches adding the ABI don't end up on the same branch
>>> as the tests which try to use them.  That is of course resolvable but
>>> it's a common friction point.
>>
>> Yeah, the right solution is simply to merge selftests changes
>> separately from the rest and use topic branches.
> 
> Don't know if this is what you have in mind, but I think that we
> should use topic branches for *everything*. The only things for which
> I don't use a separate branch are the odd drive-by patches, of the
> spelling fix persuasion.

Yeah, I just wish we had better tools to manage them...

Paolo

> That's what we do for arm64 and the IRQ subsystem. It is a bit more
> involved at queuing time, but makes dropping series from -next
> extremely easy, without affecting the history. And crucially, it gives
> everyone a hint to base their stuff on a stable commit, not a random
> "tip of kvm/queue as of three days ago".
> 
> 	M.
>
Paolo Bonzini Dec. 9, 2022, 4:56 p.m. UTC | #8
On 12/7/22 22:51, Oliver Upton wrote:
>>
>> I haven't pushed to kvm/next yet to give you time to check, so the
>> merge is currently in kvm/queue only.
> Have a look at this series, which gets things building and actually
> passing again:
> 
> https://lore.kernel.org/kvm/20221207214809.489070-1-oliver.upton@linux.dev/

Thank you!  Squashed 1-2 and applied 3-4.

Paolo
Oliver Upton Dec. 9, 2022, 5:05 p.m. UTC | #9
Hey Paolo,

On Fri, Dec 09, 2022 at 05:56:50PM +0100, Paolo Bonzini wrote:
> On 12/7/22 22:51, Oliver Upton wrote:
> > > 
> > > I haven't pushed to kvm/next yet to give you time to check, so the
> > > merge is currently in kvm/queue only.
> > Have a look at this series, which gets things building and actually
> > passing again:
> > 
> > https://lore.kernel.org/kvm/20221207214809.489070-1-oliver.upton@linux.dev/
> 
> Thank you!  Squashed 1-2 and applied 3-4.

I actually wound up sending a v2 for this :)

1-2 are the same, but I addressed some of Sean's feedback and also
pulled in more fixes. In addition to the problems with page_fault_test,
other KVM selftests were magically failing on arm64 because identity
mapping ucall MMIO punched a hole straight through the program image.

Mind dumping what I had in v1 and applying this instead?

https://lore.kernel.org/kvm/20221209015307.1781352-1-oliver.upton@linux.dev/

Thanks!

--
Best,
Oliver
Paolo Bonzini Dec. 9, 2022, 5:07 p.m. UTC | #10
On Fri, Dec 9, 2022 at 6:05 PM Oliver Upton <oliver.upton@linux.dev> wrote:
> Mind dumping what I had in v1 and applying this instead?
>
> https://lore.kernel.org/kvm/20221209015307.1781352-1-oliver.upton@linux.dev/

Ouch, five minutes too late... I can take care of the difference but
it'll have to wait for Monday.

Paolo