[v5,00/14] KVM: arm64: selftests: Introduce arch_timer selftest

Message

Raghavendra Rao Ananta Sept. 13, 2021, 8:49 p.m. UTC

Hello,

The patch series adds a KVM selftest to validate the behavior of
ARM's generic timer (patch-13). The test programs the timer IRQs
periodically, and for each interrupt, it validates the behaviour
against the architecture specifications. The test further provides
a command-line interface to configure the number of vCPUs, the
period of the timer, and the number of iterations that the test
has to run for.

Patch-14 adds an option to randomly migrate the vCPUs to different
physical CPUs across the system. The bug for the fix provided by
Marc with commit 3134cc8beb69d0d ("KVM: arm64: vgic: Resample HW
pending state on deactivation") was discovered using arch_timer
test with vCPU migrations.

Since the test heavily depends on interrupts, patch-12 adds a host
library to setup ARM Generic Interrupt Controller v3 (GICv3). This
includes creating a vGIC device, setting up distributor and
redistributor attributes, and mapping the guest physical addresses.
Symmetrical to this, patch-11 adds a guest library to talk to the vGIC,
which includes initializing the controller, enabling/disabling the
interrupts, and so on.

The following patches are utility patches that the above ones make use
of:
Patch-1 adds readl/writel support for guests to access MMIO space.

Patch-2 imports arch/arm64/include/asm/sysreg.h into
tools/arch/arm64/include/asm/ to make use of the register encodings
and read/write definitions.

Patch-3 is not directly related to the test, but makes
aarch64/debug-exceptions.c use the read/write definitions from the
imported sysreg.h and remove the existing definitions of read_sysreg()
and write_sysreg().

Patch-4 introduces ARM64_SYS_KVM_REG, that helps convert the SYS_*
register encodings in sysreg.h to be acceptable by get_reg() and set_reg().
It further replaces the users of ARM64_SYS_REG to use the new macro.

Patch-5 adds the support for cpu_relax().

Patch-6 adds basic arch_timer framework.

Patch-7 adds udelay() support for the guests to utilize.

Patch-8 adds local_irq_enable() and local_irq_disable() for the guests
to enable/disable interrupts.

Patch-9 adds the support to get the vcpuid for the guests. This allows
them to access any cpu-centric private data in the upcoming patches.

Patch-10 adds a light-weight support for spinlocks for the guests to
use.

The patch series, specifically the library support, is derived from the
kvm-unit-tests and the kernel itself.

Regards,
Raghavendra

v4 -> v5:

Addressed the comments by Andrew, Oliver, and Reiji (Thanks, again):
- Squashed patches 17/18 and 18/18 into 3/18 and 14/18, respectively.
- Dropped patches to keep track kvm_utils of nr_vcpus (12/18) and
  vm_get_mode() (13/18) as they were no longer needed.
- Instead of creating the a map, exporting the vcpuid to the guest
  is done by using the TPIDR_EL1 register.
- Just to be on the safer side, gic.c's gic_dist_init() explicitly
  checks if gic_ops is NULL.
- Move sysreg.h from within selftests to tool/arch/arm64/include/asm/.
- Rename ARM64_SYS_KVM_REG to KVM_ARM64_SYS_REG to improve readability.
- Use the GIC regions' sizes from asm/kvm.h instead of re-defining it
  in the vgic host support.
- Get the timer IRQ numbers via timer's device attributes
  (KVM_ARM_VCPU_TIMER_IRQ_PTIMER, KVM_ARM_VCPU_TIMER_IRQ_VTIMER) instead
  of depending on default numbers to be safe.
- Add check to see if the vCPU migrations are in fact enabled, before
  looking for at least two online physical CPUs for the test.
- Add missing blank lines in the arch_timer test.

v3 -> v4:

Addressed the comments by Andrew, Oliver, and Ricardo (Thank you):
- Reimplemented get_vcpuid() by exporting a map of vcpuid:mpidr to the
  guest.
- Import sysreg.h from arch/arm64/include/asm/sysreg.h to get the system
  register encodings and its read/write support. As a result, delete the
  existing definitions in processor.h.
- Introduce ARM64_SYS_KVM_REG that converts SYS_* register definitions
  from sysreg.h into the encodings accepted by get_reg() and set_reg().
- Hence, remove the existing encodings of system registers (CPACR_EL1,
  TCR_EL1, and friends) and replace all the its consumers throughout
  the selftests with ARM64_SYS_KVM_REG.
- Keep track of number of vCPUs in 'struct kvm_vm'.
- Add a helper method to get the KVM VM's mode.
- Modify the vGIC host function vgic_v3_setup to make use of the above
  two helper methods, which prevents it from accepting nr_vcpus as
  an argument.
- Move the definition of REDIST_REGION_ATTR_ADDR from lib/aarch64/vgic.c
  to include/aarch64/vgic.h.
- Make the selftest, vgic_init.c, use the definition of REDIST_REGION_ATTR_ADDR
  from include/aarch64/vgic.h.
- Turn ON vCPU migration by default (-m 2).
- Add pr_debug() to log vCPU migrations. Helpful for diagnosis.
- Change TEST_ASSERT(false,...) to TEST_FAIL() in the base arch_timer
  test.
- Include linux/types.h for __force definitions.
- Change the type of 'val' to 'int' in spin_lock() to match the lock
  value type.
- Fix typos in code files and comments.

v2 -> v3:

- Addressed the comments from Ricardo regarding moving the vGIC host
  support for selftests to its own library.
- Added an option (-m) to migrate the guest vCPUs to physical CPUs
  in the system.

v1 -> v2:

Addressed comments from Zenghui in include/aarch64/arch_timer.h:
- Correct the header description
- Remove unnecessary inclusion of linux/sizes.h
- Re-arrange CTL_ defines in ascending order
- Remove inappropriate 'return' from timer_set_* functions, which
  returns 'void'.

v1: https://lore.kernel.org/kvmarm/[e-mail]/
v2: https://lore.kernel.org/kvmarm/[e-mail]/
v3: https://lore.kernel.org/kvmarm/[e-mail]/
v4: https://lore.kernel.org/kvmarm/[e-mail]/

Raghavendra Rao Ananta (14):
  KVM: arm64: selftests: Add MMIO readl/writel support
  tools: arm64: Import sysreg.h
  KVM: arm64: selftests: Use read/write definitions from sysreg.h
  KVM: arm64: selftests: Introduce ARM64_SYS_KVM_REG
  KVM: arm64: selftests: Add support for cpu_relax
  KVM: arm64: selftests: Add basic support for arch_timers
  KVM: arm64: selftests: Add basic support to generate delays
  KVM: arm64: selftests: Add support to disable and enable local IRQs
  KVM: arm64: selftests: Add guest support to get the vcpuid
  KVM: arm64: selftests: Add light-weight spinlock support
  KVM: arm64: selftests: Add basic GICv3 support
  KVM: arm64: selftests: Add host support for vGIC
  KVM: arm64: selftests: Add arch_timer test
  KVM: arm64: selftests: arch_timer: Support vCPU migration

 tools/arch/arm64/include/asm/sysreg.h         | 1278 +++++++++++++++++
 tools/testing/selftests/kvm/.gitignore        |    1 +
 tools/testing/selftests/kvm/Makefile          |    3 +-
 .../selftests/kvm/aarch64/arch_timer.c        |  479 ++++++
 .../selftests/kvm/aarch64/debug-exceptions.c  |   30 +-
 .../selftests/kvm/aarch64/psci_cpu_on_test.c  |    2 +-
 .../testing/selftests/kvm/aarch64/vgic_init.c |    3 +-
 .../kvm/include/aarch64/arch_timer.h          |  142 ++
 .../selftests/kvm/include/aarch64/delay.h     |   25 +
 .../selftests/kvm/include/aarch64/gic.h       |   21 +
 .../selftests/kvm/include/aarch64/processor.h |   88 +-
 .../selftests/kvm/include/aarch64/spinlock.h  |   13 +
 .../selftests/kvm/include/aarch64/vgic.h      |   20 +
 .../testing/selftests/kvm/include/kvm_util.h  |    2 +
 tools/testing/selftests/kvm/lib/aarch64/gic.c |   95 ++
 .../selftests/kvm/lib/aarch64/gic_private.h   |   21 +
 .../selftests/kvm/lib/aarch64/gic_v3.c        |  240 ++++
 .../selftests/kvm/lib/aarch64/gic_v3.h        |   70 +
 .../selftests/kvm/lib/aarch64/processor.c     |   22 +-
 .../selftests/kvm/lib/aarch64/spinlock.c      |   27 +
 .../testing/selftests/kvm/lib/aarch64/vgic.c  |   70 +
 21 files changed, 2606 insertions(+), 46 deletions(-)
 create mode 100644 tools/arch/arm64/include/asm/sysreg.h
 create mode 100644 tools/testing/selftests/kvm/aarch64/arch_timer.c
 create mode 100644 tools/testing/selftests/kvm/include/aarch64/arch_timer.h
 create mode 100644 tools/testing/selftests/kvm/include/aarch64/delay.h
 create mode 100644 tools/testing/selftests/kvm/include/aarch64/gic.h
 create mode 100644 tools/testing/selftests/kvm/include/aarch64/spinlock.h
 create mode 100644 tools/testing/selftests/kvm/include/aarch64/vgic.h
 create mode 100644 tools/testing/selftests/kvm/lib/aarch64/gic.c
 create mode 100644 tools/testing/selftests/kvm/lib/aarch64/gic_private.h
 create mode 100644 tools/testing/selftests/kvm/lib/aarch64/gic_v3.c
 create mode 100644 tools/testing/selftests/kvm/lib/aarch64/gic_v3.h
 create mode 100644 tools/testing/selftests/kvm/lib/aarch64/spinlock.c
 create mode 100644 tools/testing/selftests/kvm/lib/aarch64/vgic.c