The PSCI v1.0 specification describes a call, SYSTEM_SUSPEND, which
allows software to request that the system be placed into the lowest
possible power state and await a wakeup event. This call is optional
in v1.0 and v1.1. KVM does not currently support this optional call.
This series adds support for the PSCI SYSTEM_SUSPEND call to KVM/arm64.
For reasons best described in patch 8, it is infeasible to correctly
implement PSCI SYSTEM_SUSPEND (or any system-wide event for that matter)
in a split design between kernel/userspace. As such, this series cheaply
exits to userspace so it can decide what to do with the call. This
series also gives userspace some help to emulate suspension with a new
MP state that awaits an unmasked pending interrupt.
Patches 1-6 are small reworks to more easily shoehorn the new features
into the kernel.
Patch 7 stands up the new suspend MP state, allowing userspace to
emulate the PSCI call.
Patch 8 actually allows userspace to enable the PSCI call, which
requires explicit opt-in for the new KVM_EXIT_SYSTEM_EVENT type.
Patches 9-12 clean up the way PSCI is tested in selftests to more easily
add new test cases.
Finally, the last patch actually tests that PSCI SYSTEM_SUSPEND calls
within the guest result in userspace exits.
Applies cleanly to kvmarm/fixes, at the following commit:
21db83846683 ("selftests: KVM: Free the GIC FD when cleaning up in arch_timer")
This is because there's some patches on the fixes branch that would
cause conflicts with this series otherwise.
Tested with the included selftest and a hacked up kvmtool [1] with support
for the new UAPI.
[1]: https://lore.kernel.org/all/20220311175717.616958-1-oupton@xxxxxxxxxx/
v4: http://lore.kernel.org/r/20220311174001.605719-1-oupton@xxxxxxxxxx
v4 -> v5:
- Rebase to kvmarm/fixes (5.18-rc1 + a bit more)
- Rework system event helper around RISC-V SBI changes (Anup)
- Don't presume a vCPU has been woken up when it returns from
kvm_vcpu_wfi(), as there are other situations where the vCPU thread
unblocks, such as signals. (Reiji)
- Tighten up comments/docs (Reiji)
Oliver Upton (13):
KVM: arm64: Don't depend on fallthrough to hide SYSTEM_RESET2
KVM: arm64: Dedupe vCPU power off helpers
KVM: arm64: Track vCPU power state using MP state values
KVM: arm64: Rename the KVM_REQ_SLEEP handler
KVM: Create helper for setting a system event exit
KVM: arm64: Return a value from check_vcpu_requests()
KVM: arm64: Add support for userspace to suspend a vCPU
KVM: arm64: Implement PSCI SYSTEM_SUSPEND
selftests: KVM: Rename psci_cpu_on_test to psci_test
selftests: KVM: Create helper for making SMCCC calls
selftests: KVM: Use KVM_SET_MP_STATE to power off vCPU in psci_test
selftests: KVM: Refactor psci_test to make it amenable to new tests
selftests: KVM: Test SYSTEM_SUSPEND PSCI call
Documentation/virt/kvm/api.rst | 76 ++++++-
arch/arm64/include/asm/kvm_host.h | 11 +-
arch/arm64/kvm/arm.c | 107 +++++++--
arch/arm64/kvm/psci.c | 66 +++---
arch/riscv/kvm/vcpu_sbi.c | 5 +-
arch/x86/kvm/x86.c | 6 +-
include/linux/kvm_host.h | 2 +
include/uapi/linux/kvm.h | 4 +
tools/testing/selftests/kvm/.gitignore | 2 +-
tools/testing/selftests/kvm/Makefile | 2 +-
.../selftests/kvm/aarch64/psci_cpu_on_test.c | 121 ----------
.../testing/selftests/kvm/aarch64/psci_test.c | 213 ++++++++++++++++++
.../selftests/kvm/include/aarch64/processor.h | 22 ++
.../selftests/kvm/lib/aarch64/processor.c | 25 ++
tools/testing/selftests/kvm/steal_time.c | 13 +-
virt/kvm/kvm_main.c | 8 +
16 files changed, 493 insertions(+), 190 deletions(-)
delete mode 100644 tools/testing/selftests/kvm/aarch64/psci_cpu_on_test.c
create mode 100644 tools/testing/selftests/kvm/aarch64/psci_test.c
--
2.35.1.1178.g4f1659d476-goog
