Documentation/virt/kvm/api.rst | 11 +++ arch/arm64/include/uapi/asm/kvm.h | 6 ++ arch/arm64/kvm/hyp/nvhe/psci-relay.c | 2 + arch/arm64/kvm/hypercalls.c | 2 + arch/arm64/kvm/psci.c | 50 ++++++++++++- drivers/firmware/psci/psci.c | 42 +++++++++++ include/kvm/arm_psci.h | 4 +- include/uapi/linux/psci.h | 5 ++ kernel/power/hibernate.c | 5 +- tools/testing/selftests/kvm/aarch64/psci_test.c | 93 +++++++++++++++++++++++++ 10 files changed, 217 insertions(+), 3 deletions(-)
The PSCI v1.3 spec (https://developer.arm.com/documentation/den0022)
adds support for a SYSTEM_OFF2 function enabling a HIBERNATE_OFF state
which is analogous to ACPI S4. This will allow hosting environments to
determine that a guest is hibernated rather than just powered off, and
ensure that they preserve the virtual environment appropriately to
allow the guest to resume safely (or bump the hardware_signature in the
FACS to trigger a clean reboot instead).
This updates KVM to support advertising PSCI v1.3, and unconditionally
enables the SYSTEM_OFF2 support when PSCI v1.3 is enabled.
For the guest side, add a new SYS_OFF_MODE_POWER_OFF handler with higher
priority than the EFI one, but which *only* triggers when there's a
hibernation in progress. There are other ways to do this (see the commit
message for more details) but this seemed like the simplest.
Version 2 of the patch series splits out the psci.h definitions into a
separate commit (a dependency for both the guest and KVM side), and adds
definitions for the other new functions added in v1.3. It also moves the
pKVM psci-relay support to a separate commit; although in arch/arm64/kvm
that's actually about the *guest* side of SYSTEM_OFF2 (i.e. using it
from the host kernel, relayed through nVHE).
Version 3 dropped the KVM_CAP which allowed userspace to explicitly opt
in to the new feature like with SYSTEM_SUSPEND, and makes it depend only
on PSCI v1.3 being exposed to the guest.
Version 4 is no longer RFC, as the PSCI v1.3 spec is finally published.
Minor fixes from the last round of review, and an added KVM self test.
Version 5 drops some of the changes which didn't make it to the final
v1.3 spec, and cleans up a couple of places which still referred to it
as 'alpha' or 'beta'. It also temporarily drops the guest-side patch to
invoke SYSTEM_OFF2 for hibernation, pending confirmation that the final
PSCI v1.3 spec just has a typo where it changed to saying that 0x1
should be passed to mean HIBERNATE_OFF, even though it's advertised as
bit 0. That can be sent under separate cover, and perhaps should have
been anyway. The change in question doesn't matter for any of the KVM
patches, because we just treat SYSTEM_OFF2 like the existing
SYSTEM_RESET2, setting a flag to indicate that it was a SYSTEM_OFF2
call, but not actually caring about the argument; that's for userspace
to worry about.
Version 6 is updated to revision F.b of the specification, allowing both
0x0 and 0x1 to indicate HIBERNATE_OFF in the SYSTEM_OFF2 call, as well
as disallowing anything but zero in the second argument. The test is
expanded to cover those variants, and to require PSCI v1.3 instead of
skipping on older kernels. The final guest-side patch in the series is
reinstated, using zero as the argument for compatibility with existing
hypervisors in the field as permitted by revision F.b. allows for zero
as well as 0x1 for HIBERNATE_OFF to accommodate the change in the final
version of the spec, and expands the test to cover both forms as well as
checking that a non-zero second argument is correctly rejected.
David Woodhouse (6):
firmware/psci: Add definitions for PSCI v1.3 specification
KVM: arm64: Add PSCI v1.3 SYSTEM_OFF2 function for hibernation
KVM: arm64: Add support for PSCI v1.2 and v1.3
KVM: selftests: Add test for PSCI SYSTEM_OFF2
KVM: arm64: nvhe: Pass through PSCI v1.3 SYSTEM_OFF2 call
arm64: Use SYSTEM_OFF2 PSCI call to power off for hibernate
Documentation/virt/kvm/api.rst | 11 +++
arch/arm64/include/uapi/asm/kvm.h | 6 ++
arch/arm64/kvm/hyp/nvhe/psci-relay.c | 2 +
arch/arm64/kvm/hypercalls.c | 2 +
arch/arm64/kvm/psci.c | 50 ++++++++++++-
drivers/firmware/psci/psci.c | 42 +++++++++++
include/kvm/arm_psci.h | 4 +-
include/uapi/linux/psci.h | 5 ++
kernel/power/hibernate.c | 5 +-
tools/testing/selftests/kvm/aarch64/psci_test.c | 93 +++++++++++++++++++++++++
10 files changed, 217 insertions(+), 3 deletions(-)
On Sat, 19 Oct 2024 18:15:41 +0100, David Woodhouse wrote:
> The PSCI v1.3 spec (https://developer.arm.com/documentation/den0022)
> adds support for a SYSTEM_OFF2 function enabling a HIBERNATE_OFF state
> which is analogous to ACPI S4. This will allow hosting environments to
> determine that a guest is hibernated rather than just powered off, and
> ensure that they preserve the virtual environment appropriately to
> allow the guest to resume safely (or bump the hardware_signature in the
> FACS to trigger a clean reboot instead).
>
> [...]
Thanks Catalin for the ack, as promised:
Applied to kvmarm/next, thanks!
[6/6] arm64: Use SYSTEM_OFF2 PSCI call to power off for hibernate
https://git.kernel.org/kvmarm/kvmarm/c/3e251afaec9a
--
Best,
Oliver
On Thu, 2024-10-31 at 17:56 +0000, Oliver Upton wrote: > On Sat, 19 Oct 2024 18:15:41 +0100, David Woodhouse wrote: > > The PSCI v1.3 spec (https://developer.arm.com/documentation/den0022) > > adds support for a SYSTEM_OFF2 function enabling a HIBERNATE_OFF state > > which is analogous to ACPI S4. This will allow hosting environments to > > determine that a guest is hibernated rather than just powered off, and > > ensure that they preserve the virtual environment appropriately to > > allow the guest to resume safely (or bump the hardware_signature in the > > FACS to trigger a clean reboot instead). > > > > [...] > > Thanks Catalin for the ack, as promised: > > Applied to kvmarm/next, thanks! > > [6/6] arm64: Use SYSTEM_OFF2 PSCI call to power off for hibernate > https://git.kernel.org/kvmarm/kvmarm/c/3e251afaec9a Thank you.
On Sat, 19 Oct 2024 18:15:41 +0100, David Woodhouse wrote:
> The PSCI v1.3 spec (https://developer.arm.com/documentation/den0022)
> adds support for a SYSTEM_OFF2 function enabling a HIBERNATE_OFF state
> which is analogous to ACPI S4. This will allow hosting environments to
> determine that a guest is hibernated rather than just powered off, and
> ensure that they preserve the virtual environment appropriately to
> allow the guest to resume safely (or bump the hardware_signature in the
> FACS to trigger a clean reboot instead).
>
> [...]
I grabbed the KVM portions of this series, as they look ready to go. Happy
to take the last one through kvmarm tree w/ acks, and can toss it on top.
Applied to kvmarm/next, thanks!
[1/6] firmware/psci: Add definitions for PSCI v1.3 specification
https://git.kernel.org/kvmarm/kvmarm/c/2f2d46959808
[2/6] KVM: arm64: Add PSCI v1.3 SYSTEM_OFF2 function for hibernation
https://git.kernel.org/kvmarm/kvmarm/c/97413cea1c48
[3/6] KVM: arm64: Add support for PSCI v1.2 and v1.3
https://git.kernel.org/kvmarm/kvmarm/c/8be82d536a9f
[4/6] KVM: selftests: Add test for PSCI SYSTEM_OFF2
https://git.kernel.org/kvmarm/kvmarm/c/72be5aa6be4a
[5/6] KVM: arm64: nvhe: Pass through PSCI v1.3 SYSTEM_OFF2 call
https://git.kernel.org/kvmarm/kvmarm/c/94f985c39a1e
--
Best,
Oliver
On Fri, Oct 25, 2024 at 10:12:41PM +0000, Oliver Upton wrote: > On Sat, 19 Oct 2024 18:15:41 +0100, David Woodhouse wrote: > > The PSCI v1.3 spec (https://developer.arm.com/documentation/den0022) > > adds support for a SYSTEM_OFF2 function enabling a HIBERNATE_OFF state > > which is analogous to ACPI S4. This will allow hosting environments to > > determine that a guest is hibernated rather than just powered off, and > > ensure that they preserve the virtual environment appropriately to > > allow the guest to resume safely (or bump the hardware_signature in the > > FACS to trigger a clean reboot instead). > > > > [...] > > I grabbed the KVM portions of this series, as they look ready to go. Happy > to take the last one through kvmarm tree w/ acks, and can toss it on top. Happy for you to take the last patch as well through the KVM tree. Feel free to adjust the code comment as you see fit. -- Catalin
On Thu, 2024-10-31 at 12:15 +0000, Catalin Marinas wrote: > On Fri, Oct 25, 2024 at 10:12:41PM +0000, Oliver Upton wrote: > > On Sat, 19 Oct 2024 18:15:41 +0100, David Woodhouse wrote: > > > The PSCI v1.3 spec (https://developer.arm.com/documentation/den0022) > > > adds support for a SYSTEM_OFF2 function enabling a HIBERNATE_OFF state > > > which is analogous to ACPI S4. This will allow hosting environments to > > > determine that a guest is hibernated rather than just powered off, and > > > ensure that they preserve the virtual environment appropriately to > > > allow the guest to resume safely (or bump the hardware_signature in the > > > FACS to trigger a clean reboot instead). > > > > > > [...] > > > > I grabbed the KVM portions of this series, as they look ready to go. Happy > > to take the last one through kvmarm tree w/ acks, and can toss it on top. > > Happy for you to take the last patch as well through the KVM tree. Feel > free to adjust the code comment as you see fit. Thanks. that's probably the best option, as it depends on the definitions in psci.h.
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