Re: [PATCH] target/arm: Report KVM's actual PSCI version to guest in dtb

[Andrew Jones]

On Thu, Feb 24, 2022 at 01:46:54PM +0000, Peter Maydell wrote:
> When we're using KVM, the PSCI implementation is provided by the
> kernel, but QEMU has to tell the guest about it via the device tree.
> Currently we look at the KVM_CAP_ARM_PSCI_0_2 capability to determine
> if the kernel is providing at least PSCI 0.2, but if the kernel
> provides a newer version than that we will still only tell the guest
> it has PSCI 0.2.  (This is fairly harmless; it just means the guest
> won't use newer parts of the PSCI API.)
> 
> The kernel exposes the specific PSCI version it is implementing via
> the ONE_REG API; use this to report in the dtb that the PSCI
> implementation is 1.0-compatible if appropriate.  (The device tree
> binding currently only distinguishes "pre-0.2", "0.2-compatible" and
> "1.0-compatible".)
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
> Based-on: 20220213035753.34577-1-akihiko.odaki@gmail.com
> ("[PATCH v2] target/arm: Support PSCI 1.1 and SMCCC 1.0")
> though note that to compile on arm hosts you'll need the
> bugfix to that patch from which I describe in a reply to it.
> 
>  target/arm/kvm-consts.h |  1 +
>  hw/arm/boot.c           |  5 ++---
>  target/arm/kvm64.c      | 12 ++++++++++++
>  3 files changed, 15 insertions(+), 3 deletions(-)
>

Reviewed-by: Andrew Jones <drjones@redhat.com>