[PATCH v6 06/43] arm64: RME: Check for RME support at KVM init
Gavin Shan
gshan at redhat.com
Tue Jan 28 19:57:23 PST 2025
On 12/13/24 1:55 AM, Steven Price wrote:
> Query the RMI version number and check if it is a compatible version. A
> static key is also provided to signal that a supported RMM is available.
>
> Functions are provided to query if a VM or VCPU is a realm (or rec)
> which currently will always return false.
>
> Signed-off-by: Steven Price <steven.price at arm.com>
> ---
> Changes since v5:
> * Reword "unsupported" message from "host supports" to "we want" to
> clarify that 'we' are the 'host'.
> Changes since v2:
> * Drop return value from kvm_init_rme(), it was always 0.
> * Rely on the RMM return value to identify whether the RSI ABI is
> compatible.
> ---
> arch/arm64/include/asm/kvm_emulate.h | 18 +++++++++
> arch/arm64/include/asm/kvm_host.h | 4 ++
> arch/arm64/include/asm/kvm_rme.h | 56 ++++++++++++++++++++++++++++
> arch/arm64/include/asm/virt.h | 1 +
> arch/arm64/kvm/Makefile | 3 +-
> arch/arm64/kvm/arm.c | 6 +++
> arch/arm64/kvm/rme.c | 50 +++++++++++++++++++++++++
> 7 files changed, 137 insertions(+), 1 deletion(-)
> create mode 100644 arch/arm64/include/asm/kvm_rme.h
> create mode 100644 arch/arm64/kvm/rme.c
>
[...]
> +
> +static inline bool kvm_is_realm(struct kvm *kvm)
> +{
> + if (static_branch_unlikely(&kvm_rme_is_available) && kvm)
> + return kvm->arch.is_realm;
> + return false;
> +}
> +
kvm->arch.is_realm won't be true when kvm_rme_is_available is false. It's set
in kvm_arch_init_vm() of PATCH[10]. So it's safe to be simplified as below if
the changes to kvm_arch_init_vm() is slightly modified, more details can be
found from the comments to PATCH[10]
With the changes, we don't have to check kvm_rme_is_available every time.
static inline bool kvm_is_realm(struct kvm *kvm)
{
return (kvm && kvm->arch.is_realm);
}
Thanks,
Gavin
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