[PATCH v6 28/43] arm64: rme: Allow checking SVE on VM instance
Gavin Shan
gshan at redhat.com
Sat Feb 1 22:00:25 PST 2025
On 12/13/24 1:55 AM, Steven Price wrote:
> From: Suzuki K Poulose <suzuki.poulose at arm.com>
>
> Given we have different types of VMs supported, check the
> support for SVE for the given instance of the VM to accurately
> report the status.
>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose at arm.com>
> Signed-off-by: Steven Price <steven.price at arm.com>
> ---
> arch/arm64/include/asm/kvm_rme.h | 2 ++
> arch/arm64/kvm/arm.c | 5 ++++-
> arch/arm64/kvm/rme.c | 5 +++++
> 3 files changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
> index 90a4537ad38d..0d89ab1645c1 100644
> --- a/arch/arm64/include/asm/kvm_rme.h
> +++ b/arch/arm64/include/asm/kvm_rme.h
> @@ -85,6 +85,8 @@ void kvm_init_rme(void);
> u32 kvm_realm_ipa_limit(void);
> u32 kvm_realm_vgic_nr_lr(void);
>
> +bool kvm_rme_supports_sve(void);
> +
> int kvm_realm_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap);
> int kvm_init_realm_vm(struct kvm *kvm);
> void kvm_destroy_realm(struct kvm *kvm);
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 134acb4ee26f..6f7f96ab781d 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -456,7 +456,10 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
> r = get_kvm_ipa_limit();
> break;
> case KVM_CAP_ARM_SVE:
> - r = system_supports_sve();
> + if (kvm_is_realm(kvm))
> + r = kvm_rme_supports_sve();
> + else
> + r = system_supports_sve();
> break;
kvm_vm_ioctl_check_extension() can be called by ioctl(KVM_CHECK_EXTENSION) on the
file descriptor of '/dev/kvm'. kvm is NULL and kvm_is_realm() returns false in
this case.
kvm_dev_ioctl
kvm_vm_ioctl_check_extension_generic // kvm is NULL
kvm_vm_ioctl_check_extension
> case KVM_CAP_ARM_PTRAUTH_ADDRESS:
> case KVM_CAP_ARM_PTRAUTH_GENERIC:
> diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
> index 5831d379760a..27a479feb907 100644
> --- a/arch/arm64/kvm/rme.c
> +++ b/arch/arm64/kvm/rme.c
> @@ -20,6 +20,11 @@ static bool rme_supports(unsigned long feature)
> return !!u64_get_bits(rmm_feat_reg0, feature);
> }
>
> +bool kvm_rme_supports_sve(void)
> +{
> + return rme_supports(RMI_FEATURE_REGISTER_0_SVE_EN);
> +}
> +
If rme_supports() becomes a public helper, it can be directly used. In turn,
kvm_rme_supports_sve() can be dropped. RMI_FEATURE_REGISTER_0_SVE_EN is obvious
to indicate the corresponding feature.
> static int rmi_check_version(void)
> {
> struct arm_smccc_res res;
Thanks,
Gavin
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