[PATCH v6 10/43] arm64: kvm: Allow passing machine type in KVM creation
Gavin Shan
gshan at redhat.com
Tue Jan 28 20:07:51 PST 2025
On 12/13/24 1:55 AM, Steven Price wrote:
> Previously machine type was used purely for specifying the physical
> address size of the guest. Reserve the higher bits to specify an ARM
> specific machine type and declare a new type 'KVM_VM_TYPE_ARM_REALM'
> used to create a realm guest.
>
> Reviewed-by: Suzuki K Poulose <suzuki.poulose at arm.com>
> Signed-off-by: Steven Price <steven.price at arm.com>
> ---
> arch/arm64/kvm/arm.c | 17 +++++++++++++++++
> arch/arm64/kvm/mmu.c | 3 ---
> include/uapi/linux/kvm.h | 19 +++++++++++++++----
> 3 files changed, 32 insertions(+), 7 deletions(-)
>
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index c505ec61180a..73016e1e0067 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -207,6 +207,23 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
> mutex_unlock(&kvm->lock);
> #endif
>
> + if (type & ~(KVM_VM_TYPE_ARM_MASK | KVM_VM_TYPE_ARM_IPA_SIZE_MASK))
> + return -EINVAL;
> +
> + switch (type & KVM_VM_TYPE_ARM_MASK) {
> + case KVM_VM_TYPE_ARM_NORMAL:
> + break;
> + case KVM_VM_TYPE_ARM_REALM:
> + kvm->arch.is_realm = true;
> + if (!kvm_is_realm(kvm)) {
> + /* Realm support unavailable */
> + return -EINVAL;
> + }
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> kvm_init_nested(kvm);
>
> ret = kvm_share_hyp(kvm, kvm + 1);
Corresponding to comments for PATCH[6], the block of the code can be modified
to avoid using kvm_is_realm() here. In this way, kvm_is_realm() can be simplifed
as I commented for PATCH[6].
case KVM_VM_TYPE_ARM_REALM:
if (static_branch_unlikely(&kvm_rme_is_available))
return -EPERM; /* -EPERM may be more suitable than -EINVAL */
kvm->arch.is_realm = true;
break;
Thanks,
Gavin
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