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KVM: arm64: Allow userspace to create protected VMs when pKVM is enabled

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Introduce a new VM type for KVM/arm64 to allow userspace to request the
creation of a "protected VM" when the host has booted with pKVM enabled.

For now, this feature results in a taint on first use as many aspects of
a protected VM are not yet protected!

Tested-by: Fuad Tabba <tabba@google.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Link: https://patch.msgid.link/20260330144841.26181-32-will@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Will Deacon 2026-03-30 15:48:32 +01:00 committed by Marc Zyngier
parent 246c976c37
commit 8800dbf661
5 changed files with 20 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/arm64/include/asm/kvm_pkvm.h
View File

@ -17,7 +17,7 @@
#define HYP_MEMBLOCK_REGIONS 128 #define HYP_MEMBLOCK_REGIONS 128
int pkvm_init_host_vm(struct kvm *kvm); int pkvm_init_host_vm(struct kvm *kvm, unsigned long type);
int pkvm_create_hyp_vm(struct kvm *kvm); int pkvm_create_hyp_vm(struct kvm *kvm);
bool pkvm_hyp_vm_is_created(struct kvm *kvm); bool pkvm_hyp_vm_is_created(struct kvm *kvm);
void pkvm_destroy_hyp_vm(struct kvm *kvm); void pkvm_destroy_hyp_vm(struct kvm *kvm);

8
arch/arm64/kvm/arm.c
View File

@ -203,6 +203,9 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
{ {
int ret; int ret;
if (type & ~KVM_VM_TYPE_ARM_MASK)
return -EINVAL;
mutex_init(&kvm->arch.config_lock); mutex_init(&kvm->arch.config_lock);
#ifdef CONFIG_LOCKDEP #ifdef CONFIG_LOCKDEP
@ -234,9 +237,12 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
* If any failures occur after this is successful, make sure to * If any failures occur after this is successful, make sure to
* call __pkvm_unreserve_vm to unreserve the VM in hyp. * call __pkvm_unreserve_vm to unreserve the VM in hyp.
*/ */
ret = pkvm_init_host_vm(kvm); ret = pkvm_init_host_vm(kvm, type);
if (ret) if (ret)
goto err_uninit_mmu; goto err_uninit_mmu;
} else if (type & KVM_VM_TYPE_ARM_PROTECTED) {
ret = -EINVAL;
goto err_uninit_mmu;
} }
kvm_vgic_early_init(kvm); kvm_vgic_early_init(kvm);

3
arch/arm64/kvm/mmu.c
View File

@ -881,9 +881,6 @@ static int kvm_init_ipa_range(struct kvm_s2_mmu *mmu, unsigned long type)
u64 mmfr0, mmfr1; u64 mmfr0, mmfr1;
u32 phys_shift; u32 phys_shift;
if (type & ~KVM_VM_TYPE_ARM_IPA_SIZE_MASK)
return -EINVAL;
phys_shift = KVM_VM_TYPE_ARM_IPA_SIZE(type); phys_shift = KVM_VM_TYPE_ARM_IPA_SIZE(type);
if (is_protected_kvm_enabled()) { if (is_protected_kvm_enabled()) {
phys_shift = kvm_ipa_limit; phys_shift = kvm_ipa_limit;

8
arch/arm64/kvm/pkvm.c
View File

@ -225,9 +225,10 @@ void pkvm_destroy_hyp_vm(struct kvm *kvm)
mutex_unlock(&kvm->arch.config_lock); mutex_unlock(&kvm->arch.config_lock);
} }
int pkvm_init_host_vm(struct kvm *kvm) int pkvm_init_host_vm(struct kvm *kvm, unsigned long type)
{ {
int ret; int ret;
bool protected = type & KVM_VM_TYPE_ARM_PROTECTED;
if (pkvm_hyp_vm_is_created(kvm)) if (pkvm_hyp_vm_is_created(kvm))
return -EINVAL; return -EINVAL;
@ -242,6 +243,11 @@ int pkvm_init_host_vm(struct kvm *kvm)
return ret; return ret;
kvm->arch.pkvm.handle = ret; kvm->arch.pkvm.handle = ret;
kvm->arch.pkvm.is_protected = protected;
if (protected) {
pr_warn_once("kvm: protected VMs are experimental and for development only, tainting kernel\n");
add_taint(TAINT_USER, LOCKDEP_STILL_OK);
}
return 0; return 0;
} }

5
include/uapi/linux/kvm.h
View File

@ -703,6 +703,11 @@ struct kvm_enable_cap {
#define KVM_VM_TYPE_ARM_IPA_SIZE_MASK 0xffULL #define KVM_VM_TYPE_ARM_IPA_SIZE_MASK 0xffULL
#define KVM_VM_TYPE_ARM_IPA_SIZE(x) \ #define KVM_VM_TYPE_ARM_IPA_SIZE(x) \
((x) & KVM_VM_TYPE_ARM_IPA_SIZE_MASK) ((x) & KVM_VM_TYPE_ARM_IPA_SIZE_MASK)
#define KVM_VM_TYPE_ARM_PROTECTED (1UL << 31)
#define KVM_VM_TYPE_ARM_MASK (KVM_VM_TYPE_ARM_IPA_SIZE_MASK | \
KVM_VM_TYPE_ARM_PROTECTED)
/* /*
* ioctls for /dev/kvm fds: * ioctls for /dev/kvm fds:
*/ */