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| author | Fuad Tabba <tabba@google.com> | 2024-04-23 17:05:37 +0200 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2024-05-01 17:48:14 +0200 |
| commit | 92536992cfd461207c78e46154d16050b236a6fc (patch) | |
| tree | fa1f06f460882b0b00e95639c7fd51fe2578e25a /arch/arm64/kvm/arm.c | |
| parent | KVM: arm64: Refactor setting the return value in kvm_vm_ioctl_enable_cap() (diff) | |
| download | linux-92536992cfd461207c78e46154d16050b236a6fc.tar.xz linux-92536992cfd461207c78e46154d16050b236a6fc.zip | |
KVM: arm64: Restrict supported capabilities for protected VMs
For practical reasons as well as security related ones, not all
capabilities are supported for protected VMs in pKVM.
Add a function that restricts the capabilities for protected VMs.
This behaves as an allow-list to ensure that future capabilities
are checked for compatibility and security before being allowed
for protected VMs.
Signed-off-by: Fuad Tabba <tabba@google.com>
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240423150538.2103045-30-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Diffstat (limited to '')
| -rw-r--r-- | arch/arm64/kvm/arm.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 1075b3cf9a3c..59b17948e7ed 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -69,6 +69,31 @@ int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu) return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE; } +/* + * This functions as an allow-list of protected VM capabilities. + * Features not explicitly allowed by this function are denied. + */ +static bool pkvm_ext_allowed(struct kvm *kvm, long ext) +{ + switch (ext) { + case KVM_CAP_IRQCHIP: + case KVM_CAP_ARM_PSCI: + case KVM_CAP_ARM_PSCI_0_2: + case KVM_CAP_NR_VCPUS: + case KVM_CAP_MAX_VCPUS: + case KVM_CAP_MAX_VCPU_ID: + case KVM_CAP_MSI_DEVID: + case KVM_CAP_ARM_VM_IPA_SIZE: + case KVM_CAP_ARM_PMU_V3: + case KVM_CAP_ARM_SVE: + case KVM_CAP_ARM_PTRAUTH_ADDRESS: + case KVM_CAP_ARM_PTRAUTH_GENERIC: + return true; + default: + return false; + } +} + int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap) { @@ -77,6 +102,9 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, if (cap->flags) return -EINVAL; + if (kvm_vm_is_protected(kvm) && !pkvm_ext_allowed(kvm, cap->cap)) + return -EINVAL; + switch (cap->cap) { case KVM_CAP_ARM_NISV_TO_USER: r = 0; @@ -215,6 +243,10 @@ void kvm_arch_destroy_vm(struct kvm *kvm) int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) { int r; + + if (kvm && kvm_vm_is_protected(kvm) && !pkvm_ext_allowed(kvm, ext)) + return 0; + switch (ext) { case KVM_CAP_IRQCHIP: r = vgic_present; |