Introduce a new virtual machine type,
KVM_VM_TYPE_ARM_SW_PROTECTED, to serve as a development and
testing vehicle for Confidential (CoCo) VMs, similar to the x86
KVM_X86_SW_PROTECTED_VM type.
Initially, this is used to test guest_memfd without needing any
underlying protection.
Similar to the x86 type, this is currently only for development
and testing. Do not use KVM_VM_TYPE_ARM_SW_PROTECTED for "real"
VMs, and especially not in production. The behavior and effective
ABI for software-protected VMs is unstable.
Signed-off-by: Fuad Tabba <tabba@xxxxxxxxxx>
---
Documentation/virt/kvm/api.rst | 5 +++++
arch/arm64/include/asm/kvm_host.h | 10 ++++++++++
arch/arm64/kvm/arm.c | 5 +++++
arch/arm64/kvm/mmu.c | 3 ---
include/uapi/linux/kvm.h | 6 ++++++
5 files changed, 26 insertions(+), 3 deletions(-)
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 2b52eb77e29c..0fccee4feee7 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -214,6 +214,11 @@ exposed by the guest CPUs in ID_AA64MMFR0_EL1[PARange]. It only affects
size of the address translated by the stage2 level (guest physical to
host physical address translations).
+KVM_VM_TYPE_ARM_SW_PROTECTED is currently only for development and testing of
+confidential VMs without having underlying support. Do not use
+KVM_VM_TYPE_ARM_SW_PROTECTED for "real" VMs, and especially not in production.
+The behavior and effective ABI for software-protected VMs is unstable.
+
4.3 KVM_GET_MSR_INDEX_LIST, KVM_GET_MSR_FEATURE_INDEX_LIST
----------------------------------------------------------
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 7cfa024de4e3..a4276d56f54d 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -383,6 +383,8 @@ struct kvm_arch {
* the associated pKVM instance in the hypervisor.
*/
struct kvm_protected_vm pkvm;
+
+ unsigned long vm_type;
};
struct kvm_vcpu_fault_info {
@@ -1555,4 +1557,12 @@ void kvm_set_vm_id_reg(struct kvm *kvm, u32 reg, u64 val);
#define kvm_has_s1poe(k) \
(kvm_has_feat((k), ID_AA64MMFR3_EL1, S1POE, IMP))
+#define kvm_arch_has_private_mem(kvm) \
+ (IS_ENABLED(CONFIG_KVM_PRIVATE_MEM) && \
+ ((kvm)->arch.vm_type & KVM_VM_TYPE_ARM_SW_PROTECTED))
+
+#define kvm_arch_gmem_supports_shared_mem(kvm) \
+ (IS_ENABLED(CONFIG_KVM_GMEM_SHARED_MEM) && \
+ ((kvm)->arch.vm_type & KVM_VM_TYPE_ARM_SW_PROTECTED))
+
#endif /* __ARM64_KVM_HOST_H__ */
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 071a7d75be68..a2066db52ada 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -146,6 +146,9 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
{
int ret;
+ if (type & ~KVM_VM_TYPE_MASK)
+ return -EINVAL;
+
mutex_init(&kvm->arch.config_lock);
#ifdef CONFIG_LOCKDEP
@@ -187,6 +190,8 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
bitmap_zero(kvm->arch.vcpu_features, KVM_VCPU_MAX_FEATURES);
+ kvm->arch.vm_type = type;
+
return 0;
err_free_cpumask:
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 305060518766..b89649d31127 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -882,9 +882,6 @@ static int kvm_init_ipa_range(struct kvm_s2_mmu *mmu, unsigned long type)
u64 mmfr0, mmfr1;
u32 phys_shift;
- if (type & ~KVM_VM_TYPE_ARM_IPA_SIZE_MASK)
- return -EINVAL;
-
phys_shift = KVM_VM_TYPE_ARM_IPA_SIZE(type);
if (is_protected_kvm_enabled()) {
phys_shift = kvm_ipa_limit;
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 117937a895da..f155d3781e08 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -652,6 +652,12 @@ struct kvm_enable_cap {
#define KVM_VM_TYPE_ARM_IPA_SIZE_MASK 0xffULL
#define KVM_VM_TYPE_ARM_IPA_SIZE(x) \
((x) & KVM_VM_TYPE_ARM_IPA_SIZE_MASK)
+
+#define KVM_VM_TYPE_ARM_SW_PROTECTED (1UL << 9)
+
+#define KVM_VM_TYPE_MASK (KVM_VM_TYPE_ARM_IPA_SIZE_MASK | \
+ KVM_VM_TYPE_ARM_SW_PROTECTED)
+
/*
* ioctls for /dev/kvm fds:
*/
--
2.48.1.502.g6dc24dfdaf-goog
