[RFC PATCH 07/28] arm64: kvm: Allow passing machine type in KVM creation

Steven Price
2023-01-27T11:32:41Z

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.

Signed-off-by: Steven Price <steven.price@arm.com>
---
arch/arm64/kvm/arm.c | 13 +++++++++++++
arch/arm64/kvm/mmu.c | 3 ---
arch/arm64/kvm/reset.c | 3 ---
include/uapi/linux/kvm.h | 19 +++++++++++++++----
4 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 50f54a63732a..badd775547b8 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -147,6 +147,19 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
{
int ret;

+ 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;
+ break;
+ default:
+ return -EINVAL;
+ }
+
ret = kvm_share_hyp(kvm, kvm + 1);
if (ret)
return ret;
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index d0f707767d05..22c00274884a 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -709,9 +709,6 @@ int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu, unsigned long t
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/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index c165df174737..9e71d69e051f 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -405,9 +405,6 @@ int kvm_arm_setup_stage2(struct kvm *kvm, unsigned long type)
if (kvm_is_realm(kvm))
ipa_limit = kvm_realm_ipa_limit();

- if (type & ~KVM_VM_TYPE_ARM_IPA_SIZE_MASK)
- return -EINVAL;
-
phys_shift = KVM_VM_TYPE_ARM_IPA_SIZE(type);
if (phys_shift) {
if (phys_shift > ipa_limit ||
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index fec1909e8b73..bcfc4d58dc19 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -898,14 +898,25 @@ struct kvm_ppc_resize_hpt {
#define KVM_S390_SIE_PAGE_OFFSET 1

/*
- * On arm64, machine type can be used to request the physical
- * address size for the VM. Bits[7-0] are reserved for the guest
- * PA size shift (i.e, log2(PA_Size)). For backward compatibility,
- * value 0 implies the default IPA size, 40bits.
+ * On arm64, machine type can be used to request both the machine type and
+ * the physical address size for the VM.
+ *
+ * Bits[11-8] are reserved for the ARM specific machine type.
+ *
+ * Bits[7-0] are reserved for the guest PA size shift (i.e, log2(PA_Size)).
+ * For backward compatibility, value 0 implies the default IPA size, 40bits.
*/
+#define KVM_VM_TYPE_ARM_SHIFT 8
+#define KVM_VM_TYPE_ARM_MASK (0xfULL << KVM_VM_TYPE_ARM_SHIFT)
+#define KVM_VM_TYPE_ARM(_type) \
+ (((_type) << KVM_VM_TYPE_ARM_SHIFT) & KVM_VM_TYPE_ARM_MASK)
+#define KVM_VM_TYPE_ARM_NORMAL KVM_VM_TYPE_ARM(0)
+#define KVM_VM_TYPE_ARM_REALM KVM_VM_TYPE_ARM(1)
+
#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)
+
/*
* ioctls for /dev/kvm fds:
*/
--
2.34.1