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From: Steven Price <steven.price@arm.com>
To: kvm@vger.kernel.org,
	kvmarm@lists.linux.dev
Cc: Steven Price <steven.price@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Marc Zyngier <maz@kernel.org>,
	Will Deacon <will@kernel.org>,
	James Morse <james.morse@arm.com>,
	Oliver Upton <oliver.upton@linux.dev>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Zenghui Yu <yuzenghui@huawei.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Joey Gouly <joey.gouly@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Christoffer Dall <christoffer.dall@arm.com>,
	Fuad Tabba <tabba@google.com>,
	linux-coco@lists.linux.dev,
	Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>
Subject: [PATCH v2 11/43] arm64: kvm: Allow passing machine type in KVM creation
Date: Fri, 12 Apr 2024 09:42:37 +0100
Message-Id: <20240412084309.1733783-12-steven.price@arm.com>
In-Reply-To: <20240412084309.1733783-1-steven.price@arm.com>
References: <20240412084056.1733704-1-steven.price@arm.com>
 <20240412084309.1733783-1-steven.price@arm.com>
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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     | 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 22da6493912a..c5a6139d5454 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -173,6 +173,23 @@ 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;
+	}
+
 	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 aae365647b62..af4564f3add5 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -877,9 +877,6 @@ int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu, unsigned long t
 	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 (is_protected_kvm_enabled()) {
 		phys_shift = kvm_ipa_limit;
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index a1147036d1bd..5153c837c8c7 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -635,14 +635,25 @@ struct kvm_enable_cap {
 #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