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From: Steffen Eiden <seiden@linux•ibm.com>
To: kvm@vger•kernel.org, kvmarm@lists•linux.dev,
	linux-arm-kernel@lists•infradead.org,
	linux-kernel@vger•kernel.org, linux-s390@vger•kernel.org
Cc: Alexander Gordeev <agordeev@linux•ibm.com>,
	Andreas Grapentin <gra@linux•ibm.com>,
	Arnd Bergmann <arnd@arndb•de>,
	Catalin Marinas <catalin.marinas@arm•com>,
	Christian Borntraeger <borntraeger@linux•ibm.com>,
	Claudio Imbrenda <imbrenda@linux•ibm.com>,
	David Hildenbrand <david@kernel•org>,
	Friedrich Welter <fritz@linux•ibm.com>,
	Gautam Gala <ggala@linux•ibm.com>,
	Hariharan Mari <hari55@linux•ibm.com>,
	Heiko Carstens <hca@linux•ibm.com>,
	Hendrik Brueckner <brueckner@linux•ibm.com>,
	Ilya Leoshkevich <iii@linux•ibm.com>,
	Janosch Frank <frankja@linux•ibm.com>,
	Joey Gouly <joey.gouly@arm•com>, Marc Zyngier <maz@kernel•org>,
	Nico Boehr <nrb@linux•ibm.com>,
	Nina Schoetterl-Glausch <oss@nina•schoetterlglausch.eu>,
	Oliver Upton <oupton@kernel•org>,
	Paolo Bonzini <pbonzini@redhat•com>,
	Suzuki K Poulose <suzuki.poulose@arm•com>,
	Sven Schnelle <svens@linux•ibm.com>,
	Ulrich Weigand <Ulrich.Weigand@de•ibm.com>,
	Vasily Gorbik <gor@linux•ibm.com>, Will Deacon <will@kernel•org>,
	Zenghui Yu <yuzenghui@huawei•com>
Subject: [PATCH v3 13/27] KVM: arm64: Extract & share ipa size shift calculation
Date: Fri, 29 May 2026 17:50:27 +0200	[thread overview]
Message-ID: <20260529155050.2902245-14-seiden@linux.ibm.com> (raw)
In-Reply-To: <20260529155050.2902245-1-seiden@linux.ibm.com>

Extract the ipa shift calculation from kvm_init_ipa_range into its own
function kvm_vm_type_ipa_size_shift to be shared across architectures.

User space passes a type parameter to the VM creation ioctl, indicating
the physical size of the VM. Therefore extract the ipa shift calculation
from kvm_init_ipa_range into its own function kvm_vm_type_ipa_size_shift,
so all implementers of arm64 KVM can make use of it for VM creation.

Co-developed-by: Nina Schoetterl-Glausch <nsg@linux•ibm.com>
Signed-off-by: Nina Schoetterl-Glausch <nsg@linux•ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux•ibm.com>
---
 arch/arm64/kvm/mmu.c         | 19 ++++++-------------
 include/kvm/arm64/kvm_host.h |  1 +
 virt/kvm/arm64/arm.c         | 21 +++++++++++++++++++++
 3 files changed, 28 insertions(+), 13 deletions(-)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index f683eb18c4ec..e202063fcdda 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -877,24 +877,17 @@ static struct kvm_pgtable_mm_ops kvm_s2_mm_ops = {
 
 static int kvm_init_ipa_range(struct kvm_s2_mmu *mmu, unsigned long type)
 {
-	u32 kvm_ipa_limit = get_kvm_ipa_limit();
 	u64 mmfr0, mmfr1;
 	u32 phys_shift;
+	int r;
 
-	phys_shift = KVM_VM_TYPE_ARM_IPA_SIZE(type);
 	if (is_protected_kvm_enabled()) {
-		phys_shift = kvm_ipa_limit;
-	} else if (phys_shift) {
-		if (phys_shift > kvm_ipa_limit ||
-		    phys_shift < ARM64_MIN_PARANGE_BITS)
-			return -EINVAL;
+		phys_shift = get_kvm_ipa_limit();
 	} else {
-		phys_shift = KVM_PHYS_SHIFT;
-		if (phys_shift > kvm_ipa_limit) {
-			pr_warn_once("%s using unsupported default IPA limit, upgrade your VMM\n",
-				     current->comm);
-			return -EINVAL;
-		}
+		r = kvm_vm_type_ipa_size_shift(type);
+		if (r < 0)
+			return r;
+		phys_shift = r;
 	}
 
 	mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
diff --git a/include/kvm/arm64/kvm_host.h b/include/kvm/arm64/kvm_host.h
index d36ebea4d60f..8bf399508757 100644
--- a/include/kvm/arm64/kvm_host.h
+++ b/include/kvm/arm64/kvm_host.h
@@ -33,6 +33,7 @@ int kvm_vcpu_init_check_features(struct kvm_vcpu *vcpu,
 				 const struct kvm_vcpu_init *init);
 bool kvm_vcpu_init_changed(struct kvm_vcpu *vcpu,
 			   const struct kvm_vcpu_init *init);
+int kvm_vm_type_ipa_size_shift(unsigned long type);
 
 /* MMIO helpers */
 void kvm_mmio_write_buf(void *buf, unsigned int len, unsigned long data);
diff --git a/virt/kvm/arm64/arm.c b/virt/kvm/arm64/arm.c
index b47adef65e5f..0bbfbe63e558 100644
--- a/virt/kvm/arm64/arm.c
+++ b/virt/kvm/arm64/arm.c
@@ -52,3 +52,24 @@ bool kvm_vcpu_init_changed(struct kvm_vcpu *vcpu,
 	return !bitmap_equal(vcpu->kvm->arch.vcpu_features, &features,
 			     KVM_VCPU_MAX_FEATURES);
 }
+
+int kvm_vm_type_ipa_size_shift(unsigned long type)
+{
+	int phys_shift;
+
+	phys_shift = KVM_VM_TYPE_ARM_IPA_SIZE(type);
+	if (phys_shift) {
+		if (phys_shift > get_kvm_ipa_limit() ||
+		    phys_shift < ARM64_MIN_PARANGE_BITS)
+			return -EINVAL;
+	} else {
+		phys_shift = KVM_PHYS_SHIFT;
+		if (phys_shift > get_kvm_ipa_limit()) {
+			pr_warn_once("%s using unsupported default IPA limit, upgrade your VMM\n",
+				     current->comm);
+			return -EINVAL;
+		}
+	}
+
+	return phys_shift;
+}
-- 
2.53.0



  parent reply	other threads:[~2026-05-29 15:56 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-29 15:50 [PATCH v3 00/27] KVM: s390: Introduce arm64 KVM Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 01/27] VFIO: take reference to the KVM module Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 02/27] KVM, vfio: remove symbol_get(kvm_get_kvm_safe) from vfio Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 03/27] KVM, vfio: remove symbol_get(kvm_put_kvm) " Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 04/27] uapi: KVM: Provide arm64 UAPI for other host architectures Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 05/27] arm64: Extract sysreg definitions Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 06/27] arm64: Provide arm64 API for non-native architectures Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 07/27] KVM: arm64: Provide arm64 KVM " Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 08/27] arm64: Extract pstate definitions from ptrace Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 09/27] KVM: arm64: Share kvm_emulate definitions Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 10/27] KVM: arm64: Make some arm64 KVM code shareable Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 11/27] KVM: arm64: Access elements of vcpu_gp_regs individually Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 12/27] KVM: arm64: Share reset general register code Steffen Eiden
2026-05-29 15:50 ` Steffen Eiden [this message]
2026-05-29 15:50 ` [PATCH v3 14/27] KVM: s390: Move s390 kvm code into a subdirectory Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 15/27] KVM: S390: Refactor gmap Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 16/27] KVM: Make device name configurable Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 17/27] KVM: Remove KVM_MMIO as config option Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 18/27] KVM: s390: Prepare kvm-s390 for a second kvm module Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 19/27] s390: Introduce Start Arm Execution instruction Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 20/27] KVM: s390: arm64: Introduce host definitions Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 21/27] s390/hwcaps: Report SAE support as hwcap Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 22/27] KVM: s390: Add basic arm64 kvm module Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 23/27] KVM: s390: arm64: Implement required functions Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 24/27] KVM: s390: arm64: Implement vm/vcpu create destroy Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 25/27] KVM: s390: arm64: Implement vCPU IOCTLs Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 26/27] KVM: s390: arm64: Implement basic page fault handler Steffen Eiden
2026-05-29 15:50 ` [PATCH v3 27/27] KVM: s390: arm64: Enable KVM_ARM64 config and Kbuild Steffen Eiden

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