linux-kernel - [PATCH v7 13/45] KVM: arm64: vgic: Provide helper for number of list registers

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Message-ID: <20250213161426.102987-14-steven.price@arm.com>
Date: Thu, 13 Feb 2025 16:13:53 +0000
From: Steven Price <steven.price@....com>
To: kvm@...r.kernel.org,
	kvmarm@...ts.linux.dev
Cc: Steven Price <steven.price@....com>,
	Catalin Marinas <catalin.marinas@....com>,
	Marc Zyngier <maz@...nel.org>,
	Will Deacon <will@...nel.org>,
	James Morse <james.morse@....com>,
	Oliver Upton <oliver.upton@...ux.dev>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	Zenghui Yu <yuzenghui@...wei.com>,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	Joey Gouly <joey.gouly@....com>,
	Alexandru Elisei <alexandru.elisei@....com>,
	Christoffer Dall <christoffer.dall@....com>,
	Fuad Tabba <tabba@...gle.com>,
	linux-coco@...ts.linux.dev,
	Ganapatrao Kulkarni <gankulkarni@...amperecomputing.com>,
	Gavin Shan <gshan@...hat.com>,
	Shanker Donthineni <sdonthineni@...dia.com>,
	Alper Gun <alpergun@...gle.com>,
	"Aneesh Kumar K . V" <aneesh.kumar@...nel.org>
Subject: [PATCH v7 13/45] KVM: arm64: vgic: Provide helper for number of list registers

Currently the number of list registers available is stored in a global
(kvm_vgic_global_state.nr_lr). With Arm CCA the RMM is permitted to
reserve list registers for its own use and so the number of available
list registers can be fewer for a realm VM. Provide a wrapper function
to fetch the global in preparation for restricting nr_lr when dealing
with a realm VM.

Signed-off-by: Steven Price <steven.price@....com>
---
New patch for v6
---
 arch/arm64/kvm/vgic/vgic.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c
index cc8c6b9b5dd8..1077fab2df4b 100644
--- a/arch/arm64/kvm/vgic/vgic.c
+++ b/arch/arm64/kvm/vgic/vgic.c
@@ -21,6 +21,11 @@ struct vgic_global kvm_vgic_global_state __ro_after_init = {
 	.gicv3_cpuif = STATIC_KEY_FALSE_INIT,
 };
 
+static inline int kvm_vcpu_vgic_nr_lr(struct kvm_vcpu *vcpu)
+{
+	return kvm_vgic_global_state.nr_lr;
+}
+
 /*
  * Locking order is always:
  * kvm->lock (mutex)
@@ -802,7 +807,7 @@ static void vgic_flush_lr_state(struct kvm_vcpu *vcpu)
 	lockdep_assert_held(&vgic_cpu->ap_list_lock);
 
 	count = compute_ap_list_depth(vcpu, &multi_sgi);
-	if (count > kvm_vgic_global_state.nr_lr || multi_sgi)
+	if (count > kvm_vcpu_vgic_nr_lr(vcpu) || multi_sgi)
 		vgic_sort_ap_list(vcpu);
 
 	count = 0;
@@ -831,7 +836,7 @@ static void vgic_flush_lr_state(struct kvm_vcpu *vcpu)
 
 		raw_spin_unlock(&irq->irq_lock);
 
-		if (count == kvm_vgic_global_state.nr_lr) {
+		if (count == kvm_vcpu_vgic_nr_lr(vcpu)) {
 			if (!list_is_last(&irq->ap_list,
 					  &vgic_cpu->ap_list_head))
 				vgic_set_underflow(vcpu);
@@ -840,7 +845,7 @@ static void vgic_flush_lr_state(struct kvm_vcpu *vcpu)
 	}
 
 	/* Nuke remaining LRs */
-	for (i = count ; i < kvm_vgic_global_state.nr_lr; i++)
+	for (i = count ; i < kvm_vcpu_vgic_nr_lr(vcpu); i++)
 		vgic_clear_lr(vcpu, i);
 
 	if (!static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
-- 
2.43.0