linux-kernel - [PATCH v4 09/10] KVM: arm64: Stage-2 huge mappings for np-guests

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Message-ID: <20250509131706.2336138-10-vdonnefort@google.com>
Date: Fri,  9 May 2025 14:17:05 +0100
From: Vincent Donnefort <vdonnefort@...gle.com>
To: maz@...nel.org, oliver.upton@...ux.dev, joey.gouly@....com, 
	suzuki.poulose@....com, yuzenghui@...wei.com, catalin.marinas@....com, 
	will@...nel.org
Cc: qperret@...gle.com, linux-arm-kernel@...ts.infradead.org, 
	kvmarm@...ts.linux.dev, linux-kernel@...r.kernel.org, kernel-team@...roid.com, 
	Vincent Donnefort <vdonnefort@...gle.com>
Subject: [PATCH v4 09/10] KVM: arm64: Stage-2 huge mappings for np-guests

Now np-guests hypercalls with range are supported, we can let the
hypervisor to install block mappings whenever the Stage-1 allows it,
that is when backed by either Hugetlbfs or THPs. The size of those block
mappings is limited to PMD_SIZE.

Signed-off-by: Vincent Donnefort <vdonnefort@...gle.com>

diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index 78fb9cea2034..97e0fea9db4e 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -167,7 +167,7 @@ int kvm_host_prepare_stage2(void *pgt_pool_base)
 static bool guest_stage2_force_pte_cb(u64 addr, u64 end,
 				      enum kvm_pgtable_prot prot)
 {
-	return true;
+	return false;
 }
 
 static void *guest_s2_zalloc_pages_exact(size_t size)
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 754f2fe0cc67..7c8be22e81f9 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1537,7 +1537,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	 * logging_active is guaranteed to never be true for VM_PFNMAP
 	 * memslots.
 	 */
-	if (logging_active || is_protected_kvm_enabled()) {
+	if (logging_active) {
 		force_pte = true;
 		vma_shift = PAGE_SHIFT;
 	} else {
@@ -1547,7 +1547,8 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	switch (vma_shift) {
 #ifndef __PAGETABLE_PMD_FOLDED
 	case PUD_SHIFT:
-		if (fault_supports_stage2_huge_mapping(memslot, hva, PUD_SIZE))
+		if (!is_protected_kvm_enabled() &&
+		    fault_supports_stage2_huge_mapping(memslot, hva, PUD_SIZE))
 			break;
 		fallthrough;
 #endif
diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
index 0e30f16149d5..9504169fb37f 100644
--- a/arch/arm64/kvm/pkvm.c
+++ b/arch/arm64/kvm/pkvm.c
@@ -328,7 +328,7 @@ int pkvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
 	u64 pfn = phys >> PAGE_SHIFT;
 	int ret;
 
-	if (size != PAGE_SIZE)
+	if (size != PAGE_SIZE && size != PMD_SIZE)
 		return -EINVAL;
 
 	lockdep_assert_held_write(&kvm->mmu_lock);
-- 
2.49.0.1015.ga840276032-goog