linux-kernel - [PATCH v5 25/27] iommu/arm-smmu-v3-kvm: Support io-pgtable

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Message-ID: <20251117184815.1027271-26-smostafa@google.com>
Date: Mon, 17 Nov 2025 18:48:12 +0000
From: Mostafa Saleh <smostafa@...gle.com>
To: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	kvmarm@...ts.linux.dev, iommu@...ts.linux.dev
Cc: catalin.marinas@....com, will@...nel.org, maz@...nel.org, 
	oliver.upton@...ux.dev, joey.gouly@....com, suzuki.poulose@....com, 
	yuzenghui@...wei.com, joro@...tes.org, jean-philippe@...aro.org, jgg@...pe.ca, 
	praan@...gle.com, danielmentz@...gle.com, mark.rutland@....com, 
	qperret@...gle.com, tabba@...gle.com, Mostafa Saleh <smostafa@...gle.com>
Subject: [PATCH v5 25/27] iommu/arm-smmu-v3-kvm: Support io-pgtable

Add hooks needed to support io-pgtable-arm, mostly about
memory allocation.

Also add a function to allocate s2 64 bit page table.

Signed-off-by: Mostafa Saleh <smostafa@...gle.com>
---
 arch/arm64/kvm/hyp/nvhe/Makefile              |  4 +-
 .../arm/arm-smmu-v3/pkvm/io-pgtable-arm-hyp.c | 68 +++++++++++++++++++
 drivers/iommu/io-pgtable-arm.c                |  2 +-
 drivers/iommu/io-pgtable-arm.h                | 11 +++
 4 files changed, 83 insertions(+), 2 deletions(-)
 create mode 100644 drivers/iommu/arm/arm-smmu-v3/pkvm/io-pgtable-arm-hyp.c

diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index 197685817546..99c2ce941146 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -35,7 +35,9 @@ hyp-obj-y += $(lib-objs)
 HYP_SMMU_V3_DRV_PATH = ../../../../../drivers/iommu/arm/arm-smmu-v3
 
 hyp-obj-$(CONFIG_ARM_SMMU_V3_PKVM) += $(HYP_SMMU_V3_DRV_PATH)/pkvm/arm-smmu-v3.o \
-	$(HYP_SMMU_V3_DRV_PATH)/arm-smmu-v3-common-lib.o
+	$(HYP_SMMU_V3_DRV_PATH)/arm-smmu-v3-common-lib.o \
+	$(HYP_SMMU_V3_DRV_PATH)/pkvm/io-pgtable-arm-hyp.o \
+	$(HYP_SMMU_V3_DRV_PATH)/../../io-pgtable-arm.o
 
 ##
 ## Build rules for compiling nVHE hyp code
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/io-pgtable-arm-hyp.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/io-pgtable-arm-hyp.c
new file mode 100644
index 000000000000..fc2006dc0b82
--- /dev/null
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/io-pgtable-arm-hyp.c
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2022 Arm Ltd.
+ */
+#include <nvhe/iommu.h>
+
+#include <linux/io-pgtable.h>
+#include "../../../io-pgtable-arm.h"
+
+struct io_pgtable_ops *kvm_alloc_io_pgtable_ops(enum io_pgtable_fmt fmt,
+						struct io_pgtable_cfg *cfg,
+						void *cookie)
+{
+	struct io_pgtable *iop;
+
+	if (fmt != ARM_64_LPAE_S2)
+		return NULL;
+
+	iop = arm_64_lpae_alloc_pgtable_s2(cfg, cookie);
+	if (!iop)
+		return NULL;
+
+	iop->fmt	= fmt;
+	iop->cookie	= cookie;
+	iop->cfg	= *cfg;
+
+	return &iop->ops;
+}
+
+void *__arm_lpae_alloc_pages(size_t size, gfp_t gfp,
+			     struct io_pgtable_cfg *cfg, void *cookie)
+{
+	void *addr;
+
+	addr = kvm_iommu_donate_pages(get_order(size));
+
+	if (addr && !cfg->coherent_walk)
+		kvm_flush_dcache_to_poc(addr, size);
+
+	return addr;
+}
+
+void __arm_lpae_free_pages(void *addr, size_t size, struct io_pgtable_cfg *cfg,
+			   void *cookie)
+{
+	if (!cfg->coherent_walk)
+		kvm_flush_dcache_to_poc(addr, size);
+
+	kvm_iommu_reclaim_pages(addr);
+}
+
+void __arm_lpae_sync_pte(arm_lpae_iopte *ptep, int num_entries,
+			 struct io_pgtable_cfg *cfg)
+{
+	if (!cfg->coherent_walk)
+		kvm_flush_dcache_to_poc(ptep, sizeof(*ptep) * num_entries);
+}
+
+/* At the moment this is only used once, so rounding up to a page is not really a problem. */
+void *__arm_lpae_alloc_data(size_t size, gfp_t gfp)
+{
+	return kvm_iommu_donate_pages(get_order(size));
+}
+
+void __arm_lpae_free_data(void *p)
+{
+	return kvm_iommu_reclaim_pages(p);
+}
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 377c15bc8350..dbb1a58a5ce6 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -980,7 +980,7 @@ arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie)
 	return NULL;
 }
 
-static struct io_pgtable *
+struct io_pgtable *
 arm_64_lpae_alloc_pgtable_s2(struct io_pgtable_cfg *cfg, void *cookie)
 {
 	u64 sl;
diff --git a/drivers/iommu/io-pgtable-arm.h b/drivers/iommu/io-pgtable-arm.h
index 62d127dae1c2..742a6ed9ae3c 100644
--- a/drivers/iommu/io-pgtable-arm.h
+++ b/drivers/iommu/io-pgtable-arm.h
@@ -41,9 +41,20 @@ void *__arm_lpae_alloc_pages(size_t size, gfp_t gfp,
 			     void *cookie);
 void *__arm_lpae_alloc_data(size_t size, gfp_t gfp);
 void __arm_lpae_free_data(void *p);
+struct io_pgtable *
+arm_64_lpae_alloc_pgtable_s2(struct io_pgtable_cfg *cfg, void *cookie);
 #ifndef __KVM_NVHE_HYPERVISOR__
 #define __arm_lpae_virt_to_phys	__pa
 #define __arm_lpae_phys_to_virt	__va
+#else
+#include <nvhe/memory.h>
+#define __arm_lpae_virt_to_phys	hyp_virt_to_phys
+#define __arm_lpae_phys_to_virt	hyp_phys_to_virt
+#undef WARN_ONCE
+#define WARN_ONCE(condition, format...)	WARN_ON(1)
+struct io_pgtable_ops *kvm_alloc_io_pgtable_ops(enum io_pgtable_fmt fmt,
+						struct io_pgtable_cfg *cfg,
+						void *cookie);
 #endif /* !__KVM_NVHE_HYPERVISOR__ */
 
 #endif /* IO_PGTABLE_ARM_H_ */
-- 
2.52.0.rc1.455.g30608eb744-goog