[RFC PATCH v2 31/58] KVM: arm64: smmu-v3: Support io-pgtable

[Mostafa Saleh <smostafa@google.com>]

From: Jean-Philippe Brucker <jean-philippe@linaro.org>

Implement the hypervisor version of io-pgtable allocation functions,
mirroring drivers/iommu/io-pgtable-arm.c. Page allocation uses the
IOMMU pool filled by the host.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
 arch/arm64/kvm/hyp/nvhe/Makefile              |   2 +
 .../arm64/kvm/hyp/nvhe/iommu/io-pgtable-arm.c | 153 ++++++++++++++++++
 include/linux/io-pgtable-arm.h                |  11 ++
 3 files changed, 166 insertions(+)
 create mode 100644 arch/arm64/kvm/hyp/nvhe/iommu/io-pgtable-arm.c

diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index edfd8a11ac90..e4f662b1447f 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -17,6 +17,8 @@ hyp-obj-$(CONFIG_MODULES) += modules.o
 hyp-obj-y += $(lib-objs)
 
 hyp-obj-$(CONFIG_ARM_SMMU_V3_PKVM) += iommu/arm-smmu-v3.o
+hyp-obj-$(CONFIG_ARM_SMMU_V3_PKVM) += iommu/io-pgtable-arm.o \
+	../../../../../drivers/iommu/io-pgtable-arm-common.o
 
 $(obj)/hyp.lds: $(src)/hyp.lds.S FORCE
 	$(call if_changed_dep,cpp_lds_S)
diff --git a/arch/arm64/kvm/hyp/nvhe/iommu/io-pgtable-arm.c b/arch/arm64/kvm/hyp/nvhe/iommu/io-pgtable-arm.c
new file mode 100644
index 000000000000..aa5bf7c0ed03
--- /dev/null
+++ b/arch/arm64/kvm/hyp/nvhe/iommu/io-pgtable-arm.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2022 Arm Ltd.
+ */
+#include <asm/kvm_hyp.h>
+#include <asm/kvm_mmu.h>
+#include <kvm/arm_smmu_v3.h>
+#include <linux/types.h>
+#include <linux/gfp_types.h>
+#include <linux/io-pgtable-arm.h>
+
+#include <nvhe/alloc.h>
+#include <nvhe/iommu.h>
+#include <nvhe/mem_protect.h>
+
+int arm_lpae_map_exists(void)
+{
+	return -EEXIST;
+}
+
+int arm_lpae_unmap_empty(void)
+{
+	return -EEXIST;
+}
+
+void *__arm_lpae_alloc_pages(size_t size, gfp_t gfp,
+			     struct io_pgtable_cfg *cfg, void *cookie)
+{
+	void *addr;
+
+	if (!PAGE_ALIGNED(size))
+		return NULL;
+
+	addr = kvm_iommu_donate_pages(get_order(size), 0);
+
+	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)
+{
+	u8 order;
+
+	/*
+	 * It's guaranteed all allocations are aligned, but core code
+	 * might free PGD with it's actual size.
+	 */
+	order = get_order(PAGE_ALIGN(size));
+
+	if (!cfg->coherent_walk)
+		kvm_flush_dcache_to_poc(addr, size);
+
+	kvm_iommu_reclaim_pages(addr, order);
+}
+
+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);
+}
+
+static int kvm_arm_io_pgtable_init(struct io_pgtable_cfg *cfg,
+				   struct arm_lpae_io_pgtable *data)
+{
+	int ret = -EINVAL;
+
+	if (cfg->fmt == ARM_64_LPAE_S2)
+		ret = arm_lpae_init_pgtable_s2(cfg, data);
+	else if (cfg->fmt == ARM_64_LPAE_S1)
+		ret = arm_lpae_init_pgtable_s1(cfg, data);
+
+	if (ret)
+		return ret;
+
+	data->iop.cfg = *cfg;
+	data->iop.fmt	= cfg->fmt;
+
+	return 0;
+}
+
+struct io_pgtable *kvm_arm_io_pgtable_alloc(struct io_pgtable_cfg *cfg,
+					    void *cookie,
+					    int *out_ret)
+{
+	size_t pgd_size, alignment;
+	struct arm_lpae_io_pgtable *data;
+	int ret;
+
+	data = hyp_alloc(sizeof(*data));
+	if (!data) {
+		*out_ret = hyp_alloc_errno();
+		return NULL;
+	}
+
+	ret = kvm_arm_io_pgtable_init(cfg, data);
+	if (ret)
+		goto out_free;
+
+	pgd_size = PAGE_ALIGN(ARM_LPAE_PGD_SIZE(data));
+	data->pgd = __arm_lpae_alloc_pages(pgd_size, 0, &data->iop.cfg, cookie);
+	if (!data->pgd) {
+		ret = -ENOMEM;
+		goto out_free;
+	}
+	/*
+	 * If it has eight or more entries, the table must be aligned on
+	 * its size. Otherwise 64 bytes.
+	 */
+	alignment = max(pgd_size, 8 * sizeof(arm_lpae_iopte));
+	if (!IS_ALIGNED(hyp_virt_to_phys(data->pgd), alignment)) {
+		__arm_lpae_free_pages(data->pgd, pgd_size,
+				      &data->iop.cfg, cookie);
+		ret = -EINVAL;
+		goto out_free;
+	}
+
+	data->iop.cookie = cookie;
+	if (cfg->fmt == ARM_64_LPAE_S2)
+		data->iop.cfg.arm_lpae_s2_cfg.vttbr = __arm_lpae_virt_to_phys(data->pgd);
+	else if (cfg->fmt == ARM_64_LPAE_S1)
+		data->iop.cfg.arm_lpae_s1_cfg.ttbr = __arm_lpae_virt_to_phys(data->pgd);
+
+	if (!data->iop.cfg.coherent_walk)
+		kvm_flush_dcache_to_poc(data->pgd, pgd_size);
+
+	/* Ensure the empty pgd is visible before any actual TTBR write */
+	wmb();
+
+	*out_ret = 0;
+	return &data->iop;
+out_free:
+	hyp_free(data);
+	*out_ret = ret;
+	return NULL;
+}
+
+int kvm_arm_io_pgtable_free(struct io_pgtable *iopt)
+{
+	struct arm_lpae_io_pgtable *data = io_pgtable_to_data(iopt);
+	size_t pgd_size = ARM_LPAE_PGD_SIZE(data);
+
+	if (!data->iop.cfg.coherent_walk)
+		kvm_flush_dcache_to_poc(data->pgd, pgd_size);
+
+	io_pgtable_tlb_flush_all(iopt);
+	__arm_lpae_free_pgtable(data, data->start_level, data->pgd);
+	hyp_free(data);
+	return 0;
+}
diff --git a/include/linux/io-pgtable-arm.h b/include/linux/io-pgtable-arm.h
index 337e9254fdbd..88922314157d 100644
--- a/include/linux/io-pgtable-arm.h
+++ b/include/linux/io-pgtable-arm.h
@@ -191,8 +191,19 @@ static inline bool iopte_table(arm_lpae_iopte pte, int lvl)
 	return iopte_type(pte) == ARM_LPAE_PTE_TYPE_TABLE;
 }
 
+#ifdef __KVM_NVHE_HYPERVISOR__
+#include <nvhe/memory.h>
+#define __arm_lpae_virt_to_phys	hyp_virt_to_phys
+#define __arm_lpae_phys_to_virt	hyp_phys_to_virt
+
+struct io_pgtable *kvm_arm_io_pgtable_alloc(struct io_pgtable_cfg *cfg,
+					    void *cookie,
+					    int *out_ret);
+int kvm_arm_io_pgtable_free(struct io_pgtable *iop);
+#else
 #define __arm_lpae_virt_to_phys	__pa
 #define __arm_lpae_phys_to_virt	__va
+#endif
 
 /* Generic functions */
 void __arm_lpae_free_pgtable(struct arm_lpae_io_pgtable *data, int lvl,
-- 
2.47.0.338.g60cca15819-goog