[PATCH v7 05/16] virt: geniezone: Add set_user_memory_region for vm

[Yi-De Wu <yi-de.wu@mediatek.com>]

From: "Yingshiuan Pan" <yingshiuan.pan@mediatek.com>

Direct use of physical memory from VMs is forbidden and designed to be
dictated to the privilege models managed by GenieZone hypervisor for
security reason. With the help of gzvm-ko, the hypervisor would be able
to manipulate memory as objects. And the memory management is highly
integrated with ARM 2-stage translation tables to convert VA to IPA to
PA under proper security measures required by protected VMs.

Signed-off-by: Yingshiuan Pan <yingshiuan.pan@mediatek.com>
Signed-off-by: Jerry Wang <ze-yu.wang@mediatek.com>
Signed-off-by: Yi-De Wu <yi-de.wu@mediatek.com>
Signed-off-by: Liju Chen <liju-clr.chen@mediatek.com>
---
 arch/arm64/geniezone/gzvm_arch_common.h |   2 +
 arch/arm64/geniezone/vm.c               |  34 ++++++++
 drivers/virt/geniezone/Makefile         |   3 +-
 drivers/virt/geniezone/gzvm_mmu.c       | 108 +++++++++++++++++++++++
 drivers/virt/geniezone/gzvm_vm.c        | 110 ++++++++++++++++++++++++
 include/linux/gzvm_drv.h                |  44 ++++++++++
 include/uapi/linux/gzvm.h               |  26 ++++++
 7 files changed, 326 insertions(+), 1 deletion(-)
 create mode 100644 drivers/virt/geniezone/gzvm_mmu.c

diff --git a/arch/arm64/geniezone/gzvm_arch_common.h b/arch/arm64/geniezone/gzvm_arch_common.h
index 68cc6388f4cc..a0268adf3d8f 100644
--- a/arch/arm64/geniezone/gzvm_arch_common.h
+++ b/arch/arm64/geniezone/gzvm_arch_common.h
@@ -11,6 +11,7 @@
 enum {
 	GZVM_FUNC_CREATE_VM = 0,
 	GZVM_FUNC_DESTROY_VM = 1,
+	GZVM_FUNC_SET_MEMREGION = 4,
 	GZVM_FUNC_PROBE = 12,
 	NR_GZVM_FUNC,
 };
@@ -23,6 +24,7 @@ enum {
 
 #define MT_HVC_GZVM_CREATE_VM		GZVM_HCALL_ID(GZVM_FUNC_CREATE_VM)
 #define MT_HVC_GZVM_DESTROY_VM		GZVM_HCALL_ID(GZVM_FUNC_DESTROY_VM)
+#define MT_HVC_GZVM_SET_MEMREGION	GZVM_HCALL_ID(GZVM_FUNC_SET_MEMREGION)
 #define MT_HVC_GZVM_PROBE		GZVM_HCALL_ID(GZVM_FUNC_PROBE)
 
 /**
diff --git a/arch/arm64/geniezone/vm.c b/arch/arm64/geniezone/vm.c
index b9789e2384f6..c051dd6e590f 100644
--- a/arch/arm64/geniezone/vm.c
+++ b/arch/arm64/geniezone/vm.c
@@ -42,6 +42,15 @@ int gzvm_arch_probe(void)
 	return 0;
 }
 
+int gzvm_arch_set_memregion(u16 vm_id, size_t buf_size,
+			    phys_addr_t region)
+{
+	struct arm_smccc_res res;
+
+	return gzvm_hypcall_wrapper(MT_HVC_GZVM_SET_MEMREGION, vm_id,
+				    buf_size, region, 0, 0, 0, 0, &res);
+}
+
 /**
  * gzvm_arch_create_vm() - create vm
  * @vm_type: VM type. Only supports Linux VM now.
@@ -67,3 +76,28 @@ int gzvm_arch_destroy_vm(u16 vm_id)
 	return gzvm_hypcall_wrapper(MT_HVC_GZVM_DESTROY_VM, vm_id, 0, 0, 0, 0,
 				    0, 0, &res);
 }
+
+/**
+ * gzvm_hva_to_pa_arch() - converts hva to pa with arch-specific way
+ * @hva: Host virtual address.
+ *
+ * Return: GZVM_PA_ERR_BAD for translation error
+ */
+u64 gzvm_hva_to_pa_arch(u64 hva)
+{
+	unsigned long flags;
+	u64 par;
+
+	local_irq_save(flags);
+	asm volatile("at s1e1r, %0" :: "r" (hva));
+	isb();
+	par = read_sysreg_par();
+	local_irq_restore(flags);
+
+	if (par & SYS_PAR_EL1_F)
+		return GZVM_PA_ERR_BAD;
+	par = par & PAR_PA47_MASK;
+	if (!par)
+		return GZVM_PA_ERR_BAD;
+	return par;
+}
diff --git a/drivers/virt/geniezone/Makefile b/drivers/virt/geniezone/Makefile
index 066efddc0b9c..43eba5cbbf4e 100644
--- a/drivers/virt/geniezone/Makefile
+++ b/drivers/virt/geniezone/Makefile
@@ -6,5 +6,6 @@
 
 GZVM_DIR ?= ../../../drivers/virt/geniezone
 
-gzvm-y := $(GZVM_DIR)/gzvm_main.o $(GZVM_DIR)/gzvm_vm.o
+gzvm-y := $(GZVM_DIR)/gzvm_main.o $(GZVM_DIR)/gzvm_mmu.o \
+	  $(GZVM_DIR)/gzvm_vm.o
 
diff --git a/drivers/virt/geniezone/gzvm_mmu.c b/drivers/virt/geniezone/gzvm_mmu.c
new file mode 100644
index 000000000000..17d696992d2c
--- /dev/null
+++ b/drivers/virt/geniezone/gzvm_mmu.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2023 MediaTek Inc.
+ */
+
+#include <linux/gzvm_drv.h>
+
+/**
+ * hva_to_pa_fast() - converts hva to pa in generic fast way
+ * @hva: Host virtual address.
+ *
+ * Return: GZVM_PA_ERR_BAD for translation error
+ */
+u64 hva_to_pa_fast(u64 hva)
+{
+	struct page *page[1];
+	u64 pfn;
+
+	if (get_user_page_fast_only(hva, 0, page)) {
+		pfn = page_to_phys(page[0]);
+		put_page((struct page *)page);
+		return pfn;
+	}
+	return GZVM_PA_ERR_BAD;
+}
+
+/**
+ * hva_to_pa_slow() - converts hva to pa in a slow way
+ * @hva: Host virtual address
+ *
+ * This function converts HVA to PA in a slow way because the target hva is not
+ * yet allocated and mapped in the host stage1 page table, we cannot find it
+ * directly from current page table.
+ * Thus, we have to allocate it and this operation is much slower than directly
+ * find via current page table.
+ *
+ * Context: This function may sleep
+ * Return: PA or GZVM_PA_ERR_BAD for translation error
+ */
+u64 hva_to_pa_slow(u64 hva)
+{
+	struct page *page = NULL;
+	u64 pfn = 0;
+	int npages;
+
+	npages = get_user_pages_unlocked(hva, 1, &page, 0);
+	if (npages != 1)
+		return GZVM_PA_ERR_BAD;
+
+	if (page) {
+		pfn = page_to_phys(page);
+		put_page(page);
+		return pfn;
+	}
+
+	return GZVM_PA_ERR_BAD;
+}
+
+static u64 __gzvm_gfn_to_pfn_memslot(struct gzvm_memslot *memslot, u64 gfn)
+{
+	u64 hva, pa;
+
+	hva = gzvm_gfn_to_hva_memslot(memslot, gfn);
+
+	pa = gzvm_hva_to_pa_arch(hva);
+	if (pa != GZVM_PA_ERR_BAD)
+		return PHYS_PFN(pa);
+
+	pa = hva_to_pa_fast(hva);
+	if (pa != GZVM_PA_ERR_BAD)
+		return PHYS_PFN(pa);
+
+	pa = hva_to_pa_slow(hva);
+	if (pa != GZVM_PA_ERR_BAD)
+		return PHYS_PFN(pa);
+
+	return GZVM_PA_ERR_BAD;
+}
+
+/**
+ * gzvm_gfn_to_pfn_memslot() - Translate gfn (guest ipa) to pfn (host pa),
+ *			       result is in @pfn
+ * @memslot: Pointer to struct gzvm_memslot.
+ * @gfn: Guest frame number.
+ * @pfn: Host page frame number.
+ *
+ * Return:
+ * * 0			- Succeed
+ * * -EFAULT		- Failed to convert
+ */
+int gzvm_gfn_to_pfn_memslot(struct gzvm_memslot *memslot, u64 gfn,
+			    u64 *pfn)
+{
+	u64 __pfn;
+
+	if (!memslot)
+		return -EFAULT;
+
+	__pfn = __gzvm_gfn_to_pfn_memslot(memslot, gfn);
+	if (__pfn == GZVM_PA_ERR_BAD) {
+		*pfn = 0;
+		return -EFAULT;
+	}
+
+	*pfn = __pfn;
+
+	return 0;
+}
diff --git a/drivers/virt/geniezone/gzvm_vm.c b/drivers/virt/geniezone/gzvm_vm.c
index d5e850af924a..326cc9e93d92 100644
--- a/drivers/virt/geniezone/gzvm_vm.c
+++ b/drivers/virt/geniezone/gzvm_vm.c
@@ -15,6 +15,115 @@
 static DEFINE_MUTEX(gzvm_list_lock);
 static LIST_HEAD(gzvm_list);
 
+u64 gzvm_gfn_to_hva_memslot(struct gzvm_memslot *memslot, u64 gfn)
+{
+	u64 offset = gfn - memslot->base_gfn;
+
+	return memslot->userspace_addr + offset * PAGE_SIZE;
+}
+
+/**
+ * register_memslot_addr_range() - Register memory region to GenieZone
+ * @gzvm: Pointer to struct gzvm
+ * @memslot: Pointer to struct gzvm_memslot
+ *
+ * Return: 0 for success, negative number for error
+ */
+static int
+register_memslot_addr_range(struct gzvm *gzvm, struct gzvm_memslot *memslot)
+{
+	struct gzvm_memory_region_ranges *region;
+	u32 buf_size = PAGE_SIZE * 2;
+	u64 gfn;
+
+	region = alloc_pages_exact(buf_size, GFP_KERNEL);
+	if (!region)
+		return -ENOMEM;
+
+	region->slot = memslot->slot_id;
+	region->total_pages = memslot->npages;
+	gfn = memslot->base_gfn;
+	region->gpa = PFN_PHYS(gfn);
+
+	if (gzvm_arch_set_memregion(gzvm->vm_id, buf_size,
+				    virt_to_phys(region))) {
+		pr_err("Failed to register memregion to hypervisor\n");
+		free_pages_exact(region, buf_size);
+		return -EFAULT;
+	}
+
+	free_pages_exact(region, buf_size);
+	return 0;
+}
+
+/**
+ * gzvm_vm_ioctl_set_memory_region() - Set memory region of guest
+ * @gzvm: Pointer to struct gzvm.
+ * @mem: Input memory region from user.
+ *
+ * Return: 0 for success, negative number for error
+ *
+ * -EXIO		- The memslot is out-of-range
+ * -EFAULT		- Cannot find corresponding vma
+ * -EINVAL		- Region size and VMA size mismatch
+ */
+static int
+gzvm_vm_ioctl_set_memory_region(struct gzvm *gzvm,
+				struct gzvm_userspace_memory_region *mem)
+{
+	struct vm_area_struct *vma;
+	struct gzvm_memslot *memslot;
+	unsigned long size;
+	__u32 slot;
+
+	slot = mem->slot;
+	if (slot >= GZVM_MAX_MEM_REGION)
+		return -ENXIO;
+	memslot = &gzvm->memslot[slot];
+
+	vma = vma_lookup(gzvm->mm, mem->userspace_addr);
+	if (!vma)
+		return -EFAULT;
+
+	size = vma->vm_end - vma->vm_start;
+	if (size != mem->memory_size)
+		return -EINVAL;
+
+	memslot->base_gfn = __phys_to_pfn(mem->guest_phys_addr);
+	memslot->npages = size >> PAGE_SHIFT;
+	memslot->userspace_addr = mem->userspace_addr;
+	memslot->vma = vma;
+	memslot->flags = mem->flags;
+	memslot->slot_id = mem->slot;
+	return register_memslot_addr_range(gzvm, memslot);
+}
+
+/* gzvm_vm_ioctl() - Ioctl handler of VM FD */
+static long gzvm_vm_ioctl(struct file *filp, unsigned int ioctl,
+			  unsigned long arg)
+{
+	long ret;
+	void __user *argp = (void __user *)arg;
+	struct gzvm *gzvm = filp->private_data;
+
+	switch (ioctl) {
+	case GZVM_SET_USER_MEMORY_REGION: {
+		struct gzvm_userspace_memory_region userspace_mem;
+
+		if (copy_from_user(&userspace_mem, argp, sizeof(userspace_mem))) {
+			ret = -EFAULT;
+			goto out;
+		}
+		ret = gzvm_vm_ioctl_set_memory_region(gzvm, &userspace_mem);
+		break;
+	}
+	default:
+		ret = -ENOTTY;
+	}
+out:
+	return ret;
+}
+
 static void gzvm_destroy_vm(struct gzvm *gzvm)
 {
 	pr_debug("VM-%u is going to be destroyed\n", gzvm->vm_id);
@@ -42,6 +151,7 @@ static int gzvm_vm_release(struct inode *inode, struct file *filp)
 
 static const struct file_operations gzvm_vm_fops = {
 	.release        = gzvm_vm_release,
+	.unlocked_ioctl = gzvm_vm_ioctl,
 	.llseek		= noop_llseek,
 };
 
diff --git a/include/linux/gzvm_drv.h b/include/linux/gzvm_drv.h
index f1dce23838e4..aa1eaf4d43b4 100644
--- a/include/linux/gzvm_drv.h
+++ b/include/linux/gzvm_drv.h
@@ -7,9 +7,16 @@
 #define __GZVM_DRV_H__
 
 #include <linux/list.h>
+#include <linux/mm.h>
 #include <linux/mutex.h>
 #include <linux/gzvm.h>
 
+/*
+ * For the normal physical address, the highest 12 bits should be zero, so we
+ * can mask bit 62 ~ bit 52 to indicate the error physical address
+ */
+#define GZVM_PA_ERR_BAD (0x7ffULL << 52)
+
 #define INVALID_VM_ID   0xffff
 
 /*
@@ -27,10 +34,39 @@
  * The following data structures are for data transferring between driver and
  * hypervisor, and they're aligned with hypervisor definitions
  */
+#define GZVM_MAX_MEM_REGION	10
+
+/* struct mem_region_addr_range - Identical to ffa memory constituent */
+struct mem_region_addr_range {
+	/* the base IPA of the constituent memory region, aligned to 4 kiB */
+	__u64 address;
+	/* the number of 4 kiB pages in the constituent memory region. */
+	__u32 pg_cnt;
+	__u32 reserved;
+};
+
+struct gzvm_memory_region_ranges {
+	__u32 slot;
+	__u32 constituent_cnt;
+	__u64 total_pages;
+	__u64 gpa;
+	struct mem_region_addr_range constituents[];
+};
+
+/* struct gzvm_memslot - VM's memory slot descriptor */
+struct gzvm_memslot {
+	u64 base_gfn;			/* begin of guest page frame */
+	unsigned long npages;		/* number of pages this slot covers */
+	unsigned long userspace_addr;	/* corresponding userspace va */
+	struct vm_area_struct *vma;	/* vma related to this userspace addr */
+	u32 flags;
+	u32 slot_id;
+};
 
 struct gzvm {
 	/* userspace tied to this vm */
 	struct mm_struct *mm;
+	struct gzvm_memslot memslot[GZVM_MAX_MEM_REGION];
 	/* lock for list_add*/
 	struct mutex lock;
 	struct list_head vm_list;
@@ -45,7 +81,15 @@ void gzvm_destroy_all_vms(void);
 
 /* arch-dependant functions */
 int gzvm_arch_probe(void);
+int gzvm_arch_set_memregion(u16 vm_id, size_t buf_size,
+			    phys_addr_t region);
 int gzvm_arch_create_vm(unsigned long vm_type);
 int gzvm_arch_destroy_vm(u16 vm_id);
 
+u64 gzvm_hva_to_pa_arch(u64 hva);
+u64 hva_to_pa_fast(u64 hva);
+u64 hva_to_pa_slow(u64 hva);
+int gzvm_gfn_to_pfn_memslot(struct gzvm_memslot *memslot, u64 gfn, u64 *pfn);
+u64 gzvm_gfn_to_hva_memslot(struct gzvm_memslot *memslot, u64 gfn);
+
 #endif /* __GZVM_DRV_H__ */
diff --git a/include/uapi/linux/gzvm.h b/include/uapi/linux/gzvm.h
index c26c7720fab7..d2d5e6cfc2c9 100644
--- a/include/uapi/linux/gzvm.h
+++ b/include/uapi/linux/gzvm.h
@@ -22,4 +22,30 @@
 /* ioctls for /dev/gzvm fds */
 #define GZVM_CREATE_VM             _IO(GZVM_IOC_MAGIC,   0x01) /* Returns a Geniezone VM fd */
 
+/* ioctls for VM fds */
+/* for GZVM_SET_MEMORY_REGION */
+struct gzvm_memory_region {
+	__u32 slot;
+	__u32 flags;
+	__u64 guest_phys_addr;
+	__u64 memory_size; /* bytes */
+};
+
+#define GZVM_SET_MEMORY_REGION     _IOW(GZVM_IOC_MAGIC,  0x40, \
+					struct gzvm_memory_region)
+
+/* for GZVM_SET_USER_MEMORY_REGION */
+struct gzvm_userspace_memory_region {
+	__u32 slot;
+	__u32 flags;
+	__u64 guest_phys_addr;
+	/* bytes */
+	__u64 memory_size;
+	/* start of the userspace allocated memory */
+	__u64 userspace_addr;
+};
+
+#define GZVM_SET_USER_MEMORY_REGION _IOW(GZVM_IOC_MAGIC, 0x46, \
+					 struct gzvm_userspace_memory_region)
+
 #endif /* __GZVM_H__ */
-- 
2.18.0