[PATCH v6 05/15] virt: geniezone: Add set_user_memory_region for vm

From: Yi-De Wu
Date: Tue Sep 19 2023 - 07:13:49 EST

From: "Yingshiuan Pan" <yingshiuan.pan@xxxxxxxxxxxx>

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@xxxxxxxxxxxx>
Signed-off-by: Jerry Wang <ze-yu.wang@xxxxxxxxxxxx>
Signed-off-by: Liju Chen <liju-clr.chen@xxxxxxxxxxxx>
Signed-off-by: Yi-De Wu <yi-de.wu@xxxxxxxxxxxx>
---
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 | 182 ++++++++++++++++++++++++
include/linux/gzvm_drv.h | 44 ++++++
include/uapi/linux/gzvm.h | 26 ++++
7 files changed, 398 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 f4439e43b018..14d288299435 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 a17bc628a496..47b41ac47f7a 100644
--- a/arch/arm64/geniezone/vm.c
+++ b/arch/arm64/geniezone/vm.c
@@ -24,6 +24,15 @@ 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.
@@ -49,3 +58,28 @@ 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..e0751811cce6 100644
--- a/drivers/virt/geniezone/gzvm_vm.c
+++ b/drivers/virt/geniezone/gzvm_vm.c
@@ -15,6 +15,187 @@
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;
+}
+
+/**
+ * fill_constituents() - Populate pa to buffer until full
+ * @consti: Pointer to struct mem_region_addr_range.
+ * @consti_cnt: Constituent count.
+ * @max_nr_consti: Maximum number of constituent count.
+ * @gfn: Guest frame number.
+ * @total_pages: Total page numbers.
+ * @slot: Pointer to struct gzvm_memslot.
+ *
+ * Return: how many pages we've fill in, negative if error
+ */
+static int fill_constituents(struct mem_region_addr_range *consti,
+ int *consti_cnt, int max_nr_consti, u64 gfn,
+ u32 total_pages, struct gzvm_memslot *slot)
+{
+ u64 pfn, prev_pfn, gfn_end;
+ int nr_pages = 1;
+ int i = 0;
+
+ if (unlikely(total_pages == 0))
+ return -EINVAL;
+ gfn_end = gfn + total_pages;
+
+ /* entry 0 */
+ if (gzvm_gfn_to_pfn_memslot(slot, gfn, &pfn) != 0)
+ return -EFAULT;
+ consti[0].address = PFN_PHYS(pfn);
+ consti[0].pg_cnt = 1;
+ gfn++;
+ prev_pfn = pfn;
+
+ while (i < max_nr_consti && gfn < gfn_end) {
+ if (gzvm_gfn_to_pfn_memslot(slot, gfn, &pfn) != 0)
+ return -EFAULT;
+ if (pfn == (prev_pfn + 1)) {
+ consti[i].pg_cnt++;
+ } else {
+ i++;
+ if (i >= max_nr_consti)
+ break;
+ consti[i].address = PFN_PHYS(pfn);
+ consti[i].pg_cnt = 1;
+ }
+ prev_pfn = pfn;
+ gfn++;
+ nr_pages++;
+ }
+ if (i != max_nr_consti)
+ i++;
+ *consti_cnt = i;
+
+ return nr_pages;
+}
+
+/**
+ * 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;
+ int max_nr_consti, remain_pages;
+ u64 gfn, gfn_end;
+
+ region = alloc_pages_exact(buf_size, GFP_KERNEL);
+ if (!region)
+ return -ENOMEM;
+ max_nr_consti = (buf_size - sizeof(*region)) /
+ sizeof(struct mem_region_addr_range);
+
+ region->slot = memslot->slot_id;
+ remain_pages = memslot->npages;
+ gfn = memslot->base_gfn;
+ gfn_end = gfn + remain_pages;
+ while (gfn < gfn_end) {
+ int nr_pages = fill_constituents(region->constituents,
+ &region->constituent_cnt,
+ max_nr_consti, gfn,
+ remain_pages, memslot);
+ if (nr_pages < 0) {
+ pr_err("Failed to fill constituents\n");
+ free_pages_exact(region, buf_size);
+ return nr_pages;
+ }
+ region->gpa = PFN_PHYS(gfn);
+ region->total_pages = nr_pages;
+
+ remain_pages -= nr_pages;
+ gfn += nr_pages;
+
+ 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 +223,7 @@ 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