On 6/13/23 12:20 PM, Elliot Berman wrote:
When launching a virtual machine, Gunyah userspace allocates memory for
the guest and informs Gunyah about these memory regions through
SET_USER_MEMORY_REGION ioctl.
Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@xxxxxxxxxxx>
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@xxxxxxxxxxx>
Signed-off-by: Elliot Berman <quic_eberman@xxxxxxxxxxx>
I have one trivial comment below. This patch adds some complexity
but this time around I'm going to assume I checked those things
in some detail previously. This time I'm doing more of a scan
through the patch and I find it looks good. (If you want me to
spend more time on this, say so.)
Reviewed-by: Alex Elder <elder@xxxxxxxxxx>
---
drivers/virt/gunyah/Makefile | 2 +-
drivers/virt/gunyah/vm_mgr.c | 59 +++++++-
drivers/virt/gunyah/vm_mgr.h | 26 ++++
drivers/virt/gunyah/vm_mgr_mm.c | 232 ++++++++++++++++++++++++++++++++
include/uapi/linux/gunyah.h | 37 +++++
5 files changed, 352 insertions(+), 4 deletions(-)
create mode 100644 drivers/virt/gunyah/vm_mgr_mm.c
diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
index e47e25895299c..bacf78b8fa337 100644
--- a/drivers/virt/gunyah/Makefile
+++ b/drivers/virt/gunyah/Makefile
@@ -1,4 +1,4 @@
# SPDX-License-Identifier: GPL-2.0
-gunyah-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o
+gunyah-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o vm_mgr_mm.o
obj-$(CONFIG_GUNYAH) += gunyah.o
diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c
index a43401cb34f7d..297427952b8c7 100644
--- a/drivers/virt/gunyah/vm_mgr.c
+++ b/drivers/virt/gunyah/vm_mgr.c
@@ -15,6 +15,8 @@
#include "vm_mgr.h"
+static void gh_vm_free(struct work_struct *work);
+
static __must_check struct gh_vm *gh_vm_alloc(struct gh_rm *rm)
{
struct gh_vm *ghvm;
@@ -26,20 +28,72 @@ static __must_check struct gh_vm *gh_vm_alloc(struct gh_rm *rm)
ghvm->parent = gh_rm_get(rm);
ghvm->rm = rm;
+ mmgrab(current->mm);
+ ghvm->mm = current->mm;
+ mutex_init(&ghvm->mm_lock);
+ INIT_LIST_HEAD(&ghvm->memory_mappings);
+ INIT_WORK(&ghvm->free_work, gh_vm_free);
+
return ghvm;
}
-static int gh_vm_release(struct inode *inode, struct file *filp)
+static long gh_vm_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
struct gh_vm *ghvm = filp->private_data;
+ void __user *argp = (void __user *)arg;
+ long r;
Don't you use "ret" for return values most of the time?
(Not a big deal, maybe there's another reason you used
"r" here.)
+
+ switch (cmd) {
+ case GH_VM_SET_USER_MEM_REGION: {
+ struct gh_userspace_memory_region region;
+
+ /* only allow owner task to add memory */
+ if (ghvm->mm != current->mm)
+ return -EPERM;
+
+ if (copy_from_user(®ion, argp, sizeof(region)))
+ return -EFAULT;
+
+ /* All other flag bits are reserved for future use */
+ if (region.flags & ~(GH_MEM_ALLOW_READ | GH_MEM_ALLOW_WRITE | GH_MEM_ALLOW_EXEC))
+ return -EINVAL;
+
+ r = gh_vm_mem_alloc(ghvm, ®ion);
+ break;
+ }
+ default:
+ r = -ENOTTY;
+ break;
+ }
+ return r;
+}
+
+static void gh_vm_free(struct work_struct *work)
+{
+ struct gh_vm *ghvm = container_of(work, struct gh_vm, free_work);
+
+ gh_vm_mem_reclaim(ghvm);
gh_rm_put(ghvm->rm);
+ mmdrop(ghvm->mm);
kfree(ghvm);
+}
+
+static int gh_vm_release(struct inode *inode, struct file *filp)
+{
+ struct gh_vm *ghvm = filp->private_data;
+
+ /* VM will be reset and make RM calls which can interruptible sleep.
+ * Defer to a work so this thread can receive signal.
+ */
+ schedule_work(&ghvm->free_work);
return 0;
}
static const struct file_operations gh_vm_fops = {
.owner = THIS_MODULE,
+ .unlocked_ioctl = gh_vm_ioctl,
+ .compat_ioctl = compat_ptr_ioctl,
.release = gh_vm_release,
.llseek = noop_llseek,
};
@@ -77,8 +131,7 @@ static long gh_dev_ioctl_create_vm(struct gh_rm *rm, unsigned long arg)
err_put_fd:
put_unused_fd(fd);
err_destroy_vm:
- gh_rm_put(ghvm->rm);
- kfree(ghvm);
+ gh_vm_free(&ghvm->free_work);
return err;
}
diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h
index 1e94b58d7d34d..434ef9f662a7a 100644
--- a/drivers/virt/gunyah/vm_mgr.h
+++ b/drivers/virt/gunyah/vm_mgr.h
@@ -7,14 +7,40 @@
#define _GH_VM_MGR_H
#include <linux/gunyah_rsc_mgr.h>
+#include <linux/list.h>
+#include <linux/miscdevice.h>
+#include <linux/mutex.h>
#include <uapi/linux/gunyah.h>
long gh_dev_vm_mgr_ioctl(struct gh_rm *rm, unsigned int cmd, unsigned long arg);
+enum gh_vm_mem_share_type {
+ VM_MEM_SHARE,
+ VM_MEM_LEND,
+};
+
+struct gh_vm_mem {
+ struct list_head list;
+ enum gh_vm_mem_share_type share_type;
+ struct gh_rm_mem_parcel parcel;
+
+ __u64 guest_phys_addr;
+ struct page **pages;
+ unsigned long npages;
+};
+
struct gh_vm {
struct gh_rm *rm;
struct device *parent;
+
+ struct work_struct free_work;
+ struct mm_struct *mm; /* userspace tied to this vm */
+ struct mutex mm_lock;
+ struct list_head memory_mappings;
};
+int gh_vm_mem_alloc(struct gh_vm *ghvm, struct gh_userspace_memory_region *region);
+void gh_vm_mem_reclaim(struct gh_vm *ghvm);
+
#endif
diff --git a/drivers/virt/gunyah/vm_mgr_mm.c b/drivers/virt/gunyah/vm_mgr_mm.c
new file mode 100644
index 0000000000000..6974607f02edd
--- /dev/null
+++ b/drivers/virt/gunyah/vm_mgr_mm.c
@@ -0,0 +1,232 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#define pr_fmt(fmt) "gh_vm_mgr: " fmt
+
+#include <linux/gunyah_rsc_mgr.h>
+#include <linux/mm.h>
+
+#include <uapi/linux/gunyah.h>
+
+#include "vm_mgr.h"
+
+static bool pages_are_mergeable(struct page *a, struct page *b)
+{
+ return page_to_pfn(a) + 1 == page_to_pfn(b);
+}
+
+static bool gh_vm_mem_overlap(struct gh_vm_mem *a, u64 addr, u64 size)
+{
+ u64 a_end = a->guest_phys_addr + (a->npages << PAGE_SHIFT);
+ u64 end = addr + size;
+
+ return a->guest_phys_addr < end && addr < a_end;
+}
+
+static struct gh_vm_mem *__gh_vm_mem_find_by_label(struct gh_vm *ghvm, u32 label)
+ __must_hold(&ghvm->mm_lock)
+{
+ struct gh_vm_mem *mapping;
+
+ list_for_each_entry(mapping, &ghvm->memory_mappings, list)
+ if (mapping->parcel.label == label)
+ return mapping;
+
+ return NULL;
+}
+
+static void gh_vm_mem_reclaim_mapping(struct gh_vm *ghvm, struct gh_vm_mem *mapping)
+ __must_hold(&ghvm->mm_lock)
+{
+ int ret = 0;
+
+ if (mapping->parcel.mem_handle != GH_MEM_HANDLE_INVAL) {
+ ret = gh_rm_mem_reclaim(ghvm->rm, &mapping->parcel);
+ if (ret)
+ pr_warn("Failed to reclaim memory parcel for label %d: %d\n",
+ mapping->parcel.label, ret);
+ }
+
+ if (!ret) {
+ unpin_user_pages(mapping->pages, mapping->npages);
+ account_locked_vm(ghvm->mm, mapping->npages, false);
+ }
+
+ kfree(mapping->pages);
+ kfree(mapping->parcel.acl_entries);
+ kfree(mapping->parcel.mem_entries);
+
+ list_del(&mapping->list);
+}
+
+void gh_vm_mem_reclaim(struct gh_vm *ghvm)
+{
+ struct gh_vm_mem *mapping, *tmp;
+
+ mutex_lock(&ghvm->mm_lock);
+
+ list_for_each_entry_safe(mapping, tmp, &ghvm->memory_mappings, list) {
+ gh_vm_mem_reclaim_mapping(ghvm, mapping);
+ kfree(mapping);
+ }
+
+ mutex_unlock(&ghvm->mm_lock);
+}
+
+int gh_vm_mem_alloc(struct gh_vm *ghvm, struct gh_userspace_memory_region *region)
+{
+ struct gh_vm_mem *mapping, *tmp_mapping;
+ struct page *curr_page, *prev_page;
+ struct gh_rm_mem_parcel *parcel;
+ int i, j, pinned, ret = 0;
+ unsigned int gup_flags;
+ size_t entry_size;
+ u16 vmid;
+
+ if (!region->memory_size || !PAGE_ALIGNED(region->memory_size) ||
+ !PAGE_ALIGNED(region->userspace_addr) ||
+ !PAGE_ALIGNED(region->guest_phys_addr))
+ return -EINVAL;
+
+ if (overflows_type(region->guest_phys_addr + region->memory_size, u64))
+ return -EOVERFLOW;
+
+ ret = mutex_lock_interruptible(&ghvm->mm_lock);
+ if (ret)
+ return ret;
+
+ mapping = __gh_vm_mem_find_by_label(ghvm, region->label);
+ if (mapping) {
+ ret = -EEXIST;
+ goto unlock;
+ }
+
+ list_for_each_entry(tmp_mapping, &ghvm->memory_mappings, list) {
+ if (gh_vm_mem_overlap(tmp_mapping, region->guest_phys_addr,
+ region->memory_size)) {
+ ret = -EEXIST;
+ goto unlock;
+ }
+ }
+
+ mapping = kzalloc(sizeof(*mapping), GFP_KERNEL_ACCOUNT);
+ if (!mapping) {
+ ret = -ENOMEM;
+ goto unlock;
+ }
+
+ mapping->guest_phys_addr = region->guest_phys_addr;
+ mapping->npages = region->memory_size >> PAGE_SHIFT;
+ parcel = &mapping->parcel;
+ parcel->label = region->label;
+ parcel->mem_handle = GH_MEM_HANDLE_INVAL; /* to be filled later by mem_share/mem_lend */
+ parcel->mem_type = GH_RM_MEM_TYPE_NORMAL;
+
+ ret = account_locked_vm(ghvm->mm, mapping->npages, true);
+ if (ret)
+ goto free_mapping;
+
+ mapping->pages = kcalloc(mapping->npages, sizeof(*mapping->pages), GFP_KERNEL_ACCOUNT);
+ if (!mapping->pages) {
+ ret = -ENOMEM;
+ mapping->npages = 0; /* update npages for reclaim */
+ goto unlock_pages;
+ }
+
+ gup_flags = FOLL_LONGTERM;
+ if (region->flags & GH_MEM_ALLOW_WRITE)
+ gup_flags |= FOLL_WRITE;
+
+ pinned = pin_user_pages_fast(region->userspace_addr, mapping->npages,
+ gup_flags, mapping->pages);
+ if (pinned < 0) {
+ ret = pinned;
+ goto free_pages;
+ } else if (pinned != mapping->npages) {
+ ret = -EFAULT;
+ mapping->npages = pinned; /* update npages for reclaim */
+ goto unpin_pages;
+ }
+
+ parcel->n_acl_entries = 2;
+ mapping->share_type = VM_MEM_SHARE;
+ parcel->acl_entries = kcalloc(parcel->n_acl_entries, sizeof(*parcel->acl_entries),
+ GFP_KERNEL);
+ if (!parcel->acl_entries) {
+ ret = -ENOMEM;
+ goto unpin_pages;
+ }
+
+ /* acl_entries[0].vmid will be this VM's vmid. We'll fill it when the
+ * VM is starting and we know the VM's vmid.
+ */
+ if (region->flags & GH_MEM_ALLOW_READ)
+ parcel->acl_entries[0].perms |= GH_RM_ACL_R;
+ if (region->flags & GH_MEM_ALLOW_WRITE)
+ parcel->acl_entries[0].perms |= GH_RM_ACL_W;
+ if (region->flags & GH_MEM_ALLOW_EXEC)
+ parcel->acl_entries[0].perms |= GH_RM_ACL_X;
+
+ ret = gh_rm_get_vmid(ghvm->rm, &vmid);
+ if (ret)
+ goto free_acl;
+
+ parcel->acl_entries[1].vmid = cpu_to_le16(vmid);
+ /* Host assumed to have all these permissions. Gunyah will not
+ * grant new permissions if host actually had less than RWX
+ */
+ parcel->acl_entries[1].perms = GH_RM_ACL_R | GH_RM_ACL_W | GH_RM_ACL_X;
+
+ parcel->n_mem_entries = 1;
+ for (i = 1; i < mapping->npages; i++) {
+ if (!pages_are_mergeable(mapping->pages[i - 1], mapping->pages[i]))
+ parcel->n_mem_entries++;
+ }
+
+ parcel->mem_entries = kcalloc(parcel->n_mem_entries,
+ sizeof(parcel->mem_entries[0]),
+ GFP_KERNEL_ACCOUNT);
+ if (!parcel->mem_entries) {
+ ret = -ENOMEM;
+ goto free_acl;
+ }
+
+ /* reduce number of entries by combining contiguous pages into single memory entry */
+ prev_page = mapping->pages[0];
+ parcel->mem_entries[0].phys_addr = cpu_to_le64(page_to_phys(prev_page));
+ entry_size = PAGE_SIZE;
+ for (i = 1, j = 0; i < mapping->npages; i++) {
+ curr_page = mapping->pages[i];
+ if (pages_are_mergeable(prev_page, curr_page)) {
+ entry_size += PAGE_SIZE;
+ } else {
+ parcel->mem_entries[j].size = cpu_to_le64(entry_size);
+ j++;
+ parcel->mem_entries[j].phys_addr =
+ cpu_to_le64(page_to_phys(curr_page));
+ entry_size = PAGE_SIZE;
+ }
+
+ prev_page = curr_page;
+ }
+ parcel->mem_entries[j].size = cpu_to_le64(entry_size);
+
+ list_add(&mapping->list, &ghvm->memory_mappings);
+ mutex_unlock(&ghvm->mm_lock);
+ return 0;
+free_acl:
+ kfree(parcel->acl_entries);
+unpin_pages:
+ unpin_user_pages(mapping->pages, pinned);
+free_pages:
+ kfree(mapping->pages);
+unlock_pages:
+ account_locked_vm(ghvm->mm, mapping->npages, false);
+free_mapping:
+ kfree(mapping);
+unlock:
+ mutex_unlock(&ghvm->mm_lock);
+ return ret;
+}
diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h
index 86b9cb60118dd..91d6dd26fcc89 100644
--- a/include/uapi/linux/gunyah.h
+++ b/include/uapi/linux/gunyah.h
@@ -20,4 +20,41 @@
*/
#define GH_CREATE_VM _IO(GH_IOCTL_TYPE, 0x0) /* Returns a Gunyah VM fd */
+/*
+ * ioctls for VM fds
+ */
+
+/**
+ * enum gh_mem_flags - Possible flags on &struct gh_userspace_memory_region
+ * @GH_MEM_ALLOW_READ: Allow guest to read the memory
+ * @GH_MEM_ALLOW_WRITE: Allow guest to write to the memory
+ * @GH_MEM_ALLOW_EXEC: Allow guest to execute instructions in the memory
+ */
+enum gh_mem_flags {
+ GH_MEM_ALLOW_READ = 1UL << 0,
+ GH_MEM_ALLOW_WRITE = 1UL << 1,
+ GH_MEM_ALLOW_EXEC = 1UL << 2,
+};
+
+/**
+ * struct gh_userspace_memory_region - Userspace memory descripion for GH_VM_SET_USER_MEM_REGION
+ * @label: Identifer to the region which is unique to the VM.
+ * @flags: Flags for memory parcel behavior. See &enum gh_mem_flags.
+ * @guest_phys_addr: Location of the memory region in guest's memory space (page-aligned)
+ * @memory_size: Size of the region (page-aligned)
+ * @userspace_addr: Location of the memory region in caller (userspace)'s memory
+ *
+ * See Documentation/virt/gunyah/vm-manager.rst for further details.
+ */
+struct gh_userspace_memory_region {
+ __u32 label;
+ __u32 flags;
+ __u64 guest_phys_addr;
+ __u64 memory_size;
+ __u64 userspace_addr;
+};
+
+#define GH_VM_SET_USER_MEM_REGION _IOW(GH_IOCTL_TYPE, 0x1, \
+ struct gh_userspace_memory_region)
+
#endif
