On 20/01/2023 22:46, 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>
---
drivers/virt/gunyah/Makefile | 2 +-
drivers/virt/gunyah/vm_mgr.c | 46 +++++++
drivers/virt/gunyah/vm_mgr.h | 28 +++-
drivers/virt/gunyah/vm_mgr_mm.c | 223 ++++++++++++++++++++++++++++++++
include/uapi/linux/gunyah.h | 22 ++++
5 files changed, 319 insertions(+), 2 deletions(-)
create mode 100644 drivers/virt/gunyah/vm_mgr_mm.c
diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
index 03951cf82023..ff8bc4925392 100644
--- a/drivers/virt/gunyah/Makefile
+++ b/drivers/virt/gunyah/Makefile
@@ -2,5 +2,5 @@
obj-$(CONFIG_GUNYAH) += gunyah.o
-gunyah_rsc_mgr-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o
+gunyah_rsc_mgr-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o vm_mgr_mm.o
obj-$(CONFIG_GUNYAH) += gunyah_rsc_mgr.o
diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c
index 0864dbd77e28..b847fde63333 100644
--- a/drivers/virt/gunyah/vm_mgr.c
+++ b/drivers/virt/gunyah/vm_mgr.c
@@ -35,14 +35,55 @@ static __must_check struct gunyah_vm *gunyah_vm_alloc(struct gh_rm_rpc *rm)
ghvm->vmid = vmid;
ghvm->rm = rm;
+ mutex_init(&ghvm->mm_lock);
+ INIT_LIST_HEAD(&ghvm->memory_mappings);
+
return ghvm;
}
static long gh_vm_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
+ struct gunyah_vm *ghvm = filp->private_data;
+ void __user *argp = (void __user *)arg;
long r;
switch (cmd) {
+ case GH_VM_SET_USER_MEM_REGION: {
+ struct gunyah_vm_memory_mapping *mapping;
+ struct gh_userspace_memory_region region;
+
+ r = -EFAULT;
+ if (copy_from_user(®ion, argp, sizeof(region)))
+ break;
Why not be explict about the error codes, do something like.
if (copy_from_user(®ion, argp, sizeof(region)))
return -EFAULT;
setting r value everytime before starting any code is making the code
more reader unfriendly.
+
+ r = -EINVAL;
+ /* All other flag bits are reserved for future use */
+ if (region.flags & ~(GH_MEM_ALLOW_READ | GH_MEM_ALLOW_WRITE | GH_MEM_ALLOW_EXEC |
+ GH_MEM_LENT))
+ break;
+
+
+ if (region.memory_size) {
This behaviour allocating memory in presense of valid memory_size and
finding memory in cases of zero size needs to be described properly in
the uapi so that the users are aware of this.
+ r = 0;
+ mapping = gh_vm_mem_mapping_alloc(ghvm, ®ion);
+ if (IS_ERR(mapping)) {
+ r = PTR_ERR(mapping);
+ break;
+ }
+ } else {
+ mapping = gh_vm_mem_mapping_find(ghvm, region.label);
+ if (IS_ERR(mapping)) {
+ r = PTR_ERR(mapping);
+ break;
+ }
+ r = 0;
+ if (!mapping)
+ break;
+ gh_vm_mem_mapping_reclaim(ghvm, mapping);
+ kfree(mapping);
+ }
+ break;
+ }
default:
r = -ENOTTY;
break;
@@ -54,7 +95,12 @@ static long gh_vm_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
static int gh_vm_release(struct inode *inode, struct file *filp)
{
struct gunyah_vm *ghvm = filp->private_data;
+ struct gunyah_vm_memory_mapping *mapping, *tmp;
Locking?
+ list_for_each_entry_safe(mapping, tmp, &ghvm->memory_mappings, list) {
+ gh_vm_mem_mapping_reclaim(ghvm, mapping);
+ kfree(mapping);
+ }
put_gh_rm(ghvm->rm);
kfree(ghvm);
return 0;
diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h
index e47f34de7f9e..6b38bf780f76 100644
--- a/drivers/virt/gunyah/vm_mgr.h
+++ b/drivers/virt/gunyah/vm_mgr.h
@@ -7,14 +7,40 @@
#define _GH_PRIV_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 gunyah_vm_mem_share_type {
+ VM_MEM_SHARE,
+ VM_MEM_LEND,
+};
+
+struct gunyah_vm_memory_mapping {
+ struct list_head list;
+ enum gunyah_vm_mem_share_type share_type;
+ struct gh_rm_mem_parcel parcel;
+
+ __u64 guest_phys_addr;
+ struct page **pages;
+ unsigned long npages;
+};
+
struct gunyah_vm {
u16 vmid;
- struct gh_rm_rpc *rm;
+ struct gh_rm *rm;
+
+ struct mutex mm_lock;
+ struct list_head memory_mappings;
};
+struct gunyah_vm_memory_mapping *gh_vm_mem_mapping_alloc(struct gunyah_vm *ghvm,
+ struct gh_userspace_memory_region *region);
+void gh_vm_mem_mapping_reclaim(struct gunyah_vm *ghvm, struct gunyah_vm_memory_mapping *mapping);
+struct gunyah_vm_memory_mapping *gh_vm_mem_mapping_find(struct gunyah_vm *ghvm, u32 label);
+
#endif
diff --git a/drivers/virt/gunyah/vm_mgr_mm.c b/drivers/virt/gunyah/vm_mgr_mm.c
new file mode 100644
index 000000000000..f2dbdb4ee8ab
--- /dev/null
+++ b/drivers/virt/gunyah/vm_mgr_mm.c
@@ -0,0 +1,223 @@
+// 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 inline bool page_contiguous(phys_addr_t p, phys_addr_t t)
+{
+ return t - p == PAGE_SIZE;
+}
+
+static struct gunyah_vm_memory_mapping *__gh_vm_mem_mapping_find(struct gunyah_vm *ghvm, u32 label)
+{
+ struct gunyah_vm_memory_mapping *mapping;
+
+
only one line.
+ list_for_each_entry(mapping, &ghvm->memory_mappings, list)
+ if (mapping->parcel.label == label)
+ return mapping;
+
+ return NULL;
+}
+
+void gh_vm_mem_mapping_reclaim(struct gunyah_vm *ghvm, struct gunyah_vm_memory_mapping *mapping)
+{
+ int i, 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)
+ for (i = 0; i < mapping->npages; i++)
+ unpin_user_page(mapping->pages[i]);
+
+ kfree(mapping->pages);
+ kfree(mapping->parcel.acl_entries);
+ kfree(mapping->parcel.mem_entries);
+
+ mutex_lock(&ghvm->mm_lock);
+ list_del(&mapping->list);
+ mutex_unlock(&ghvm->mm_lock);
+}
+
+struct gunyah_vm_memory_mapping *gh_vm_mem_mapping_find(struct gunyah_vm *ghvm, u32 label)
+{
+ struct gunyah_vm_memory_mapping *mapping;
+ int ret;
+
+ ret = mutex_lock_interruptible(&ghvm->mm_lock);
+ if (ret)
+ return ERR_PTR(ret);
+ mapping = __gh_vm_mem_mapping_find(ghvm, label);
+ mutex_unlock(&ghvm->mm_lock);
+ return mapping ? : ERR_PTR(-ENODEV);
+}
+
+struct gunyah_vm_memory_mapping *gh_vm_mem_mapping_alloc(struct gunyah_vm *ghvm,
+ struct gh_userspace_memory_region *region)
+{
Is this a static functoin or an exported symbol?
+ phys_addr_t curr_page, prev_page;
+ struct gunyah_vm_memory_mapping *mapping, *tmp_mapping;
+ struct gh_rm_mem_entry *mem_entries;
+ int i, j, pinned, ret = 0;
+ struct gh_rm_mem_parcel *parcel;
+ size_t entry_size;
+ u16 vmid; > +
Reverse christmas tree to sor local variables would be nice.
+ if (!region->memory_size || !PAGE_ALIGNED(region->memory_size) ||
+ !PAGE_ALIGNED(region->userspace_addr))
Even this alignment needs some documentation.
Or why not just let the user only pass number of pages instead of size?
+ return ERR_PTR(-EINVAL);
+
+ if (!gh_api_has_feature(GH_API_FEATURE_MEMEXTENT))
+ return ERR_PTR(-EOPNOTSUPP);
We should proabably move this as very first check while handling this IOCTL.
+
+ ret = mutex_lock_interruptible(&ghvm->mm_lock);
+ if (ret)
+ return ERR_PTR(ret);
+ mapping = __gh_vm_mem_mapping_find(ghvm, region->label);
so label is unique and userspace proabably aware of this?
Can we have more than one userspace doing this? and if so how can it
ensure that each label is unique?
+ if (mapping) {
+ mutex_unlock(&ghvm->mm_lock);
+ return ERR_PTR(-EEXIST);
+ }
+
+ mapping = kzalloc(sizeof(*mapping), GFP_KERNEL);
+ if (!mapping) {
+ ret = -ENOMEM;
+ goto unlock;
+ }
+
+ mapping->parcel.label = region->label;
+ mapping->guest_phys_addr = region->guest_phys_addr;
+ mapping->npages = region->memory_size >> PAGE_SHIFT;
+ parcel = &mapping->parcel;
+ parcel->mem_handle = GH_MEM_HANDLE_INVAL; /* to be filled later by mem_share/mem_lend */
+ parcel->mem_type = GH_RM_MEM_TYPE_NORMAL;
+
+ /* Check for overlap */
+ list_for_each_entry(tmp_mapping, &ghvm->memory_mappings, list) {
+ if (!((mapping->guest_phys_addr + (mapping->npages << PAGE_SHIFT) <=
+ tmp_mapping->guest_phys_addr) ||
+ (mapping->guest_phys_addr >=
+ tmp_mapping->guest_phys_addr + (tmp_mapping->npages << PAGE_SHIFT)))) {
+ ret = -EEXIST;
+ goto unlock;
+ }
+ }
This looks like we will loop every mappign for each allocation giving us
an O(n), How frequent and how many max mappings can be there in the system?
+
+ list_add(&mapping->list, &ghvm->memory_mappings);
+unlock:
+ mutex_unlock(&ghvm->mm_lock);
+ if (ret)
+ goto free_mapping;
+
+ mapping->pages = kcalloc(mapping->npages, sizeof(*mapping->pages), GFP_KERNEL);
+ if (!mapping->pages) {
+ ret = -ENOMEM;
+ goto reclaim;
+ }
+
+ pinned = pin_user_pages_fast(region->userspace_addr, mapping->npages,
+ FOLL_WRITE | FOLL_LONGTERM, mapping->pages);
+ if (pinned < 0) {
+ ret = pinned;
+ goto reclaim;
+ } else if (pinned != mapping->npages) {
+ ret = -EFAULT;
+ mapping->npages = pinned; /* update npages for reclaim */
+ goto reclaim;
+ }
+
+ if (region->flags & GH_MEM_LENT) {
+ parcel->n_acl_entries = 1;
+ mapping->share_type = VM_MEM_LEND;
+ } else {
+ 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 reclaim;
+ }
+
+ parcel->acl_entries[0].vmid = cpu_to_le16(ghvm->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;
+
+ if (mapping->share_type == VM_MEM_SHARE) {
+ ret = gh_rm_get_vmid(ghvm->rm, &vmid);
+ if (ret) {
+ if (ret > 0) {
+ pr_warn("RM failed to get this VM's VMID: %d", ret);
+ ret = -EINVAL;
+ }
+ goto reclaim;
+ }
+
+ 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;
+ }
+
+ mem_entries = kcalloc(mapping->npages, sizeof(*mem_entries), GFP_KERNEL);
+ if (!mem_entries) {
+ ret = -ENOMEM;
+ goto reclaim;
+ }
+
+ /* reduce number of entries by combining contiguous pages into single memory entry */
+ prev_page = page_to_phys(mapping->pages[0]);
+ mem_entries[0].ipa_base = cpu_to_le64(prev_page);
+ entry_size = PAGE_SIZE;
+ for (i = 1, j = 0; i < mapping->npages; i++) {
+ curr_page = page_to_phys(mapping->pages[i]);
+ if (page_contiguous(prev_page, curr_page)) {
+ entry_size += PAGE_SIZE;
+ } else {
+ mem_entries[j].size = cpu_to_le64(entry_size);
+ j++;
+ mem_entries[j].ipa_base = cpu_to_le64(curr_page);
+ entry_size = PAGE_SIZE;
+ }
+
+ prev_page = curr_page;
+ }
+ mem_entries[j].size = cpu_to_le64(entry_size);
+
+ parcel->n_mem_entries = j + 1;
+ parcel->mem_entries = kmemdup(mem_entries, sizeof(*mem_entries) * parcel->n_mem_entries,
+ GFP_KERNEL);
+ kfree(mem_entries);
+ if (!parcel->mem_entries) {
+ ret = -ENOMEM;
+ goto reclaim;
+ }
+
+ return mapping;
+reclaim:
+ gh_vm_mem_mapping_reclaim(ghvm, mapping);
+free_mapping:
+ kfree(mapping);
+ return ERR_PTR(ret);
+}
diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h
index 88a40d6e0b96..574f33b198d0 100644
--- a/include/uapi/linux/gunyah.h
+++ b/include/uapi/linux/gunyah.h
@@ -20,4 +20,26 @@
*/
#define GH_CREATE_VM _IO(GH_IOCTL_TYPE, 0x0) /* Returns a Gunyah VM fd */
+/*
+ * ioctls for VM fds
+ */
+struct gh_userspace_memory_region {
This struct needs some kernedoc.
+ __u32 label;
+#define GH_MEM_ALLOW_READ (1UL << 0)
+#define GH_MEM_ALLOW_WRITE (1UL << 1)
+#define GH_MEM_ALLOW_EXEC (1UL << 2)
+/*
+ * The guest will be lent the memory instead of shared.
+ * In other words, the guest has exclusive access to the memory region and the host loses access.
+ */
+#define GH_MEM_LENT (1UL << 3)
+ __u32 flags;
+ __u64 guest_phys_addr;
+ __u64 memory_size;
if we are only expecting pages, this should probably be make explict by
using nr_pages instead of size
+ __u64 userspace_addr;
+};
+
+#define GH_VM_SET_USER_MEM_REGION _IOW(GH_IOCTL_TYPE, 0x1, \
+ struct gh_userspace_memory_region)
+
#endif
