Re: [PATCH v10 12/26] gunyah: vm_mgr: Add/remove user memory regions
From: Srinivas Kandagatla
Date: Tue Feb 21 2023 - 07:29:27 EST
On 14/02/2023 21:24, 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 | 44 ++++++
drivers/virt/gunyah/vm_mgr.h | 25 ++++
drivers/virt/gunyah/vm_mgr_mm.c | 235 ++++++++++++++++++++++++++++++++
include/uapi/linux/gunyah.h | 33 +++++
5 files changed, 338 insertions(+), 1 deletion(-)
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 fd890a57172e..84102bac03cc 100644
--- a/drivers/virt/gunyah/vm_mgr.c
+++ b/drivers/virt/gunyah/vm_mgr.c
@@ -18,8 +18,16 @@
static void gh_vm_free(struct work_struct *work)
{
struct gh_vm *ghvm = container_of(work, struct gh_vm, free_work);
+ struct gh_vm_mem *mapping, *tmp;
int ret;
+ mutex_lock(&ghvm->mm_lock);
+ list_for_each_entry_safe(mapping, tmp, &ghvm->memory_mappings, list) {
+ gh_vm_mem_reclaim(ghvm, mapping);
+ kfree(mapping);
+ }
+ mutex_unlock(&ghvm->mm_lock);
+
ret = gh_rm_dealloc_vmid(ghvm->rm, ghvm->vmid);
if (ret)
pr_warn("Failed to deallocate vmid: %d\n", ret);
@@ -48,11 +56,46 @@ static __must_check struct gh_vm *gh_vm_alloc(struct gh_rm *rm)
ghvm->vmid = vmid;
ghvm->rm = rm;
+ mutex_init(&ghvm->mm_lock);
+ INIT_LIST_HEAD(&ghvm->memory_mappings);
INIT_WORK(&ghvm->free_work, gh_vm_free);
return ghvm;
}
+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;
+
+ switch (cmd) {
+ case GH_VM_SET_USER_MEM_REGION: {
+ struct gh_userspace_memory_region region;
+
+ 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 |
+ GH_MEM_LENT))
+ return -EINVAL;
+
+
+ if (region.memory_size)
+ r = gh_vm_mem_alloc(ghvm, ®ion);
+ else
+ r = gh_vm_mem_free(ghvm, region.label);
Looks like we are repurposing GH_VM_SET_USER_MEM_REGION for allocation
and freeing.
Should we have corresponding GH_VM_UN_SET_USER_MEM_REGION instead for
freeing? given that label is the only relevant member of struct
gh_userspace_memory_region in free case.
+ break;
+ }
+ default:
+ r = -ENOTTY;
+ break;
+ }
+
+ return r;
+}
+
static int gh_vm_release(struct inode *inode, struct file *filp)
{
struct gh_vm *ghvm = filp->private_data;
@@ -65,6 +108,7 @@ static int gh_vm_release(struct inode *inode, struct file *filp)
}
static const struct file_operations gh_vm_fops = {
+ .unlocked_ioctl = gh_vm_ioctl,
.release = gh_vm_release,
.compat_ioctl = compat_ptr_ioctl,
.llseek = noop_llseek,
diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h
index 76954da706e9..97bc00c34878 100644
--- a/drivers/virt/gunyah/vm_mgr.h
+++ b/drivers/virt/gunyah/vm_mgr.h
@@ -7,16 +7,41 @@
#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 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 {
u16 vmid;
struct gh_rm *rm;
struct work_struct free_work;
+ 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, struct gh_vm_mem *mapping);
+int gh_vm_mem_free(struct gh_vm *ghvm, u32 label);
+struct gh_vm_mem *gh_vm_mem_find(struct gh_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..03e71a36ea3b
--- /dev/null
+++ b/drivers/virt/gunyah/vm_mgr_mm.c
@@ -0,0 +1,235 @@
+// 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 gh_vm_mem *__gh_vm_mem_find(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;
+}
+
+void gh_vm_mem_reclaim(struct gh_vm *ghvm, struct gh_vm_mem *mapping)
+ __must_hold(&ghvm->mm_lock)
+{
+ 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);
what the behavoir of hypervisor if we failed to reclaim the pages?
+ }
+
+ if (!ret)
So we will leave the user pages pinned if hypervisor call fails, but
further down we free the mapping all together.
Am not 100% sure if this will have any side-effect, but is it okay to
leave user-pages pinned with no possiblity of unpinning them in such cases?
+ 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);
+
+ list_del(&mapping->list);
+}
+
+struct gh_vm_mem *gh_vm_mem_find(struct gh_vm *ghvm, u32 label)
+{
+ struct gh_vm_mem *mapping;
+ int ret;
+
+ ret = mutex_lock_interruptible(&ghvm->mm_lock);
+ if (ret)
+ return ERR_PTR(ret);
new line would be nice here.
+ mapping = __gh_vm_mem_find(ghvm, label);
+ mutex_unlock(&ghvm->mm_lock);
new line would be nice here.
+ return mapping ? : ERR_PTR(-ENODEV);
+}
+
+int gh_vm_mem_alloc(struct gh_vm *ghvm, struct gh_userspace_memory_region *region)
+{
+ struct gh_vm_mem *mapping, *tmp_mapping;
+ struct gh_rm_mem_entry *mem_entries;
+ phys_addr_t curr_page, prev_page;
+ struct gh_rm_mem_parcel *parcel;
+ int i, j, pinned, ret = 0;
+ size_t entry_size;
+ u16 vmid;
+
+ if (!gh_api_has_feature(GH_API_FEATURE_MEMEXTENT))
+ return -EOPNOTSUPP;
Should this not be first thing to do in ioctl before even entering this
function?
+
+ if (!region->memory_size || !PAGE_ALIGNED(region->memory_size) ||
+ !PAGE_ALIGNED(region->userspace_addr) || !PAGE_ALIGNED(region->guest_phys_addr))
+ return -EINVAL;
+
+ ret = mutex_lock_interruptible(&ghvm->mm_lock);
+ if (ret)
+ return ret;
new line.
+ mapping = __gh_vm_mem_find(ghvm, region->label);
+ if (mapping) {
+ mutex_unlock(&ghvm->mm_lock);
+ return -EEXIST;
+ }
+
+ mapping = kzalloc(sizeof(*mapping), GFP_KERNEL);
+ if (!mapping) {
+ ret = -ENOMEM;
+ goto free_mapping;
how about,
mutex_unlock(&ghvm->mm_lock);
return -ENMEM;
+ }
+
+ 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 free_mapping;
+ }
+ }
+
+ list_add(&mapping->list, &ghvm->memory_mappings);
+
+ mapping->pages = kcalloc(mapping->npages, sizeof(*mapping->pages), GFP_KERNEL);
+ if (!mapping->pages) {
+ ret = -ENOMEM;
+ mapping->npages = 0; /* update npages for reclaim */
+ goto reclaim;
+ }
+
+ pinned = pin_user_pages_fast(region->userspace_addr, mapping->npages,
+ FOLL_WRITE | FOLL_LONGTERM, mapping->pages);
+ if (pinned < 0) {
+ ret = pinned;
+ mapping->npages = 0; /* update npages for reclaim */
+ 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);
new line
+ 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)
+ 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;
new line
+ 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;
+ }
+
+ mutex_unlock(&ghvm->mm_lock);
+ return 0;
+reclaim:
+ gh_vm_mem_reclaim(ghvm, mapping);
+free_mapping:
+ kfree(mapping);
+ mutex_unlock(&ghvm->mm_lock);
+ return ret;
+}
+
+int gh_vm_mem_free(struct gh_vm *ghvm, u32 label)
+{
+ struct gh_vm_mem *mapping;
+ int ret;
+
+ ret = mutex_lock_interruptible(&ghvm->mm_lock);
+ if (ret)
+ return ret;
+
+ mapping = __gh_vm_mem_find(ghvm, label);
+ if (!mapping)
+ goto out;
+
+ gh_vm_mem_reclaim(ghvm, mapping);
+ kfree(mapping);
+out:
+ mutex_unlock(&ghvm->mm_lock);
+ return ret;
+}
diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h
index 10ba32d2b0a6..d85d12119a48 100644
--- a/include/uapi/linux/gunyah.h
+++ b/include/uapi/linux/gunyah.h
@@ -20,4 +20,37 @@
*/
#define GH_CREATE_VM _IO(GH_IOCTL_TYPE, 0x0) /* Returns a Gunyah VM fd */
+/*
+ * ioctls for VM fds
+ */
+
+/**
+ * struct gh_userspace_memory_region - Userspace memory descripion for GH_VM_SET_USER_MEM_REGION
+ * @label: Unique identifer to the region.
+ * @flags: Flags for memory parcel behavior
+ * @guest_phys_addr: Location of the memory region in guest's memory space (page-aligned)#
Note about overlapping here would be useful.
+ * @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;
+#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;
+ __u64 userspace_addr;
+};
+
+#define GH_VM_SET_USER_MEM_REGION _IOW(GH_IOCTL_TYPE, 0x1, \
+ struct gh_userspace_memory_region)
+
#endif