diff mbox series

[v8,14/28] gunyah: vm_mgr: Add/remove user memory regions

Message ID 20221219225850.2397345-15-quic_eberman@quicinc.com
State New
Headers show
Series Drivers for gunyah hypervisor | expand

Commit Message

Elliot Berman Dec. 19, 2022, 10:58 p.m. UTC
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@quicinc.com>
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 drivers/virt/gunyah/Makefile    |   2 +-
 drivers/virt/gunyah/vm_mgr.c    |  45 +++++++
 drivers/virt/gunyah/vm_mgr.h    |  27 ++++
 drivers/virt/gunyah/vm_mgr_mm.c | 221 ++++++++++++++++++++++++++++++++
 include/uapi/linux/gunyah.h     |  22 ++++
 5 files changed, 316 insertions(+), 1 deletion(-)
 create mode 100644 drivers/virt/gunyah/vm_mgr_mm.c

Comments

Srivatsa Vaddagiri Jan. 20, 2023, 5:34 a.m. UTC | #1
* Elliot Berman <quic_eberman@quicinc.com> [2022-12-19 14:58:35]:

>  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;
>  
> +	list_for_each_entry_safe(mapping, tmp, &ghvm->memory_mappings, list) {
> +		gh_vm_mem_mapping_reclaim(ghvm, mapping);

kfree(mapping) also?

> +	}
>  	put_gh_rm(ghvm->rm);
>  	kfree(ghvm);
>  	return 0;

[snip]

> +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;
> +	__u32 mem_size;

'gh_userspace_memory_region' allows 64-bit mem_size, so perhaps make it 64-bit
here as well?

> +struct gunyah_vm_memory_mapping *gh_vm_mem_mapping_alloc(struct gunyah_vm *ghvm,
> +							struct gh_userspace_memory_region *region)
> +{
> +	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;
> +
> +	if (!region->memory_size || !PAGE_ALIGNED(region->memory_size) ||
> +		!PAGE_ALIGNED(region->userspace_addr))
> +		return ERR_PTR(-EINVAL);
> +
> +	ret = mutex_lock_interruptible(&ghvm->mm_lock);
> +	if (ret)
> +		return ERR_PTR(ret);
> +	mapping = __gh_vm_mem_mapping_find(ghvm, region->label);
> +	if (mapping) {
> +		ret = -EEXIST;
> +		goto unlock;

We should avoid kfree(mapping) in this case?

> +	}
> +
> +	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;
> +		}
> +	}
> +
> +	list_add(&mapping->list, &ghvm->memory_mappings);

I think we need to either avoid adding to the list this early (until all steps
below are successfull) or maintain some additional state in 'mapping' to
indicate that its work in progress. Consider the race condition for example when
multiple threads call SET_USER_MEM_REGION ioctl on same label (one with size > 0
and other with size = 0), which can lead to unpleasant outcome AFAICS.

> +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;

Can you check this error path? We seem to call unpin_user_page() in this path,
which is not correct.

> +	}
> +
> +	pinned = pin_user_pages_fast(region->userspace_addr, mapping->npages,
> +					FOLL_WRITE | FOLL_LONGTERM, mapping->pages);
> +	if (pinned < 0) {
> +		ret = pinned;
> +		goto reclaim;

Same comment as above

> +	parcel->acl_entries[0].vmid = ghvm->vmid;

cpu_to_le() wrapper missing here and few other places in this function. Pls check.
diff mbox series

Patch

diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
index e817ae6deddc..9d6f900ab7b0 100644
--- a/drivers/virt/gunyah/Makefile
+++ b/drivers/virt/gunyah/Makefile
@@ -1,5 +1,5 @@ 
 obj-$(CONFIG_GUNYAH) += gunyah.o
 
 gunyah_rsc_mgr-y += rsc_mgr.o rsc_mgr_rpc.o
-gunyah_rsc_mgr-$(CONFIG_GUNYAH_VM_MANAGER) += vm_mgr.o
+gunyah_rsc_mgr-$(CONFIG_GUNYAH_VM_MANAGER) += vm_mgr.o vm_mgr_mm.o
 obj-$(CONFIG_GUNYAH_RESOURCE_MANAGER) += gunyah_rsc_mgr.o
diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c
index 9c796e5edcf1..a7220ad41669 100644
--- a/drivers/virt/gunyah/vm_mgr.c
+++ b/drivers/virt/gunyah/vm_mgr.c
@@ -33,14 +33,55 @@  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(&region, argp, sizeof(region)))
+			break;
+
+		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) {
+			r = 0;
+			mapping = gh_vm_mem_mapping_alloc(ghvm, &region);
+			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;
@@ -52,7 +93,11 @@  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;
 
+	list_for_each_entry_safe(mapping, tmp, &ghvm->memory_mappings, list) {
+		gh_vm_mem_mapping_reclaim(ghvm, 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 84e3d1a8571d..955856c1310b 100644
--- a/drivers/virt/gunyah/vm_mgr.h
+++ b/drivers/virt/gunyah/vm_mgr.h
@@ -7,6 +7,9 @@ 
 #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>
 
@@ -17,9 +20,33 @@  static inline long gh_dev_vm_mgr_ioctl(struct gh_rm_rpc *rm, unsigned int cmd, u
 	{ return -ENOIOCTLCMD; }
 #endif
 
+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;
+	__u32 mem_size;
+	struct page **pages;
+	unsigned long npages;
+};
+
 struct gunyah_vm {
 	u16 vmid;
 	struct gh_rm_rpc *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..800d35da14ba
--- /dev/null
+++ b/drivers/virt/gunyah/vm_mgr_mm.c
@@ -0,0 +1,221 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022 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;
+
+
+	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;
+}
+
+struct gunyah_vm_memory_mapping *gh_vm_mem_mapping_alloc(struct gunyah_vm *ghvm,
+							struct gh_userspace_memory_region *region)
+{
+	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;
+
+	if (!region->memory_size || !PAGE_ALIGNED(region->memory_size) ||
+		!PAGE_ALIGNED(region->userspace_addr))
+		return ERR_PTR(-EINVAL);
+
+	ret = mutex_lock_interruptible(&ghvm->mm_lock);
+	if (ret)
+		return ERR_PTR(ret);
+	mapping = __gh_vm_mem_mapping_find(ghvm, region->label);
+	if (mapping) {
+		ret = -EEXIST;
+		goto unlock;
+	}
+
+	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;
+		}
+	}
+
+	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 = 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, &parcel->acl_entries[1].vmid);
+		if (ret)
+			goto reclaim;
+		/* 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 = mem_entries[0].ipa_base = page_to_phys(mapping->pages[0]);
+	mem_entries[0].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)) {
+			mem_entries[j].size += PAGE_SIZE;
+		} else {
+			j++;
+			mem_entries[j].ipa_base = curr_page;
+			mem_entries[j].size = PAGE_SIZE;
+		}
+
+		prev_page = curr_page;
+	}
+
+	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;
+	}
+
+	switch (mapping->share_type) {
+	case VM_MEM_LEND:
+		ret = gh_rm_mem_lend(ghvm->rm, parcel);
+		break;
+	case VM_MEM_SHARE:
+		ret = gh_rm_mem_share(ghvm->rm, parcel);
+		break;
+	}
+	if (ret > 0)
+		ret = -EINVAL;
+	if (ret)
+		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 {
+	__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