Re: [PATCH v10 12/26] gunyah: vm_mgr: Add/remove user memory regions
From: Alex Elder
Date: Thu Feb 23 2023 - 19:34:37 EST
On 2/14/23 3:24 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>
---
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)
Would there be any value in allowing a zero-size memory
region to be created? Maybe that doesn't make sense, but
I guess i'm questioning whether a zero memory region size
have special meaning in this interface is a good thing to
do. You could sensibly have a separate REMOVE_USER_MEM_REGION
request, and still permit 0 to be a valid size.
+ r = gh_vm_mem_alloc(ghvm, ®ion);
+ else
+ r = gh_vm_mem_free(ghvm, region.label);
+ 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,
Are there any other share types anticipated? Even if
there were, for now you could use a Boolean to distinguish
between shared or lent (at least until a third option
materializes).
+};
+
+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)
Is there not some existing function that captures this?
In any case, it's used in one place and I think it would
be clearer to just put the logic there rather than hiding
it behind this function.
+{
+ 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;
+}
+
. . .
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.
Maybe this is described somewhere, but what is the purpose
of the label? Who uses it? Is it meant to be a value
only the current owner of a resource understands? Or does
resource manager use it internally, or what?
+ * @flags: Flags for memory parcel behavior
+ * @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;
Define the possible permission values separate from
the structure.
-Alex
+#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