[PATCH v10 19/21] virt: geniezone: Provide individual VM memory statistics within debugfs

From: Yi-De Wu
Date: Fri Apr 12 2024 - 03:03:42 EST

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From: "Jerry Wang" <ze-yu.wang@xxxxxxxxxxxx>

Created a dedicated per-VM debugfs folder under gzvm, providing
user-level programs with easy access to per-VM memory statistics for
debugging and profiling purposes. This enables users to effectively
analyze and optimize the memory usage of individual virtual machines.

Two types of information can be obtained:

`cat /sys/kernel/debug/gzvm/<pid>-<vmid>/protected_hyp_mem` shows memory
used by the hypervisor and the size of the stage 2 table in bytes.

`cat /sys/kernel/debug/gzvm/<pid>-<vmid>/protected_shared_mem` gives
memory used by the shared resources of the guest and host in bytes.

For example:
console:/ # cat /sys/kernel/debug/gzvm/3417-15/protected_hyp_mem
180328
console:/ # cat /sys/kernel/debug/gzvm/3417-15/protected_shared_mem
262144
console:/ #

More stats will be added in the future.

Signed-off-by: Jerry Wang <ze-yu.wang@xxxxxxxxxxxx>
Signed-off-by: Liju-Clr Chen <liju-clr.chen@xxxxxxxxxxxx>
Signed-off-by: Yi-De Wu <yi-de.wu@xxxxxxxxxxxx>
---
arch/arm64/geniezone/gzvm_arch_common.h | 2 +
arch/arm64/geniezone/vm.c | 13 +++
drivers/virt/geniezone/gzvm_main.c | 6 ++
drivers/virt/geniezone/gzvm_vm.c | 137 ++++++++++++++++++++++++
include/linux/soc/mediatek/gzvm_drv.h | 17 +++
5 files changed, 175 insertions(+)

diff --git a/arch/arm64/geniezone/gzvm_arch_common.h b/arch/arm64/geniezone/gzvm_arch_common.h
index 8a082ba808a4..192d023722e5 100644
--- a/arch/arm64/geniezone/gzvm_arch_common.h
+++ b/arch/arm64/geniezone/gzvm_arch_common.h
@@ -26,6 +26,7 @@ enum {
GZVM_FUNC_SET_DTB_CONFIG = 16,
GZVM_FUNC_MAP_GUEST = 17,
GZVM_FUNC_MAP_GUEST_BLOCK = 18,
+ GZVM_FUNC_GET_STATISTICS = 19,
NR_GZVM_FUNC,
};

@@ -52,6 +53,7 @@ enum {
#define MT_HVC_GZVM_SET_DTB_CONFIG GZVM_HCALL_ID(GZVM_FUNC_SET_DTB_CONFIG)
#define MT_HVC_GZVM_MAP_GUEST GZVM_HCALL_ID(GZVM_FUNC_MAP_GUEST)
#define MT_HVC_GZVM_MAP_GUEST_BLOCK GZVM_HCALL_ID(GZVM_FUNC_MAP_GUEST_BLOCK)
+#define MT_HVC_GZVM_GET_STATISTICS GZVM_HCALL_ID(GZVM_FUNC_GET_STATISTICS)

#define GIC_V3_NR_LRS 16

diff --git a/arch/arm64/geniezone/vm.c b/arch/arm64/geniezone/vm.c
index eb28c3850b5d..a477546c5a1a 100644
--- a/arch/arm64/geniezone/vm.c
+++ b/arch/arm64/geniezone/vm.c
@@ -431,3 +431,16 @@ int gzvm_arch_map_guest_block(u16 vm_id, int memslot_id, u64 gfn, u64 nr_pages)
return gzvm_hypcall_wrapper(MT_HVC_GZVM_MAP_GUEST_BLOCK, vm_id,
memslot_id, gfn, nr_pages, 0, 0, 0, &res);
}
+
+int gzvm_arch_get_statistics(struct gzvm *gzvm)
+{
+ struct arm_smccc_res res;
+ int ret;
+
+ ret = gzvm_hypcall_wrapper(MT_HVC_GZVM_GET_STATISTICS, gzvm->vm_id,
+ 0, 0, 0, 0, 0, 0, &res);
+
+ gzvm->stat.protected_hyp_mem = ((ret == 0) ? res.a1 : 0);
+ gzvm->stat.protected_shared_mem = ((ret == 0) ? res.a2 : 0);
+ return ret;
+}
diff --git a/drivers/virt/geniezone/gzvm_main.c b/drivers/virt/geniezone/gzvm_main.c
index 8f11a27f2723..d17505cf9755 100644
--- a/drivers/virt/geniezone/gzvm_main.c
+++ b/drivers/virt/geniezone/gzvm_main.c
@@ -109,6 +109,11 @@ static int gzvm_drv_probe(struct platform_device *pdev)
ret = gzvm_drv_irqfd_init();
if (ret)
return ret;
+
+ ret = gzvm_drv_debug_init();
+ if (ret)
+ return ret;
+
return 0;
}

@@ -117,6 +122,7 @@ static int gzvm_drv_remove(struct platform_device *pdev)
gzvm_drv_irqfd_exit();
gzvm_destroy_all_vms();
misc_deregister(&gzvm_dev);
+ gzvm_drv_debug_exit();
return 0;
}

diff --git a/drivers/virt/geniezone/gzvm_vm.c b/drivers/virt/geniezone/gzvm_vm.c
index 04af59b77189..e5751b07e425 100644
--- a/drivers/virt/geniezone/gzvm_vm.c
+++ b/drivers/virt/geniezone/gzvm_vm.c
@@ -11,11 +11,14 @@
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/soc/mediatek/gzvm_drv.h>
+#include <linux/debugfs.h>
#include "gzvm_common.h"

static DEFINE_MUTEX(gzvm_list_lock);
static LIST_HEAD(gzvm_list);

+static struct dentry *gzvm_debugfs_dir;
+
int gzvm_gfn_to_hva_memslot(struct gzvm_memslot *memslot, u64 gfn,
u64 *hva_memslot)
{
@@ -315,6 +318,12 @@ static void gzvm_destroy_all_ppage(struct gzvm *gzvm)
}
}

+static int gzvm_destroy_vm_debugfs(struct gzvm *vm)
+{
+ debugfs_remove_recursive(vm->debug_dir);
+ return 0;
+}
+
static void gzvm_destroy_vm(struct gzvm *gzvm)
{
size_t allocated_size;
@@ -341,6 +350,8 @@ static void gzvm_destroy_vm(struct gzvm *gzvm)
/* No need to lock here becauese it's single-threaded execution */
gzvm_destroy_all_ppage(gzvm);

+ gzvm_destroy_vm_debugfs(gzvm);
+
kfree(gzvm);
}

@@ -398,6 +409,113 @@ static void setup_vm_demand_paging(struct gzvm *vm)
}
}

+static int debugfs_open(struct inode *inode, struct file *file)
+{
+ file->private_data = inode->i_private;
+ return 0;
+}
+
+/**
+ * hyp_mem_read() - Get size of hypervisor-allocated memory and stage 2 table
+ * @file: Pointer to struct file
+ * @buf: User space buffer for storing the return value
+ * @len: Size of @buf, in bytes
+ * @offset: Pointer to loff_t
+ *
+ * Return: Size of hypervisor-allocated memory and stage 2 table, in bytes
+ */
+static ssize_t hyp_mem_read(struct file *file, char __user *buf, size_t len,
+ loff_t *offset)
+{
+ char tmp_buffer[GZVM_MAX_DEBUGFS_VALUE_SIZE] = {0};
+ struct gzvm *vm = file->private_data;
+ int ret;
+
+ if (*offset == 0) {
+ ret = gzvm_arch_get_statistics(vm);
+ if (ret)
+ return ret;
+ snprintf(tmp_buffer, sizeof(tmp_buffer), "%llu\n",
+ vm->stat.protected_hyp_mem);
+ if (copy_to_user(buf, tmp_buffer, sizeof(tmp_buffer)))
+ return -EFAULT;
+ *offset += sizeof(tmp_buffer);
+ return sizeof(tmp_buffer);
+ }
+ return 0;
+}
+
+/**
+ * shared_mem_read() - Get size of memory shared between host and guest
+ * @file: Pointer to struct file
+ * @buf: User space buffer for storing the return value
+ * @len: Size of @buf, in bytes
+ * @offset: Pointer to loff_t
+ *
+ * Return: Size of memory shared between host and guest, in bytes
+ */
+static ssize_t shared_mem_read(struct file *file, char __user *buf, size_t len,
+ loff_t *offset)
+{
+ char tmp_buffer[GZVM_MAX_DEBUGFS_VALUE_SIZE] = {0};
+ struct gzvm *vm = file->private_data;
+ int ret;
+
+ if (*offset == 0) {
+ ret = gzvm_arch_get_statistics(vm);
+ if (ret)
+ return ret;
+ snprintf(tmp_buffer, sizeof(tmp_buffer), "%llu\n",
+ vm->stat.protected_shared_mem);
+ if (copy_to_user(buf, tmp_buffer, sizeof(tmp_buffer)))
+ return -EFAULT;
+ *offset += sizeof(tmp_buffer);
+ return sizeof(tmp_buffer);
+ }
+ return 0;
+}
+
+static const struct file_operations hyp_mem_fops = {
+ .owner = THIS_MODULE,
+ .open = debugfs_open,
+ .read = hyp_mem_read,
+ .llseek = no_llseek,
+};
+
+static const struct file_operations shared_mem_fops = {
+ .owner = THIS_MODULE,
+ .open = debugfs_open,
+ .read = shared_mem_read,
+ .llseek = no_llseek,
+};
+
+static int gzvm_create_vm_debugfs(struct gzvm *vm)
+{
+ struct dentry *dent;
+ char dir_name[GZVM_MAX_DEBUGFS_DIR_NAME_SIZE];
+
+ if (vm->debug_dir) {
+ pr_warn("VM debugfs directory is duplicated\n");
+ return 0;
+ }
+
+ snprintf(dir_name, sizeof(dir_name), "%d-%d", task_pid_nr(current), vm->vm_id);
+
+ dent = debugfs_lookup(dir_name, gzvm_debugfs_dir);
+ if (dent) {
+ pr_warn("Debugfs directory is duplicated\n");
+ dput(dent);
+ return 0;
+ }
+ dent = debugfs_create_dir(dir_name, gzvm_debugfs_dir);
+ vm->debug_dir = dent;
+
+ debugfs_create_file("protected_shared_mem", 0444, dent, vm, &shared_mem_fops);
+ debugfs_create_file("protected_hyp_mem", 0444, dent, vm, &hyp_mem_fops);
+
+ return 0;
+}
+
static int setup_mem_alloc_mode(struct gzvm *vm)
{
int ret;
@@ -457,6 +575,8 @@ static struct gzvm *gzvm_create_vm(unsigned long vm_type)
list_add(&gzvm->vm_list, &gzvm_list);
mutex_unlock(&gzvm_list_lock);

+ gzvm_create_vm_debugfs(gzvm);
+
pr_debug("VM-%u is created\n", gzvm->vm_id);

return gzvm;
@@ -494,3 +614,20 @@ void gzvm_destroy_all_vms(void)
out:
mutex_unlock(&gzvm_list_lock);
}
+
+int gzvm_drv_debug_init(void)
+{
+ if (!debugfs_initialized())
+ return 0;
+
+ if (!gzvm_debugfs_dir && !debugfs_lookup("gzvm", gzvm_debugfs_dir))
+ gzvm_debugfs_dir = debugfs_create_dir("gzvm", NULL);
+
+ return 0;
+}
+
+void gzvm_drv_debug_exit(void)
+{
+ if (gzvm_debugfs_dir && debugfs_lookup("gzvm", gzvm_debugfs_dir))
+ debugfs_remove_recursive(gzvm_debugfs_dir);
+}
diff --git a/include/linux/soc/mediatek/gzvm_drv.h b/include/linux/soc/mediatek/gzvm_drv.h
index 2e5e9c67cfa5..e123787cd70d 100644
--- a/include/linux/soc/mediatek/gzvm_drv.h
+++ b/include/linux/soc/mediatek/gzvm_drv.h
@@ -47,6 +47,9 @@

#define GZVM_BLOCK_BASED_DEMAND_PAGE_SIZE (2 * 1024 * 1024) /* 2MB */

+#define GZVM_MAX_DEBUGFS_DIR_NAME_SIZE 20
+#define GZVM_MAX_DEBUGFS_VALUE_SIZE 20
+
enum gzvm_demand_paging_mode {
GZVM_FULLY_POPULATED = 0,
GZVM_DEMAND_PAGING = 1,
@@ -106,6 +109,11 @@ struct gzvm_pinned_page {
u64 ipa;
};

+struct gzvm_vm_stat {
+ u64 protected_hyp_mem;
+ u64 protected_shared_mem;
+};
+
/**
* struct gzvm: the following data structures are for data transferring between
* driver and hypervisor, and they're aligned with hypervisor definitions.
@@ -128,6 +136,8 @@ struct gzvm_pinned_page {
* page mailbox at the same time
* @pinned_pages: use rb-tree to record pin/unpin page
* @mem_lock: lock for memory operations
+ * @stat: information for VM memory statistics
+ * @debug_dir: debugfs directory node for VM memory statistics
*/
struct gzvm {
struct gzvm_vcpu *vcpus[GZVM_MAX_VCPUS];
@@ -158,6 +168,9 @@ struct gzvm {

struct rb_root pinned_pages;
struct mutex mem_lock;
+
+ struct gzvm_vm_stat stat;
+ struct dentry *debug_dir;
};

long gzvm_dev_ioctl_check_extension(struct gzvm *gzvm, unsigned long args);
@@ -179,6 +192,7 @@ int gzvm_arch_destroy_vm(u16 vm_id);
int gzvm_arch_map_guest(u16 vm_id, int memslot_id, u64 pfn, u64 gfn,
u64 nr_pages);
int gzvm_arch_map_guest_block(u16 vm_id, int memslot_id, u64 gfn, u64 nr_pages);
+int gzvm_arch_get_statistics(struct gzvm *gzvm);
int gzvm_vm_ioctl_arch_enable_cap(struct gzvm *gzvm,
struct gzvm_enable_cap *cap,
void __user *argp);
@@ -201,6 +215,9 @@ int gzvm_arch_vcpu_run(struct gzvm_vcpu *vcpu, __u64 *exit_reason);
int gzvm_arch_destroy_vcpu(u16 vm_id, int vcpuid);
int gzvm_arch_inform_exit(u16 vm_id);

+int gzvm_drv_debug_init(void);
+void gzvm_drv_debug_exit(void);
+
int gzvm_find_memslot(struct gzvm *vm, u64 gpa);
int gzvm_handle_page_fault(struct gzvm_vcpu *vcpu);
bool gzvm_handle_guest_exception(struct gzvm_vcpu *vcpu);
--
2.18.0

Next message: Yi-De Wu: "[PATCH v10 18/21] virt: geniezone: Add memory relinquish support"
Previous message: Yi-De Wu: "[PATCH v10 01/21] virt: geniezone: enable gzvm-ko in defconfig"
In reply to: Yi-De Wu: "[PATCH v10 01/21] virt: geniezone: enable gzvm-ko in defconfig"
Next in thread: Simon Horman: "Re: [PATCH v10 19/21] virt: geniezone: Provide individual VM memory statistics within debugfs"
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