kvm: Refactor handling of VM debugfs files

We can store reference to kvm_stats_debugfs_item instead of copying
its values to kvm_stat_data.
This allows us to remove duplicated code and usage of temporary
kvm_stat_data inside vm_stat_get et al.

Signed-off-by: Milan Pandurov <milanpa@amazon.de>
Reviewed-by: Alexander Graf <graf@amazon.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 528ab7a..5e2ec7e 100644 (file)
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1108,9 +1108,8 @@ enum kvm_stat_kind {
 };
 
 struct kvm_stat_data {
-       int offset;
-       int mode;
        struct kvm *kvm;
+       struct kvm_stats_debugfs_item *dbgfs_item;
 };
 
 struct kvm_stats_debugfs_item {
@@ -1119,6 +1118,10 @@ struct kvm_stats_debugfs_item {
        enum kvm_stat_kind kind;
        int mode;
 };
+
+#define KVM_DBGFS_GET_MODE(dbgfs_item)                                         \
+       ((dbgfs_item)->mode ? (dbgfs_item)->mode : 0644)
+
 extern struct kvm_stats_debugfs_item debugfs_entries[];
 extern struct dentry *kvm_debugfs_dir;
 

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 1a6d5eb..483c683 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -113,7 +113,7 @@ struct dentry *kvm_debugfs_dir;
 EXPORT_SYMBOL_GPL(kvm_debugfs_dir);
 
 static int kvm_debugfs_num_entries;
-static const struct file_operations *stat_fops_per_vm[];
+static const struct file_operations stat_fops_per_vm;
 
 static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
                           unsigned long arg);
@@ -650,11 +650,11 @@ static int kvm_create_vm_debugfs(struct kvm *kvm, int fd)
                        return -ENOMEM;
 
                stat_data->kvm = kvm;
-               stat_data->offset = p->offset;
-               stat_data->mode = p->mode ? p->mode : 0644;
+               stat_data->dbgfs_item = p;
                kvm->debugfs_stat_data[p - debugfs_entries] = stat_data;
-               debugfs_create_file(p->name, stat_data->mode, kvm->debugfs_dentry,
-                                   stat_data, stat_fops_per_vm[p->kind]);
+               debugfs_create_file(p->name, KVM_DBGFS_GET_MODE(p),
+                                   kvm->debugfs_dentry, stat_data,
+                                   &stat_fops_per_vm);
        }
        return 0;
 }
@@ -4010,8 +4010,9 @@ static int kvm_debugfs_open(struct inode *inode, struct file *file,
                return -ENOENT;
 
        if (simple_attr_open(inode, file, get,
-                            stat_data->mode & S_IWUGO ? set : NULL,
-                            fmt)) {
+                   KVM_DBGFS_GET_MODE(stat_data->dbgfs_item) & 0222
+                   ? set : NULL,
+                   fmt)) {
                kvm_put_kvm(stat_data->kvm);
                return -ENOMEM;
        }
@@ -4030,105 +4031,111 @@ static int kvm_debugfs_release(struct inode *inode, struct file *file)
        return 0;
 }
 
-static int vm_stat_get_per_vm(void *data, u64 *val)
+static int kvm_get_stat_per_vm(struct kvm *kvm, size_t offset, u64 *val)
 {
-       struct kvm_stat_data *stat_data = (struct kvm_stat_data *)data;
+       *val = *(ulong *)((void *)kvm + offset);
 
-       *val = *(ulong *)((void *)stat_data->kvm + stat_data->offset);
+       return 0;
+}
+
+static int kvm_clear_stat_per_vm(struct kvm *kvm, size_t offset)
+{
+       *(ulong *)((void *)kvm + offset) = 0;
 
        return 0;
 }
 
-static int vm_stat_clear_per_vm(void *data, u64 val)
+static int kvm_get_stat_per_vcpu(struct kvm *kvm, size_t offset, u64 *val)
 {
-       struct kvm_stat_data *stat_data = (struct kvm_stat_data *)data;
+       int i;
+       struct kvm_vcpu *vcpu;
 
-       if (val)
-               return -EINVAL;
+       *val = 0;
 
-       *(ulong *)((void *)stat_data->kvm + stat_data->offset) = 0;
+       kvm_for_each_vcpu(i, vcpu, kvm)
+               *val += *(u64 *)((void *)vcpu + offset);
 
        return 0;
 }
 
-static int vm_stat_get_per_vm_open(struct inode *inode, struct file *file)
+static int kvm_clear_stat_per_vcpu(struct kvm *kvm, size_t offset)
 {
-       __simple_attr_check_format("%llu\n", 0ull);
-       return kvm_debugfs_open(inode, file, vm_stat_get_per_vm,
-                               vm_stat_clear_per_vm, "%llu\n");
-}
+       int i;
+       struct kvm_vcpu *vcpu;
 
-static const struct file_operations vm_stat_get_per_vm_fops = {
-       .owner   = THIS_MODULE,
-       .open    = vm_stat_get_per_vm_open,
-       .release = kvm_debugfs_release,
-       .read    = simple_attr_read,
-       .write   = simple_attr_write,
-       .llseek  = no_llseek,
-};
+       kvm_for_each_vcpu(i, vcpu, kvm)
+               *(u64 *)((void *)vcpu + offset) = 0;
+
+       return 0;
+}
 
-static int vcpu_stat_get_per_vm(void *data, u64 *val)
+static int kvm_stat_data_get(void *data, u64 *val)
 {
-       int i;
+       int r = -EFAULT;
        struct kvm_stat_data *stat_data = (struct kvm_stat_data *)data;
-       struct kvm_vcpu *vcpu;
-
-       *val = 0;
 
-       kvm_for_each_vcpu(i, vcpu, stat_data->kvm)
-               *val += *(u64 *)((void *)vcpu + stat_data->offset);
+       switch (stat_data->dbgfs_item->kind) {
+       case KVM_STAT_VM:
+               r = kvm_get_stat_per_vm(stat_data->kvm,
+                                       stat_data->dbgfs_item->offset, val);
+               break;
+       case KVM_STAT_VCPU:
+               r = kvm_get_stat_per_vcpu(stat_data->kvm,
+                                         stat_data->dbgfs_item->offset, val);
+               break;
+       }
 
-       return 0;
+       return r;
 }
 
-static int vcpu_stat_clear_per_vm(void *data, u64 val)
+static int kvm_stat_data_clear(void *data, u64 val)
 {
-       int i;
+       int r = -EFAULT;
        struct kvm_stat_data *stat_data = (struct kvm_stat_data *)data;
-       struct kvm_vcpu *vcpu;
 
        if (val)
                return -EINVAL;
 
-       kvm_for_each_vcpu(i, vcpu, stat_data->kvm)
-               *(u64 *)((void *)vcpu + stat_data->offset) = 0;
+       switch (stat_data->dbgfs_item->kind) {
+       case KVM_STAT_VM:
+               r = kvm_clear_stat_per_vm(stat_data->kvm,
+                                         stat_data->dbgfs_item->offset);
+               break;
+       case KVM_STAT_VCPU:
+               r = kvm_clear_stat_per_vcpu(stat_data->kvm,
+                                           stat_data->dbgfs_item->offset);
+               break;
+       }
 
-       return 0;
+       return r;
 }
 
-static int vcpu_stat_get_per_vm_open(struct inode *inode, struct file *file)
+static int kvm_stat_data_open(struct inode *inode, struct file *file)
 {
        __simple_attr_check_format("%llu\n", 0ull);
-       return kvm_debugfs_open(inode, file, vcpu_stat_get_per_vm,
-                                vcpu_stat_clear_per_vm, "%llu\n");
+       return kvm_debugfs_open(inode, file, kvm_stat_data_get,
+                               kvm_stat_data_clear, "%llu\n");
 }
 
-static const struct file_operations vcpu_stat_get_per_vm_fops = {
-       .owner   = THIS_MODULE,
-       .open    = vcpu_stat_get_per_vm_open,
+static const struct file_operations stat_fops_per_vm = {
+       .owner = THIS_MODULE,
+       .open = kvm_stat_data_open,
        .release = kvm_debugfs_release,
-       .read    = simple_attr_read,
-       .write   = simple_attr_write,
-       .llseek  = no_llseek,
-};
-
-static const struct file_operations *stat_fops_per_vm[] = {
-       [KVM_STAT_VCPU] = &vcpu_stat_get_per_vm_fops,
-       [KVM_STAT_VM]   = &vm_stat_get_per_vm_fops,
+       .read = simple_attr_read,
+       .write = simple_attr_write,
+       .llseek = no_llseek,
 };
 
 static int vm_stat_get(void *_offset, u64 *val)
 {
        unsigned offset = (long)_offset;
        struct kvm *kvm;
-       struct kvm_stat_data stat_tmp = {.offset = offset};
        u64 tmp_val;
 
        *val = 0;
        mutex_lock(&kvm_lock);
        list_for_each_entry(kvm, &vm_list, vm_list) {
-               stat_tmp.kvm = kvm;
-               vm_stat_get_per_vm((void *)&stat_tmp, &tmp_val);
+               kvm_get_stat_per_vm(kvm, offset, &tmp_val);
                *val += tmp_val;
        }
        mutex_unlock(&kvm_lock);
@@ -4139,15 +4146,13 @@ static int vm_stat_clear(void *_offset, u64 val)
 {
        unsigned offset = (long)_offset;
        struct kvm *kvm;
-       struct kvm_stat_data stat_tmp = {.offset = offset};
 
        if (val)
                return -EINVAL;
 
        mutex_lock(&kvm_lock);
        list_for_each_entry(kvm, &vm_list, vm_list) {
-               stat_tmp.kvm = kvm;
-               vm_stat_clear_per_vm((void *)&stat_tmp, 0);
+               kvm_clear_stat_per_vm(kvm, offset);
        }
        mutex_unlock(&kvm_lock);
 
@@ -4160,14 +4165,12 @@ static int vcpu_stat_get(void *_offset, u64 *val)
 {
        unsigned offset = (long)_offset;
        struct kvm *kvm;
-       struct kvm_stat_data stat_tmp = {.offset = offset};
        u64 tmp_val;
 
        *val = 0;
        mutex_lock(&kvm_lock);
        list_for_each_entry(kvm, &vm_list, vm_list) {
-               stat_tmp.kvm = kvm;
-               vcpu_stat_get_per_vm((void *)&stat_tmp, &tmp_val);
+               kvm_get_stat_per_vcpu(kvm, offset, &tmp_val);
                *val += tmp_val;
        }
        mutex_unlock(&kvm_lock);
@@ -4178,15 +4181,13 @@ static int vcpu_stat_clear(void *_offset, u64 val)
 {
        unsigned offset = (long)_offset;
        struct kvm *kvm;
-       struct kvm_stat_data stat_tmp = {.offset = offset};
 
        if (val)
                return -EINVAL;
 
        mutex_lock(&kvm_lock);
        list_for_each_entry(kvm, &vm_list, vm_list) {
-               stat_tmp.kvm = kvm;
-               vcpu_stat_clear_per_vm((void *)&stat_tmp, 0);
+               kvm_clear_stat_per_vcpu(kvm, offset);
        }
        mutex_unlock(&kvm_lock);
 
@@ -4259,9 +4260,8 @@ static void kvm_init_debug(void)
 
        kvm_debugfs_num_entries = 0;
        for (p = debugfs_entries; p->name; ++p, kvm_debugfs_num_entries++) {
-               int mode = p->mode ? p->mode : 0644;
-               debugfs_create_file(p->name, mode, kvm_debugfs_dir,
-                                   (void *)(long)p->offset,
+               debugfs_create_file(p->name, KVM_DBGFS_GET_MODE(p),
+                                   kvm_debugfs_dir, (void *)(long)p->offset,
                                    stat_fops[p->kind]);
        }
 }