On 13.12.19 14:07, Milan Pandurov wrote:
> 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@xxxxxxxxx>
> Reviewed-by: Alexander Graf <graf@xxxxxxxxxx>
>
I gave this a quick spin and it still seems to work.
> ---
> v1 -> v2:
> - fix compile issues
> - add reference to kvm_stats_debugfs_item in kvm_stat_data
> - return -EINVAL when writing !0
> - use explicit switch case instead of ops indirection
> - fix checkpatch warning: Change S_IWUGO to 0222
>
> v2 -> v3:
> - remove unused kvm_stat_ops
> - fix style issues
>
> v3 -> v4:
> - revert: Change S_IWUGO to 0222
>
> v4 -> v5:
> - fix checkpatch warning: Change S_IWUGO to 0222
> ---
> include/linux/kvm_host.h | 7 +-
> virt/kvm/kvm_main.c | 142 +++++++++++++++++++--------------------
> 2 files changed, 76 insertions(+), 73 deletions(-)
>
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index 7ed1e2f8641e..d3f2c0eae857 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -1109,9 +1109,8 @@ 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 {
> @@ -1120,6 +1119,10 @@ 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 00268290dcbd..0ebd6aa95671 100644
> --- 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;
> }
> @@ -4013,8 +4013,9 @@ 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;
> }
> @@ -4033,105 +4034,111 @@ 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);
> @@ -4142,15 +4149,13 @@ 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);
>
> @@ -4163,14 +4168,12 @@ 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);
> @@ -4181,15 +4184,13 @@ 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);
>
> @@ -4262,9 +4263,8 @@ 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]);
> }
> }
>
