From a991063ce57684a2259688886643cf1c430f8188 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Fri, 11 Oct 2019 11:59:48 +0200 Subject: kvm: x86, powerpc: do not allow clearing largepages debugfs entry commit 833b45de69a6016c4b0cebe6765d526a31a81580 upstream. The largepages debugfs entry is incremented/decremented as shadow pages are created or destroyed. Clearing it will result in an underflow, which is harmless to KVM but ugly (and could be misinterpreted by tools that use debugfs information), so make this particular statistic read-only. Signed-off-by: Paolo Bonzini Signed-off-by: Thomas Gleixner Cc: kvm-ppc@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- virt/kvm/kvm_main.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'virt') diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 4a584a575221..0c578a1929b8 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -616,8 +616,9 @@ static int kvm_create_vm_debugfs(struct kvm *kvm, int fd) stat_data->kvm = kvm; stat_data->offset = p->offset; + stat_data->mode = p->mode ? p->mode : 0644; kvm->debugfs_stat_data[p - debugfs_entries] = stat_data; - debugfs_create_file(p->name, 0644, kvm->debugfs_dentry, + debugfs_create_file(p->name, stat_data->mode, kvm->debugfs_dentry, stat_data, stat_fops_per_vm[p->kind]); } return 0; @@ -3714,7 +3715,9 @@ static int kvm_debugfs_open(struct inode *inode, struct file *file, if (!refcount_inc_not_zero(&stat_data->kvm->users_count)) return -ENOENT; - if (simple_attr_open(inode, file, get, set, fmt)) { + if (simple_attr_open(inode, file, get, + stat_data->mode & S_IWUGO ? set : NULL, + fmt)) { kvm_put_kvm(stat_data->kvm); return -ENOMEM; } @@ -3962,7 +3965,8 @@ static void kvm_init_debug(void) kvm_debugfs_num_entries = 0; for (p = debugfs_entries; p->name; ++p, kvm_debugfs_num_entries++) { - debugfs_create_file(p->name, 0644, kvm_debugfs_dir, + int mode = p->mode ? p->mode : 0644; + debugfs_create_file(p->name, mode, kvm_debugfs_dir, (void *)(long)p->offset, stat_fops[p->kind]); } -- cgit v1.2.3