On 14/06/21 23:21, Jing Zhang wrote:
- /* Copy kvm stats values */
- copylen = header->header.data_offset + size_stats - pos;
- copylen = min(copylen, remain);
- if (copylen > 0) {
src = stats + pos - header->header.data_offset;if (copy_to_user(dest, src, copylen))return -EFAULT;remain -= copylen;pos += copylen;dest += copylen;- }
Hi Jing,
this code is causing usercopy warnings because the statistics are not part of the vcpu slab's usercopy region. You need to move struct kvm_vcpu_stat next to struct kvm_vcpu_arch, and adjust the call to kmem_cache_create_usercopy in kvm_init.
Can you post a new version of the series, and while you are at it explain the rationale for binary stats in the commit message for this patch? This should include:
- the problem statement (e.g. frequency of the accesses)
- what are the benefits compared to debugfs
- why the schema is included in the file descriptor as well
You can probably find a lot or all of the information in my emails from the last couple days, but you might also have other breadcrumbs from Google's internal implementation of binary stats.
Thanks,
Paolo