On 11.02.20 09:48, Janosch Frank wrote: > On 2/10/20 1:56 PM, Christian Borntraeger wrote: >> >> >> On 10.02.20 13:50, Cornelia Huck wrote: >>> On Mon, 10 Feb 2020 13:06:19 +0100 >>> Christian Borntraeger <borntraeger@xxxxxxxxxx> wrote: >>> >>>> What about the following. I will rip out RC and RRC but add >>>> a 32bit flags field (which must be 0) and 3*64 bit reserved. >>> >>> Probably dumb question: How are these new fields supposed to be used? >> >> This was planned for error handling in QEMU. As we have no user of rc/rrc >> yet, I have ripped that out and added a flag field + 16 bytes of reserved. >> Usage is as usual flags must be 0. When flags!=0 the reserved fields will >> have a new meaning. >> > > I want to have the rcs because right now we would only output the return > value of the ioctl and most UV error codes are mapped to -EINVAL. So if > an error occurs, admins would need to match up the crashed VM with the > UV debugfs files which might not even exist if debugfs is not mounted... > > That's also one of the reasons I like having separate create calls for > VM and VCPUs. Janosch convinced me that we need rc and rrc for some calls. For example the set secure configuration parameter passes along the header from the guest image to the hardware. There are now different errors possible, for example wrong key, wrong list of requirements etc. Userspace needs to know that to provide proper error messages. I will try to build something as clean as possible.
