Re: [Crash-utility] [PATCH] vmware_vmss: read vCPUs regs and show them in 'bt'

On Wed, Mar 21, 2018 at 10:44:47AM -0400, Dave Anderson wrote: > > > ----- Original Message ----- > > VMSS dump files contain the state of each vCPU at the time of suspending > > the VM. This change enables 'crash' to read some relevant registers from > > each vCPU state and display them in 'bt'. > > That's very helpful. I'm not sure why VMware never did anything like that > in the original patch. > > And now that there finally is a VMSS_DUMPFILE() indicator, it would be helpful > to at least display *something* w/respect to the dumpfile contents as viewed from > "help -D". If you bring up the session with "crash -d1" you will see a bunch > of stuff from the dumpfile, although I'm not sure whether all of it would be > useful during runtime. But if nothing else, at least indicate what kind of > dumpfile it is, and anything else that might be useful. > > Also, I just noticed that original patch from VMware does not display the > VMWARE_VMSS bit in pc->flag as show by "help -p". Can you add that too? I didn't pay any attention to the "help" command. I'm going to implement the VMWARE_VMSS bit in pc->flag, and also the "help -r" output, which seems quite straightforward having all the registers already properly placed in vmssregs64.

As for "help -D", I think we could implement a function that iterates through groups and tags present in the VMSS, printing names, sizes and values (for non-block tags). Basically, it'd be the same thing that "vmware_vmss_init" does, but unconditionally printing the info without touching anything else. Does this makes sense to you?

> > calculation for VMSS dump files. > > Will that require the KASLR helper patch as a prerequisite? Yes, otherwise we'd need to duplicate "calc_kaslr_offset" and all the related functions.