Messages in this thread | | | Date | Wed, 18 Mar 2009 22:39:39 +0800 | From | Américo Wang <> | Subject | Re: [PATCH 2/2] ptrace_vm: ptrace for syscall emulation virtual machines |
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On Mon, Mar 16, 2009 at 01:17:32PM +0100, Renzo Davoli wrote: >Dear Cong, > >Thank you for the detailed analysis of the code. >I'll change the code taking care of your observations asap.
You are so welcome. :)
> >On Mon, Mar 16, 2009 at 04:15:08PM +0800, Am??rico Wang wrote: >> >I have updated the patch, now it should be (more) consistent >> >with the Coding Style specifications. >> You can use scripts/checkpatch.pl to check it before sending. >I read the coding style document and I used the perl script. >However, the script is not able to cope with all the style specifications >and I may have missed something more. >> >> >UML tests at startup which features are provided and uses PTRACE_VM or >> >PTRACE_SYSEMU (or nothing). PTRACE_VM and/or PTRACE_SYSEMU support can be >> >disabled by command line flags. >> So what? PTRACE_VM is only supported in UML with this patch, >> UML still has to use PTRACE_SYSEMU on x86_32. >> >> Am I missing something? :) >This patch [2/2] is for UML (host and guest). Patch #1 provides PTRACE_VM >for all the architectures supporting ptrace via tracehook. >By applying both patches PTRACE_VM is available in the following architectures: >x86*, sparc*, s390, powerpc*, ia64, sh* and um. >(I have not tested all these architectures, but the patch applies to the core ptrace >code, shared by all of them).
Ok then. I am not familiar with tracehooks.
>Ptrace_vm then provides the same speedup of PTRACE_SYSEMU extending its support: >- to other architectures: ports of UML or similar code for other architectures can >use it >- to other applications: PTRACE_SYSEMU supports the virtualization of all the system calls >while by PTRACE_VM the VM monitor can virtualize some of the system calls, depending on >some condition e.g. the value of a parameter. It is possible in this way give a faster >implementation to partial virtual machines like my umview. > >With patch #2 user-mode linux also uses ptrace_vm where available. >
Thanks for your explanations!
-- Do what you love, f**k the rest! F**k the regulations!
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