On 2014-03-18 17:37, Paolo Bonzini wrote: > Il 18/03/2014 17:23, Luiz Capitulino ha scritto: >> On Tue, 18 Mar 2014 15:36:45 +0100 >> Jan Kiszka <jan.kis...@siemens.com> wrote: >> >>>>> Right, this belongs in the "if (env->hflags & HF_LMA_MASK)" block. >>>>> >>>>> And the subject or description should mention that >>>>> x86_cpu_get_phys_page_debug was lacking support for 1G hugepages. >>>> >>>> To be honest, although the PS bit is set and that indicates a 1GB page, >>>> I didn't know Linux does that. I thought Linux would use 4KB pages for >>>> everything unless it's explicitly asked to use bigger pages. Also, >>>> note that >>>> I was using gdb to debug really early kernel boot code >>>> (start_kernel()). >>> >>> I could imagine that Linux initially creates a giant identity mapping >>> page table for the startup process and only later on switches to >>> fine-grained tables of 4K and 2M pages. Giant pages still require >>> hughtlbfs, IIRC. >>> >>>> >>>> I'd feel more confident to have such a changelog after I find out where >>>> exactly Linux sets that bit, but I won't have time in the next days. >>>> On the >>>> other hand, the patch does fix the problem to me. >>> >>> Don't worry about Linux (the code should work with any OS anyway), just >>> believe your reviewers. ;) Alternatively, check Intel IA32 SDM on page >>> table structures. >> >> OK, so you want me to change the subject? Anything else for v2? > > You only need to move the new code into the "if (env->hflags & > HF_LMA_MASK)", I think. The subject is ok.
Yes. Subject is fine, a reference to GB pages in the description would be nice-to-have. Jan -- Siemens AG, Corporate Technology, CT RTC ITP SES-DE Corporate Competence Center Embedded Linux
