[Xen-devel] [makedumpfile] makedumpfile port to Xen 4 (exclude_xen_user_domain)

["Trapp, Norbert" <norbert.trapp@xxxxxxxxxxxxxx>]

Hello,

 

makedumpfile can be used to save just the dom0 memory in case of a crash.

We need this feature to quickly restart systems with a huge amount of

(domU) memory. Unfortunately makedumpfile has not yet been ported to Xen 4.

So I gave it a try and I plan to send patches to the makedumpfile

project. The makedumpfile project leader asked me to also send the patches to

the xen-devel mailing list. Let me start with the code for determining

the dom0 pages in Xen 4. If you care please let me know about any faults or

improvements.

 

Thanks

Norbert

 

The function exclude_xen_user_domain() determines the dom0 and xen

pages and clears a bit in a bitmap for all other pages.

The function is_select_domain() determines whether the parameter is the pickled_id

of dom0.

 

#define BITS_PER_LONG 64

#define PG_shift(idx) (BITS_PER_LONG - (idx))

#define PG_mask(x, idx) (x ## UL << PG_shift(idx))

#define PGC_state_inuse PG_mask(0, 9)

#define PGC_allocated PG_mask(1, 1)

#define PGC_xen_heap PG_mask(1, 2)

#define PGC_state_free    PG_mask(3, 9)

 

int

exclude_xen_user_domain(void)

{

    int i;

    unsigned long count_info;

    unsigned int _domain;

    unsigned long page_info_addr;

    unsigned long long pfn, pfn_end;

    unsigned long long j, size;

    struct pt_load_segment *pls;

 

    for (i = 0; i < info->num_load_memory; i++) {

 

        pls = &info->pt_load_segments[i];

        pfn     = paddr_to_pfn(pls->phys_start);

        pfn_end = paddr_to_pfn(pls->phys_end);

        size    = pfn_end - pfn;

 

        for (j = 0; pfn < pfn_end; pfn++, j++) {

 

            page_info_addr = info->frame_table_vaddr + pfn * SIZE(page_info);

            if (!readmem(VADDR_XEN,

                  page_info_addr + OFFSET(page_info.count_info),

                  &count_info, sizeof(count_info))) {

                clear_bit_on_2nd_bitmap(pfn);

                continue;   /* page_info may not exist */

            }

            if (!readmem(VADDR_XEN,

                  page_info_addr + OFFSET(page_info._domain),

                  &_domain, sizeof(_domain))) {

                ERRMSG("Can't get page_info._domain.\n");

                return FALSE;

            }

 

            if (count_info & PGC_state_free) {

                clear_bit_on_2nd_bitmap(pfn);

                continue;

            }

            if (count_info & PGC_xen_heap) {

                continue;

            }

            if (count_info & PGC_allocated) {

                if (_domain == 0) {

                    continue;

                }

                if (is_select_domain(_domain)) {

                    continue;

                } else {

                    clear_bit_on_2nd_bitmap(pfn);

                    continue;

                }

            }

            if (count_info == PGC_state_inuse) {

                continue;

            }

            clear_bit_on_2nd_bitmap(pfn);

        }

    }

 

    return TRUE;

}

 

 

With kind regards

 

Norbert Trapp

PDG ES&S SWE OS 6

 

FUJITSU

Fujitsu Technology Solutions GmbH

Domagkstraße 28, D-80807 München, Germany

E-Mail: Norbert.Trapp@xxxxxxxxxxxxxx

Web: ts.fujitsu.com

Company details: ts.fujitsu.com/imprint

 

 

 

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