Add support for filtering out user pages under Xen4
Subsystems (2)
PATCH v3 8/9 Add support for filtering out user pages under Xen4
In Xen-4.0+, usage of a page must be determined from its PGC_xxx flags, which are stored in the highest bits of the _count field of struct page_info.
Let's keep the original function for Xen3 only and add a new function for walking the pages under Xen4. This avoids adding many new conditionals to the inner loop and also makes the logic easier to follow for all Xen versions.
--- makedumpfile.c | 102 +++++++++++++++++++++++++++++++++++++++++++++++++++++---- makedumpfile.h | 25 +++++++++++++ 2 files changed, 121 insertions(+), 6 deletions(-)
makedumpfile.h +25 -0
@@ -78,6 +78,31 @@ int get_mem_type(void);#define LSEEKED_PDATA (3)/* +* Xen page flags +*/ +#define BITS_PER_BYTE (8) +#define BITS_PER_LONG (BITS_PER_BYTE * sizeof(long)) +#define PG_shift (idx) (BITS_PER_LONG - (idx)) +#define PG_mask (x, idx) (x ## UL << PG_shift(idx)) +/* Cleared when the owning guest 'frees' this page. */ +#define PGC_allocated PG_mask(1, 1) +/* Page is Xen heap? */ +#define PGC_xen_heap PG_mask(1, 2) +/* Page is broken? */ +#define PGC_broken PG_mask(1, 7) +/* Mutually-exclusive page states: { inuse, offlining, offlined, free }. */ +#define PGC_state PG_mask(3, 9) +#define PGC_state_inuse PG_mask(0, 9) +#define PGC_state_offlining PG_mask(1, 9) +#define PGC_state_offlined PG_mask(2, 9) +#define PGC_state_free PG_mask(3, 9) +#define page_state_is (ci, st) (((ci)&PGC_state) == PGC_state_##st) + +/* Count of references to this frame. */ +#define PGC_count_width PG_shift(9) +#define PGC_count_mask ((1UL<<PGC_count_width)-1) + +/* * Memory flags */ #define MEMORY_PAGETABLE_4L (1 << 0)
makedumpfile.c +32 -4
@@ -5719,7 +5719,7 @@ is_select_domain(unsigned int id) }int -exclude_xen_user_domain (void ) +exclude_xen3_user_domain (void ) {int i;unsigned int count_info, _domain;
@@ -5728,9 +5728,6 @@ exclude_xen_user_domain(void)unsigned long long phys_start, phys_end;unsigned long long pfn, pfn_end;unsigned long long j, size; -struct timeval tv_start; - -gettimeofday (&tv_start,NULL );/* * NOTE: the first half of bitmap is not used for Xen extraction
@@ -5781,13 +5778,106 @@ exclude_xen_user_domain(void) } } +return TRUE; +} + +int +exclude_xen4_user_domain (void ) +{ +int i; +unsigned long count_info; +unsigned int _domain; +unsigned int num_pt_loads =get_num_pt_loads (); +unsigned long page_info_addr; +unsigned long long phys_start, phys_end; +unsigned long long pfn, pfn_end; +unsigned long long j, size; + +/* +* NOTE: the first half of bitmap is not used for Xen extraction +*/ +for (i =0 ;get_pt_load (i, &phys_start, &phys_end,NULL ,NULL ); i++) { + +print_progress (PROGRESS_XEN_DOMAIN , i, num_pt_loads); + + pfn =paddr_to_pfn (phys_start); + pfn_end =paddr_to_pfn (phys_end); + size = pfn_end - pfn; + +for (j =0 ; pfn < pfn_end; pfn++, j++) { +print_progress (PROGRESS_XEN_DOMAIN , j + (size * i), + size * num_pt_loads); + + 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 */
+ }
+
+ /* always keep Xen heap pages */
+ if (count_info & PGC_xen_heap)
+ continue;
+
+ /* delete free, offlined and broken pages */
+ if (page_state_is(count_info, free) ||
+ page_state_is(count_info, offlined) ||
+ count_info & PGC_broken) {
+ clear_bit_on_2nd_bitmap(pfn);
+ continue;
+ }
+
+ /* keep inuse pages not allocated to any domain
+ * this covers e.g. Xen static data
+ */
+ if (! (count_info & PGC_allocated))
+ continue;
+
+ /* Need to check the domain
+ * keep:
+ * - anonymous (_domain == 0), or
+ * - selected domain page
+ */
+ 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 (_domain == 0)
+ continue;
+ if (is_select_domain(_domain))
+ continue;
+ clear_bit_on_2nd_bitmap(pfn);
+ }
+ }
+
+ return TRUE;
+}
+
+int
+exclude_xen_user_domain(void)
+{
+ struct timeval tv_start;
+ int ret;
+
+ gettimeofday(&tv_start, NULL);
+
+ if (info->xen_crash_info.com &&
+ info->xen_crash_info.com->xen_major_version >= 4)
+ ret = exclude_xen4_user_domain();
+ else
+ ret = exclude_xen3_user_domain();
+
/*
* print [100 %]
*/
- print_progress(PROGRESS_XEN_DOMAIN, num_pt_loads, num_pt_loads);
+ print_progress(PROGRESS_XEN_DOMAIN, 1, 1);
print_execution_time(PROGRESS_XEN_DOMAIN, &tv_start);
- return TRUE;
+ return ret;
}
int
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Hello Petr,
I'm sorry for having kept you waiting.
I have a small comment for this patch.
Quoted 21 lines · On Fri, 24 Aug 2012 17:43:23 +0200 Petr Tesarik <[email protected]> wrote:
In Xen-4.0+, usage of a page must be determined from its
PGC_xxxflags, which are stored in the highest bits of the_countfield of structpage_info.Let's keep the original function for Xen3 only and add a new function for walking the pages under Xen4. This avoids adding many new conditionals to the inner loop and also makes the logic easier to follow for all Xen versions.
Signed-off-by Norbert Trapp <[email protected]>Signed-off-by Petr Tesarik <[email protected]>--- makedumpfile.c | 102 +++++++++++++++++++++++++++++++++++++++++++++++++++++---- makedumpfile.h | 25 +++++++++++++ 2 files changed, 121 insertions(+), 6 deletions(-)
makedumpfile.h int get_mem_type(void); · line 84
Quoted 7 lines
makedumpfile.h +4
-0@@ -78,6 +78,31 @@ int get_mem_type(void);#define LSEEKED_PDATA (3)/* +* Xen page flags +*/ +#define BITS_PER_BYTE (8) +#define BITS_PER_LONG (BITS_PER_BYTE * sizeof(long))
BITPERBYTE is already defined as meaning the same as BITS_PER_BYTE, so I will change this patch to use BITPERBYTE instead of BITS_PER_BYTE when merging.
makedumpfile.h:
164
165 #define BITPERBYTE (8)
166 #define PGMM_CACHED (512)
Thanks
Atsushi Kumagai
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