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Re: [PATCH 4/9] xen/arm: static memory initialization
Hi Penny,
On 07/06/2021 03:43, Penny Zheng wrote:
This patch introduces static memory initialization, during system RAM boot up.
The word "RAM" looks spurious.
New func init_staticmem_pages is responsible for static memory initialization.
s/New func/The new function/
Helper free_staticmem_pages is the equivalent of free_heap_pages, to free
nr_mfns pages of static memory.
This commit defines a new helper free_page to extract common code between
free_heap_pages and free_staticmem_pages, like following the same cache/TLB
coherency policy.
For each page, free_staticmem_pages includes the following extra steps to
initialize:
1. change page state from inuse to free state and grant PGC_reserved.
I think you mean "set" rather than "grant".
2. scrub the page in need synchronously.
Can you explain why this is necessary?
Signed-off-by: Penny Zheng <penny.zheng@xxxxxxx>
---
changes v2:
- rename to nr_mfns
- extract common code from free_heap_pages and free_staticmem_pages
- remove dead codes in other archs, including move some to arm-specific file,
and put some under CONFIG_ARM
- mark free_staticmem_pages __init
---
xen/arch/arm/setup.c | 27 ++++++++++++++
I think it would be best to split the arm use in a separate patch.
xen/common/page_alloc.c | 78 +++++++++++++++++++++++++++++++++--------
xen/include/xen/mm.h | 6 ++++
3 files changed, 97 insertions(+), 14 deletions(-)
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 00aad1c194..daafea0abb 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -611,6 +611,30 @@ static void __init init_pdx(void)
}
}
+/* Static memory initialization */
+static void __init init_staticmem_pages(void)
+{
+ int bank;
+
+ /*
+ * TODO: Considering NUMA-support scenario.
+ */
+ for ( bank = 0 ; bank < bootinfo.static_mem.nr_banks; bank++ )
+ {
+ paddr_t bank_start = bootinfo.static_mem.bank[bank].start;
+ paddr_t bank_size = bootinfo.static_mem.bank[bank].size;
+ paddr_t bank_end = bank_start + bank_size;
+
+ bank_start = round_pgup(bank_start);
+ bank_end = round_pgdown(bank_end);
+ if ( bank_end <= bank_start )
+ return;
+
+ free_staticmem_pages(maddr_to_page(bank_start),
+ (bank_end - bank_start) >> PAGE_SHIFT, false);
+ }
+}
+
#ifdef CONFIG_ARM_32
static void __init setup_mm(void)
{
@@ -872,6 +896,9 @@ void __init start_xen(unsigned long boot_phys_offset,
cmdline_parse(cmdline);
setup_mm();
+ /* If exists, Static Memory Initialization. */
+ if ( bootinfo.static_mem.nr_banks > 0 )
This check seems a pointless because init_staticmem_pages() is already
able to cope with nr_banks == 0.
+ init_staticmem_pages();
I would prefer if this is folded in setup_mm().
/* Parse the ACPI tables for possible boot-time configuration */
acpi_boot_table_init();
diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
index 958ba0cd92..8c00262c04 100644
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -1376,6 +1376,37 @@ bool scrub_free_pages(void)
return node_to_scrub(false) != NUMA_NO_NODE;
}
+static void free_page(struct page_info *pg, bool need_scrub)
+{
+ mfn_t mfn = page_to_mfn(pg);
+
+ /* If a page has no owner it will need no safety TLB flush. */
+ pg->u.free.need_tlbflush = (page_get_owner(pg) != NULL);
+ if ( pg->u.free.need_tlbflush )
+ page_set_tlbflush_timestamp(pg);
+
+ /* This page is not a guest frame any more. */
+ page_set_owner(pg, NULL); /* set_gpfn_from_mfn snoops pg owner */
+ set_gpfn_from_mfn(mfn_x(mfn), INVALID_M2P_ENTRY);
+
+#ifdef CONFIG_ARM
To echo what Jan already wrote, I am not in favor of adding new #ifdef
CONFIG_<arch> in common code. I would expect the logic for static memory
to be the same for each arch, so this should be protected with a generic
Kconfig.
+ if ( pg->count_info & PGC_reserved )
+ {
+ /* TODO: asynchronous scrubbing. */
+ if ( need_scrub )
+ scrub_one_page(pg);
+ return;
+ }
+#endif
+ if ( need_scrub )
+ {
+ pg->count_info |= PGC_need_scrub;
+ poison_one_page(pg);
+ }
+
+ return;
+}
+
/* Free 2^@order set of pages. */
static void free_heap_pages(
struct page_info *pg, unsigned int order, bool need_scrub)
@@ -1425,20 +1456,7 @@ static void free_heap_pages(
BUG();
}
- /* If a page has no owner it will need no safety TLB flush. */
- pg[i].u.free.need_tlbflush = (page_get_owner(&pg[i]) != NULL);
- if ( pg[i].u.free.need_tlbflush )
- page_set_tlbflush_timestamp(&pg[i]);
-
- /* This page is not a guest frame any more. */
- page_set_owner(&pg[i], NULL); /* set_gpfn_from_mfn snoops pg owner */
- set_gpfn_from_mfn(mfn_x(mfn) + i, INVALID_M2P_ENTRY);
-
- if ( need_scrub )
- {
- pg[i].count_info |= PGC_need_scrub;
- poison_one_page(&pg[i]);
- }
+ free_page(&pg[i], need_scrub);
}
avail[node][zone] += 1 << order;
@@ -1512,6 +1530,38 @@ static void free_heap_pages(
spin_unlock(&heap_lock);
}
+#ifdef CONFIG_STATIC_ALLOCATION
+/* Equivalent of free_heap_pages to free nr_mfns pages of static memory. */
+void __init free_staticmem_pages(struct page_info *pg, unsigned long nr_mfns,
+ bool need_scrub)
+{
+ mfn_t mfn = page_to_mfn(pg);
+ unsigned long i;
+
+ for ( i = 0; i < nr_mfns; i++ )
+ {
+ switch ( pg[i].count_info & PGC_state )
+ {
+ case PGC_state_inuse:
+ BUG_ON(pg[i].count_info & PGC_broken);
+ /* Mark it free and reserved. */
+ pg[i].count_info = PGC_state_free | PGC_reserved;
+ break;
+
+ default:
+ printk(XENLOG_ERR
+ "Page state shall be only in PGC_state_inuse. "
+ "pg[%lu] MFN %"PRI_mfn" count_info=%#lx
tlbflush_timestamp=%#x.\n",
+ i, mfn_x(mfn) + i,
+ pg[i].count_info,
+ pg[i].tlbflush_timestamp);
+ BUG();
+ }
+
+ free_page(&pg[i], need_scrub);
+ }
+}
+#endif
/*
* Following rules applied for page offline:
diff --git a/xen/include/xen/mm.h b/xen/include/xen/mm.h
index 667f9dac83..df25e55966 100644
--- a/xen/include/xen/mm.h
+++ b/xen/include/xen/mm.h
@@ -85,6 +85,12 @@ bool scrub_free_pages(void);
} while ( false )
#define FREE_XENHEAP_PAGE(p) FREE_XENHEAP_PAGES(p, 0)
+#ifdef CONFIG_ARM
+/* Static Allocation */
+void free_staticmem_pages(struct page_info *pg, unsigned long nr_mfns,
+ bool need_scrub);
+#endif
+
/* Map machine page range in Xen virtual address space. */
int map_pages_to_xen(
unsigned long virt,
--
Julien Grall
|
