|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v4 7/9] xen/arm: Implement virtual-linear page table for guest p2m mapping in live migration
Implement vlpt (virtual-linear page table) for fast accessing of 3rd
PTE of guest p2m. When creating a mapping for vlpt, just copy the
1st level PTE of guest p2m to the xen's 2nd level PTE. Then the mapping
becomes the following:
xen's 1st PTE -->
xen's 2nd PTE (which is the same as 1st PTE of guest p2m) -->
guest p2m's 2nd PTE -->
guest p2m's 3rd PTE (the memory contents where the vlpt points)
For more info about vlpt, see:
http://www.technovelty.org/linux/virtual-linear-page-table.html
This function is used in dirty-page tracing: when domU write-fault is trapped
by xen,
xen can immediately locate the 3rd PTE of guest p2m.
Signed-off-by: Jaeyong Yoo <jaeyong.yoo@xxxxxxxxxxx>
---
xen/arch/arm/mm.c | 78 ++++++++++++++++++++++++++++++++++++++++++++
xen/include/asm-arm/config.h | 6 ++++
xen/include/asm-arm/domain.h | 7 ++++
xen/include/asm-arm/mm.h | 22 +++++++++++++
4 files changed, 113 insertions(+)
diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 120eae8..98edbc9 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -1382,6 +1382,84 @@ int is_iomem_page(unsigned long mfn)
return 1;
return 0;
}
+
+/* flush the vlpt area */
+static void flush_vlpt(struct domain *d)
+{
+ int flush_size;
+ flush_size = (d->arch.dirty.second_lvl_end -
+ d->arch.dirty.second_lvl_start) << SECOND_SHIFT;
+ /* flushing the 3rd level mapping */
+ flush_xen_data_tlb_range_va(VIRT_LIN_P2M_START,
+ flush_size);
+}
+
+/* restore the xen page table for vlpt mapping for domain d */
+void restore_vlpt(struct domain *d)
+{
+ int i, j = 0;
+ int need_flush = 0;
+
+ for ( i = d->arch.dirty.second_lvl_start;
+ i < d->arch.dirty.second_lvl_end;
+ ++i, ++j )
+ {
+ if ( xen_second[i].bits != d->arch.dirty.second_lvl[j].bits )
+ {
+ write_pte(&xen_second[i], d->arch.dirty.second_lvl[j]);
+ need_flush = 1;
+ }
+ }
+
+ if ( need_flush ) flush_vlpt(d);
+}
+
+/* setting up the xen page table for vlpt mapping for domain d */
+void prepare_vlpt(struct domain *d)
+{
+ int xen_second_linear_base;
+ int gp2m_start_index, gp2m_end_index;
+ struct p2m_domain *p2m = &d->arch.p2m;
+ struct page_info *second_lvl_page;
+ vaddr_t gma_start = 0;
+ vaddr_t gma_end = 0;
+ lpae_t *first;
+ int i, j;
+
+ xen_second_linear_base = second_linear_offset(VIRT_LIN_P2M_START);
+ get_gma_start_end(d, &gma_start, &gma_end);
+
+ gp2m_start_index = gma_start >> FIRST_SHIFT;
+ gp2m_end_index = (gma_end >> FIRST_SHIFT) + 1;
+
+ second_lvl_page = alloc_domheap_page(NULL, 0);
+ d->arch.dirty.second_lvl = map_domain_page_global(
+ page_to_mfn(second_lvl_page) );
+
+ first = __map_domain_page(p2m->first_level);
+ for ( i = gp2m_start_index, j = 0; i < gp2m_end_index; ++i, ++j )
+ {
+ write_pte(&xen_second[xen_second_linear_base+i],
+ first[i]);
+
+ /* we copy the mapping into domain's structure as a reference in case
+ * of the context switch (used in restore_vlpt) */
+ d->arch.dirty.second_lvl[j] = first[i];
+ }
+ unmap_domain_page(first);
+
+ /* storing the start and end index */
+ d->arch.dirty.second_lvl_start = xen_second_linear_base + gp2m_start_index;
+ d->arch.dirty.second_lvl_end = xen_second_linear_base + gp2m_end_index;
+
+ flush_vlpt(d);
+}
+
+void cleanup_vlpt(struct domain *d)
+{
+ unmap_domain_page_global(d->arch.dirty.second_lvl);
+}
+
/*
* Local variables:
* mode: C
diff --git a/xen/include/asm-arm/config.h b/xen/include/asm-arm/config.h
index 9e395c2..47fc26e 100644
--- a/xen/include/asm-arm/config.h
+++ b/xen/include/asm-arm/config.h
@@ -87,6 +87,7 @@
* 0 - 8M <COMMON>
*
* 32M - 128M Frametable: 24 bytes per page for 16GB of RAM
+ * 128M - 256M Virtual-linear mapping to P2M table
* 256M - 1G VMAP: ioremap and early_ioremap use this virtual address
* space
*
@@ -132,6 +133,9 @@
#define VMAP_VIRT_END XENHEAP_VIRT_START
+#define VIRT_LIN_P2M_START _AT(vaddr_t,0x08000000)
+#define VIRT_LIN_P2M_END VMAP_VIRT_START
+
#define DOMHEAP_ENTRIES 1024 /* 1024 2MB mapping slots */
/* Number of domheap pagetable pages required at the second level (2MB
mappings) */
@@ -158,6 +162,8 @@
#define HYPERVISOR_VIRT_END DIRECTMAP_VIRT_END
+/*TODO (ARM_64): define VIRT_LIN_P2M_START VIRT_LIN_P2M_END */
+
#endif
/* Fixmap slots */
diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
index 755c7af..7e7743a 100644
--- a/xen/include/asm-arm/domain.h
+++ b/xen/include/asm-arm/domain.h
@@ -112,6 +112,13 @@ struct arch_domain
spinlock_t lock;
} vuart;
+ /* dirty-page tracing */
+ struct {
+ int second_lvl_start; /* for context switch */
+ int second_lvl_end;
+ lpae_t *second_lvl;
+ } dirty;
+
struct dt_mem_info map_domain;
spinlock_t map_lock;
} __cacheline_aligned;
diff --git a/xen/include/asm-arm/mm.h b/xen/include/asm-arm/mm.h
index 021e8d6..b9cbcf2 100644
--- a/xen/include/asm-arm/mm.h
+++ b/xen/include/asm-arm/mm.h
@@ -344,6 +344,28 @@ static inline void put_page_and_type(struct page_info
*page)
void get_gma_start_end(struct domain *d, vaddr_t *start, vaddr_t *end);
+/* vlpt (virtual linear page table) related functions */
+void prepare_vlpt(struct domain *d);
+void cleanup_vlpt(struct domain *d);
+void restore_vlpt(struct domain *d);
+
+/* calculate the xen's virtual address for accessing the leaf PTE of
+ * a given address (GPA) */
+static inline lpae_t * get_vlpt_3lvl_pte(vaddr_t addr)
+{
+ unsigned long ipa_third = third_table_offset(addr);
+ unsigned long ipa_second = second_table_offset(addr);
+ unsigned long ipa_first = first_table_offset(addr);
+
+ /* guest p2m's first level index is the index of xen's second level,
+ and guest p2m's second level index is the index of xen's third level */
+ return (lpae_t *)(
+ ( (second_linear_offset(VIRT_LIN_P2M_START) + ipa_first)
+ << SECOND_SHIFT) +
+ (ipa_second << THIRD_SHIFT) +
+ (ipa_third << 3) );
+}
+
#endif /* __ARCH_ARM_MM__ */
/*
* Local variables:
--
1.8.1.2
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |