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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Minios-devel] [UNIKRAFT PATCHv2 19/25] plat/kvm: arm64: Calculate pagetable size dynamically by image size
The previous L3 page table size is a fixed value based on the
assumption that, image size will not exceed 2MB. But that's not
true, some applications like node.js will be about 40MB after
converting to Unikernel. So in this patch, we calculate the
page table size by real image size. In order to mapping the
image occupied memory to L3 page table, we round up the image
size with 2MB. If we don't round up the image size with 2MB.
Some memory that is not occupied by image but shared the same
2MB block with image tail will be unmapped in page table.
Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
---
plat/common/include/sections.h | 31 +++++++++++++++++++++++++
plat/kvm/arm/entry64.S | 36 +++++++++++++++++++++++++++--
plat/kvm/arm/pagetable64.S | 4 +++-
plat/kvm/arm/setup.c | 2 +-
plat/kvm/include/kvm-arm/arm64/mm.h | 14 ++++++-----
5 files changed, 77 insertions(+), 10 deletions(-)
diff --git a/plat/common/include/sections.h b/plat/common/include/sections.h
index b32389c..5342e42 100644
--- a/plat/common/include/sections.h
+++ b/plat/common/include/sections.h
@@ -35,6 +35,7 @@
#ifndef __PLAT_CMN_SECTIONS_H__
#define __PLAT_CMN_SECTIONS_H__
+#ifndef __ASSEMBLY__
/*
* Following global variables are defined in image link scripts, and some
* variables are optional and may be unavailable on some architectures
@@ -94,4 +95,34 @@ extern char _end[];
#define __BSS_START __uk_image_symbol(__bss_start)
#define __END __uk_image_symbol(_end)
+#endif /*__ASSEMBLY__ */
+
+/*
+ * Because the section is 4KB alignment, and we will assign different
+ * attributes for different sections. We roundup image size to 2MB to
+ * avoid making holes in L3 table
+ *
+ * L2 table
+ * |-----------| L3 table
+ * | 2MB |===>|-----------|
+ * |-----------| | 4KB | entry#0
+ * |-----------|
+ * | ... |
+ * | |
+ * |-----------|
+ * | 4KB | entry# for last page of real image
+ * |-----------|
+ * | 4KB | entry# for round up memory
+ * |-----------|
+ * | ... |
+ * |-----------|
+ * | 4KB | entry#511
+ * |-----------|
+ * If we don't roundup the image size to 2MB, some memory that is not
+ * occupied by image but shared the same 2MB block with image tail will
+ * not be mapped in page table.
+ */
+#define IMAGE_ROUNDUP_SHIFT 20
+#define IMAGE_ROUNDUP_SIZE (0x1 << (IMAGE_ROUNDUP_SHIFT))
+
#endif /* __PLAT_CMN_SECTIONS_H__ */
diff --git a/plat/kvm/arm/entry64.S b/plat/kvm/arm/entry64.S
index d08b49e..867772f 100644
--- a/plat/kvm/arm/entry64.S
+++ b/plat/kvm/arm/entry64.S
@@ -35,6 +35,12 @@
#include <uk/asm.h>
#include <kvm-arm/mm.h>
#include <arm/cpu_defs.h>
+#include <sections.h>
+
+.global page_table_size
+.data
+page_table_size:
+ .dword 0x0
/*
* The registers used by _libkvmplat_start:
@@ -43,6 +49,29 @@
.text
ENTRY(_libkvmplat_entry)
+ /* Caculate the image size */
+ ldr x25, =_dtb
+ ldr x26, =_end
+ mov x15, x25
+ sub x15, x26, x15
+
+ /* Round up the size to 2MB */
+ mov x17, #(IMAGE_ROUNDUP_SIZE - 1)
+ add x15, x15, x17
+ lsr x15, x15, #IMAGE_ROUNDUP_SHIFT
+ lsl x15, x15, #IMAGE_ROUNDUP_SHIFT
+
+ /*
+ * How many bytes would be used for L3_TABLE
+ * ((x15 >> 21) << 12)
+ */
+ lsr x17, x15, #9
+
+ /* Total bytes for pagetable */
+ add x17, x17, #L0_TABLE_SIZE
+ add x17, x17, #L1_TABLE_SIZE
+ add x17, x17, #L2_TABLE_SIZE
+
/*
* Clean the boot stack and page table. As _end, PAGE_TABLE_SIZE and
@@ -50,8 +79,7 @@ ENTRY(_libkvmplat_entry)
* 64-bytes alignment too. Execute 4 stp consecutively without boundary
* check would be safe here.
*/
- ldr x26, =_end
- add x27, x26, #PAGE_TABLE_SIZE
+ add x27, x26, x17
add x27, x27, #__STACK_SIZE
1:
stp xzr, xzr, [x26], #16
@@ -79,6 +107,10 @@ ENTRY(_libkvmplat_entry)
/* Set the context id */
msr contextidr_el1, xzr
+ /* Save page table size for later usage */
+ ldr x26, =page_table_size
+ str x17, [x26]
+
/* Create a pagetable to do PA == VA mapping */
bl create_pagetables
diff --git a/plat/kvm/arm/pagetable64.S b/plat/kvm/arm/pagetable64.S
index a00b71c..bd473bf 100644
--- a/plat/kvm/arm/pagetable64.S
+++ b/plat/kvm/arm/pagetable64.S
@@ -233,7 +233,9 @@ ENTRY(start_mmu)
*/
ldr x0, =_data
ldr x1, =_end
- add x1, x1, #PAGE_TABLE_SIZE
+ ldr x2, =page_table_size
+ ldr x2, [x2]
+ add x1, x2, x1
add x1, x1, #__STACK_SIZE
sub x1, x1, x0
bl clean_and_invalidate_dcache_range
diff --git a/plat/kvm/arm/setup.c b/plat/kvm/arm/setup.c
index 5ffb629..7bd75bd 100644
--- a/plat/kvm/arm/setup.c
+++ b/plat/kvm/arm/setup.c
@@ -146,7 +146,7 @@ static void _init_dtb_mem(void)
max_addr = mem_base + mem_size;
_libkvmplat_pagetable =(void *) ALIGN_DOWN((size_t)__END, __PAGE_SIZE);
- _libkvmplat_heap_start = _libkvmplat_pagetable + PAGE_TABLE_SIZE;
+ _libkvmplat_heap_start = _libkvmplat_pagetable + page_table_size;
_libkvmplat_mem_end = (void *) max_addr;
/* AArch64 require stack be 16-bytes alignment by default */
diff --git a/plat/kvm/include/kvm-arm/arm64/mm.h
b/plat/kvm/include/kvm-arm/arm64/mm.h
index 23bc658..9ec1273 100644
--- a/plat/kvm/include/kvm-arm/arm64/mm.h
+++ b/plat/kvm/include/kvm-arm/arm64/mm.h
@@ -69,15 +69,17 @@
#define L2_TABLE_SIZE __PAGE_SIZE
/*
- * As Unikraft image's size is very tiny, from tens to hundreds kilo
- * bytes. So one page for L3_TABLE is enough for us to manage section
- * attributes of image.
+ * We will use Unikraft image's size to caculate the L3_TABLE_SIZE.
+ * Because we allocate one page for L2 TABLE, fo the max image size
+ * would be 1GB. It would be enough for current stage.
*/
#define L3_TABLE_OFFSET (L2_TABLE_OFFSET + L2_TABLE_SIZE)
-#define L3_TABLE_SIZE __PAGE_SIZE
+
+#ifndef __ASSEMBLY__
/* Total memory size that will be used by pagetable */
-#define PAGE_TABLE_SIZE (L0_TABLE_SIZE + L1_TABLE_SIZE + \
- L2_TABLE_SIZE + L3_TABLE_SIZE)
+extern uint64_t page_table_size;
+
+#endif /*__ASSEMBLY__ */
#endif /* __KVM_ARM_64_MM_H__ */
--
2.17.1
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