From: Julien Grall <jgr...@amazon.com>
At the moment, *_VIRT_END may either point to the address after the end
or the last address of the region.
The lack of consistency make quite difficult to reason with them.
Furthermore, there is a risk of overflow in the case where the address
points past to the end. I am not aware of any cases, so this is only a
latent bug.
Start to solve the problem by removing all the *_VIRT_END exclusively used
by the Arm code and add *_VIRT_SIZE when it is not present.
Take the opportunity to rename BOOT_FDT_SLOT_SIZE to BOOT_FDT_VIRT_SIZE
for better consistency and use _AT(vaddr_t, ).
Also take the opportunity to fix the coding style of the comment touched
in mm.c.
Signed-off-by: Julien Grall <jgr...@amazon.com>
----
I noticed that a few functions in Xen expect [start, end[. This is risky
as we may end up with end < start if the region is defined right at the
top of the address space.
I haven't yet tackle this issue. But I would at least like to get rid
of *_VIRT_END.
This was originally sent separately (lets call it v0).
Changes in v1:
- Mention the coding style change.
---
xen/arch/arm/include/asm/config.h | 18 ++++++++----------
xen/arch/arm/livepatch.c | 2 +-
xen/arch/arm/mm.c | 13 ++++++++-----
3 files changed, 17 insertions(+), 16 deletions(-)
diff --git a/xen/arch/arm/include/asm/config.h
b/xen/arch/arm/include/asm/config.h
index 3e2a55a91058..66db618b34e7 100644
--- a/xen/arch/arm/include/asm/config.h
+++ b/xen/arch/arm/include/asm/config.h
@@ -111,12 +111,11 @@
#define FIXMAP_ADDR(n) (_AT(vaddr_t,0x00400000) + (n) * PAGE_SIZE)
#define BOOT_FDT_VIRT_START _AT(vaddr_t,0x00600000)
-#define BOOT_FDT_SLOT_SIZE MB(4)
-#define BOOT_FDT_VIRT_END (BOOT_FDT_VIRT_START + BOOT_FDT_SLOT_SIZE)
+#define BOOT_FDT_VIRT_SIZE _AT(vaddr_t, MB(4))
#ifdef CONFIG_LIVEPATCH
#define LIVEPATCH_VMAP_START _AT(vaddr_t,0x00a00000)
-#define LIVEPATCH_VMAP_END (LIVEPATCH_VMAP_START + MB(2))
+#define LIVEPATCH_VMAP_SIZE _AT(vaddr_t, MB(2))
#endif
#define HYPERVISOR_VIRT_START XEN_VIRT_START
@@ -132,18 +131,18 @@
#define FRAMETABLE_VIRT_END (FRAMETABLE_VIRT_START + FRAMETABLE_SIZE - 1)
#define VMAP_VIRT_START _AT(vaddr_t,0x10000000)
+#define VMAP_VIRT_SIZE _AT(vaddr_t, GB(1) - MB(256))
#define XENHEAP_VIRT_START _AT(vaddr_t,0x40000000)
-#define XENHEAP_VIRT_END _AT(vaddr_t,0x7fffffff)
-#define DOMHEAP_VIRT_START _AT(vaddr_t,0x80000000)
-#define DOMHEAP_VIRT_END _AT(vaddr_t,0xffffffff)
+#define XENHEAP_VIRT_SIZE _AT(vaddr_t, GB(1))
-#define VMAP_VIRT_END XENHEAP_VIRT_START
+#define DOMHEAP_VIRT_START _AT(vaddr_t,0x80000000)
+#define DOMHEAP_VIRT_SIZE _AT(vaddr_t, GB(2))
#define DOMHEAP_ENTRIES 1024 /* 1024 2MB mapping slots */
/* Number of domheap pagetable pages required at the second level (2MB
mappings) */
-#define DOMHEAP_SECOND_PAGES ((DOMHEAP_VIRT_END - DOMHEAP_VIRT_START + 1) >>
FIRST_SHIFT)
+#define DOMHEAP_SECOND_PAGES (DOMHEAP_VIRT_SIZE >> FIRST_SHIFT)
#else /* ARM_64 */
@@ -152,12 +151,11 @@
#define SLOT0_ENTRY_SIZE SLOT0(1)
#define VMAP_VIRT_START GB(1)
-#define VMAP_VIRT_END (VMAP_VIRT_START + GB(1))
+#define VMAP_VIRT_SIZE GB(1)
#define FRAMETABLE_VIRT_START GB(32)
#define FRAMETABLE_SIZE GB(32)
#define FRAMETABLE_NR (FRAMETABLE_SIZE / sizeof(*frame_table))
-#define FRAMETABLE_VIRT_END (FRAMETABLE_VIRT_START + FRAMETABLE_SIZE - 1)
#define DIRECTMAP_VIRT_START SLOT0(256)
#define DIRECTMAP_SIZE (SLOT0_ENTRY_SIZE * (265-256))
diff --git a/xen/arch/arm/livepatch.c b/xen/arch/arm/livepatch.c
index 75e8adcfd6a1..57abc746e60b 100644
--- a/xen/arch/arm/livepatch.c
+++ b/xen/arch/arm/livepatch.c
@@ -175,7 +175,7 @@ void __init arch_livepatch_init(void)
void *start, *end;
start = (void *)LIVEPATCH_VMAP_START;
- end = (void *)LIVEPATCH_VMAP_END;
+ end = start + LIVEPATCH_VMAP_SIZE;
vm_init_type(VMAP_XEN, start, end);
diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index be37176a4725..0607c65f95cd 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -128,9 +128,11 @@ static DEFINE_PAGE_TABLE(xen_first);
/* xen_pgtable == root of the trie (zeroeth level on 64-bit, first on 32-bit)
*/
static DEFINE_PER_CPU(lpae_t *, xen_pgtable);
#define THIS_CPU_PGTABLE this_cpu(xen_pgtable)
-/* xen_dommap == pages used by map_domain_page, these pages contain
+/*
+ * xen_dommap == pages used by map_domain_page, these pages contain
* the second level pagetables which map the domheap region
- * DOMHEAP_VIRT_START...DOMHEAP_VIRT_END in 2MB chunks. */
+ * starting at DOMHEAP_VIRT_START in 2MB chunks.
+ */
static DEFINE_PER_CPU(lpae_t *, xen_dommap);
/* Root of the trie for cpu0, other CPU's PTs are dynamically allocated */
static DEFINE_PAGE_TABLE(cpu0_pgtable);
@@ -476,7 +478,7 @@ mfn_t domain_page_map_to_mfn(const void *ptr)
int slot = (va - DOMHEAP_VIRT_START) >> SECOND_SHIFT;
unsigned long offset = (va>>THIRD_SHIFT) & XEN_PT_LPAE_ENTRY_MASK;
- if ( va >= VMAP_VIRT_START && va < VMAP_VIRT_END )
+ if ( (va >= VMAP_VIRT_START) && ((VMAP_VIRT_START - va) < VMAP_VIRT_SIZE) )
return virt_to_mfn(va);
ASSERT(slot >= 0 && slot < DOMHEAP_ENTRIES);
@@ -570,7 +572,8 @@ void __init remove_early_mappings(void)
int rc;
/* destroy the _PAGE_BLOCK mapping */
- rc = modify_xen_mappings(BOOT_FDT_VIRT_START, BOOT_FDT_VIRT_END,
+ rc = modify_xen_mappings(BOOT_FDT_VIRT_START,
+ BOOT_FDT_VIRT_START + BOOT_FDT_VIRT_SIZE,
_PAGE_BLOCK);
BUG_ON(rc);
}
@@ -850,7 +853,7 @@ void __init setup_frametable_mappings(paddr_t ps, paddr_t
pe)
void *__init arch_vmap_virt_end(void)
{
- return (void *)VMAP_VIRT_END;
+ return (void *)(VMAP_VIRT_START + VMAP_VIRT_SIZE);
}
/*
--
2.32.0
