Hi Michal,
On 16/01/2023 14:41, Michal Orzel wrote:
The amount of supported physical memory depends on the frametable size
and the number of struct page_info entries that can fit into it. Define
a macro PAGE_INFO_SIZE to store the current size of the struct page_info
(i.e. 56B for arm64 and 32B for arm32) and add a sanity check in
setup_frametable_mappings to be notified whenever the size of the
structure changes. Also call a panic if the calculated frametable_size
exceeds the limit defined by FRAMETABLE_SIZE macro.
Update the comments regarding the frametable in asm/config.h and take
the opportunity to remove unused macro FRAMETABLE_VIRT_END on arm32.
Signed-off-by: Michal Orzel <michal.or...@amd.com>
---
xen/arch/arm/include/asm/config.h | 5 ++---
xen/arch/arm/include/asm/mm.h | 11 +++++++++++
xen/arch/arm/mm.c | 5 +++++
3 files changed, 18 insertions(+), 3 deletions(-)
diff --git a/xen/arch/arm/include/asm/config.h
b/xen/arch/arm/include/asm/config.h
index 16213c8b677f..d8f99776986f 100644
--- a/xen/arch/arm/include/asm/config.h
+++ b/xen/arch/arm/include/asm/config.h
@@ -82,7 +82,7 @@
* ARM32 layout:
* 0 - 12M <COMMON>
*
- * 32M - 128M Frametable: 24 bytes per page for 16GB of RAM
+ * 32M - 128M Frametable: 32 bytes per page for 12GB of RAM
* 256M - 1G VMAP: ioremap and early_ioremap use this virtual address
* space
*
@@ -95,7 +95,7 @@
*
* 1G - 2G VMAP: ioremap and early_ioremap
*
- * 32G - 64G Frametable: 24 bytes per page for 5.3TB of RAM
+ * 32G - 64G Frametable: 56 bytes per page for 2TB of RAM
*
* 0x0000008000000000 - 0x00007fffffffffff (127.5TB, L0 slots [1..255])
* Unused
@@ -127,7 +127,6 @@
#define FRAMETABLE_VIRT_START _AT(vaddr_t,0x02000000)
#define FRAMETABLE_SIZE MB(128-32)
#define FRAMETABLE_NR (FRAMETABLE_SIZE / sizeof(*frame_table))
-#define FRAMETABLE_VIRT_END (FRAMETABLE_VIRT_START + FRAMETABLE_SIZE - 1)
This is somewhat unrelated to the goal of the patch. We do clean-up in
the same patch, but they tend to be in the same of already modified hunk
(which is not the case here).
So I would prefer if this is split. This would make this patch a
potential candidate for backport.
#define VMAP_VIRT_START _AT(vaddr_t,0x10000000)
#define VMAP_VIRT_SIZE _AT(vaddr_t, GB(1) - MB(256))
diff --git a/xen/arch/arm/include/asm/mm.h b/xen/arch/arm/include/asm/mm.h
index 68adcac9fa8d..23dec574eb31 100644
--- a/xen/arch/arm/include/asm/mm.h
+++ b/xen/arch/arm/include/asm/mm.h
@@ -26,6 +26,17 @@
*/
#define PFN_ORDER(_pfn) ((_pfn)->v.free.order)
+/*
+ * The size of struct page_info impacts the number of entries that can fit
+ * into the frametable area and thus it affects the amount of physical memory
+ * we claim to support. Define PAGE_INFO_SIZE to be used for sanity checking.
+*/
+#ifdef CONFIG_ARM_64
+#define PAGE_INFO_SIZE 56
+#else
+#define PAGE_INFO_SIZE 32
+#endif
+
struct page_info
{
/* Each frame can be threaded onto a doubly-linked list. */
diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 0fc6f2992dd1..a8c28fa5b768 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -676,6 +676,11 @@ void __init setup_frametable_mappings(paddr_t ps, paddr_t
pe)
const unsigned long mapping_size = frametable_size < MB(32) ? MB(2) :
MB(32);
int rc;
+ BUILD_BUG_ON(sizeof(struct page_info) != PAGE_INFO_SIZE);
+
+ if ( frametable_size > FRAMETABLE_SIZE )
+ panic("RAM size is too big to fit in a frametable area\n");
This is not correct. Depending on the PDX compression, the frametable
may end up to cover non-RAM. So I would write:
"The cannot frametable cannot cover the physical region 0x%PRIpaddr -
0x%PRIpaddr".
+
frametable_base_pdx = mfn_to_pdx(maddr_to_mfn(ps));
/* Round up to 2M or 32M boundary, as appropriate. */
frametable_size = ROUNDUP(frametable_size, mapping_size);
Cheers,
--
Julien Grall
