On 4/10/25 10:48 AM, Jan Beulich wrote:
On 09.04.2025 21:01, Oleksii Kurochko wrote:
--- a/xen/arch/riscv/include/asm/mm.h
+++ b/xen/arch/riscv/include/asm/mm.h
@@ -9,6 +9,7 @@
#include <xen/mm-frame.h>
#include <xen/pdx.h>
#include <xen/pfn.h>
+#include <xen/sections.h>
#include <xen/types.h>
#include <asm/page-bits.h>
@@ -35,6 +36,11 @@ static inline void *maddr_to_virt(paddr_t ma)
return (void *)va;
}
+#define is_init_section(p) ({ \
+ char *p_ = (char *)(unsigned long)(p); \
+ (p_ >= __init_begin) && (p_ < __init_end); \
+})
I think this wants to be put in xen/sections.h, next to where __init_{begin,end}
are declared. But first it wants making const-correct, to eliminate the
potential
of it indirectly casting away const-ness from the incoming argument.
(At some point related stuff wants moving from kernel.h to sections.h, I
suppose.
And at that point they will all want to have const added.)
Sure, I'll change to 'const char *p_ = (const char*)(unsigned long)(p)'.
--- a/xen/arch/riscv/mm.c
+++ b/xen/arch/riscv/mm.c
@@ -31,20 +31,24 @@ unsigned long __ro_after_init phys_offset; /* = load_start
- XEN_VIRT_START */
#define LOAD_TO_LINK(addr) ((unsigned long)(addr) - phys_offset)
/*
- * It is expected that Xen won't be more then 2 MB.
+ * It is expected that Xen won't be more then XEN_VIRT_SIZE MB.
Why "MB" when the macro already expands to MB(16)?
It should be really dropped, no need for MB in the comment.
* The check in xen.lds.S guarantees that.
- * At least 3 page tables (in case of Sv39 ) are needed to cover 2 MB.
- * One for each page level table with PAGE_SIZE = 4 Kb.
*
- * One L0 page table can cover 2 MB(512 entries of one page table * PAGE_SIZE).
+ * Root page table is shared with the initial mapping and is declared
+ * separetely. (look at stage1_pgtbl_root)
Nit: separately
*
- * It might be needed one more page table in case when Xen load address
- * isn't 2 MB aligned.
+ * An amount of page tables between root page table and L0 page table
+ * (in the case of Sv39 it covers L1 table):
+ * (CONFIG_PAGING_LEVELS - 2) are needed for an identity mapping and
+ * the same amount are needed for Xen.
*
- * CONFIG_PAGING_LEVELS page tables are needed for the identity mapping,
- * except that the root page table is shared with the initial mapping
+ * An amount of L0 page tables:
+ * (512 entries of one L0 page table covers 2MB == 1<<XEN_PT_LEVEL_SHIFT(1))
+ * XEN_VIRT_SIZE >> XEN_PT_LEVEL_SHIFT(1) are needed for Xen and
+ * one L0 is needed for indenity mapping.
Nit: identity
But more importantly, where's this one L0 ...
*/
-#define PGTBL_INITIAL_COUNT ((CONFIG_PAGING_LEVELS - 1) * 2 + 1)
+#define PGTBL_INITIAL_COUNT ((CONFIG_PAGING_LEVELS - 2) * 2 + \
+ (XEN_VIRT_SIZE >> XEN_PT_LEVEL_SHIFT(1)))
.... in this calculation?
L0 for identity mapping is really missed.
Thanks.
~ Oleksii
