Implement the mfn_valid() macro to verify whether a given MFN is valid by
checking that it falls within the range [start_page, max_page).
These bounds are initialized based on the start and end addresses of RAM.
As part of this patch, start_page is introduced and initialized with the
PFN of the first RAM page.
Also, initialize pdx_group_valid() by calling set_pdx_range() when
memory banks are being mapped.
Also, after providing a non-stub implementation of the mfn_valid() macro,
the following compilation errors started to occur:
riscv64-linux-gnu-ld: prelink.o: in function `__next_node':
/build/xen/./include/xen/nodemask.h:202: undefined reference to
`page_is_ram_type'
riscv64-linux-gnu-ld: prelink.o: in function `get_free_buddy':
/build/xen/common/page_alloc.c:881: undefined reference to `page_is_ram_type'
riscv64-linux-gnu-ld: prelink.o: in function `alloc_heap_pages':
/build/xen/common/page_alloc.c:1043: undefined reference to
`page_get_owner_and_reference'
riscv64-linux-gnu-ld: /build/xen/common/page_alloc.c:1098: undefined
reference to `page_is_ram_type'
riscv64-linux-gnu-ld: prelink.o: in function `ns16550_interrupt':
/build/xen/drivers/char/ns16550.c:205: undefined reference to `get_page'
riscv64-linux-gnu-ld: ./.xen-syms.0: hidden symbol
`page_get_owner_and_reference' isn't defined
riscv64-linux-gnu-ld: final link failed: bad value
make[2]: *** [arch/riscv/Makefile:35: xen-syms] Error 1
To resolve these errors, the following functions have also been introduced,
based on their Arm counterparts:
- page_get_owner_and_reference() and its variant to safely acquire a
reference to a page and retrieve its owner.
- A stub for page_is_ram_type() that currently always returns 0 and asserts
unreachable, as RAM type checking is not yet implemented.
Signed-off-by: Oleksii Kurochko <oleksii.kuroc...@gmail.com>
---
Changes in V3:
- Update defintion of mfn_valid().
- Use __ro_after_init for variable start_page.
- Drop ASSERT_UNREACHABLE() in page_get_owner_and_nr_reference().
- Update the comment inside do/while in page_get_owner_and_nr_reference().
- Define _PGC_static and drop "#ifdef CONFIG_STATIC_MEMORY" in put_page_nr().
- Initialize pdx_group_valid() by calling set_pdx_range() when memory banks
are mapped.
- Drop page_get_owner_and_nr_reference() and implement
page_get_owner_and_reference()
without reusing of a page_get_owner_and_nr_reference() to avoid potential
dead code.
- Move defintion of get_page() to "xen/riscv: add support of page lookup by
GFN", where
it is really used.
---
Changes in V2:
- New patch.
---
xen/arch/riscv/include/asm/mm.h | 9 +++++++--
xen/arch/riscv/mm.c | 35 +++++++++++++++++++++++++++++++++
2 files changed, 42 insertions(+), 2 deletions(-)
diff --git a/xen/arch/riscv/include/asm/mm.h b/xen/arch/riscv/include/asm/mm.h
index b914813e52..d5be328906 100644
--- a/xen/arch/riscv/include/asm/mm.h
+++ b/xen/arch/riscv/include/asm/mm.h
@@ -5,6 +5,7 @@
#include <public/xen.h>
#include <xen/bug.h>
+#include <xen/compiler.h>
#include <xen/const.h>
#include <xen/mm-frame.h>
#include <xen/pdx.h>
@@ -309,8 +310,12 @@ static inline bool arch_mfns_in_directmap(unsigned long
mfn, unsigned long nr)
#define page_get_owner(p) (p)->v.inuse.domain
#define page_set_owner(p, d) ((p)->v.inuse.domain = (d))
-/* TODO: implement */
-#define mfn_valid(mfn) ({ (void)(mfn); 0; })
+extern unsigned long start_page;
+
+#define mfn_valid(mfn) ({ \
+ unsigned long mfn__ = mfn_x(mfn); \
+ likely((mfn__ >= start_page)) && likely(__mfn_valid(mfn__)); \
+})
#define domain_set_alloc_bitsize(d) ((void)(d))
#define domain_clamp_alloc_bitsize(d, b) ((void)(d), (b))
diff --git a/xen/arch/riscv/mm.c b/xen/arch/riscv/mm.c
index 3cac16f1b7..3ad2b9cf93 100644
--- a/xen/arch/riscv/mm.c
+++ b/xen/arch/riscv/mm.c
@@ -521,6 +521,8 @@ static void __init setup_directmap_mappings(unsigned long
base_mfn,
#error setup_{directmap,frametable}_mapping() should be implemented for RV_32
#endif
+unsigned long __ro_after_init start_page;
+
/*
* Setup memory management
*
@@ -570,9 +572,13 @@ void __init setup_mm(void)
ram_end = max(ram_end, bank_end);
setup_directmap_mappings(PFN_DOWN(bank_start), PFN_DOWN(bank_size));
+
+ set_pdx_range(paddr_to_pfn(bank_start), paddr_to_pfn(bank_end));
}
setup_frametable_mappings(ram_start, ram_end);
+
+ start_page = PFN_DOWN(ram_start);
max_page = PFN_DOWN(ram_end);
}
@@ -642,3 +648,32 @@ void put_page(struct page_info *page)
free_domheap_page(page);
}
}
+
+int page_is_ram_type(unsigned long mfn, unsigned long mem_type)
+{
+ ASSERT_UNREACHABLE();
+
+ return 0;
+}
+
+struct domain *page_get_owner_and_reference(struct page_info *page)
+{
+ unsigned long x, y = page->count_info;
+ struct domain *owner;
+
+ do {
+ x = y;
+ /*
+ * Count == 0: Page is not allocated, so we cannot take a reference.
+ * Count == -1: Reference count would wrap, which is invalid.
+ */
+ if ( unlikely(((x + 1) & PGC_count_mask) <= 1) )
+ return NULL;
+ }
+ while ( (y = cmpxchg(&page->count_info, x, x + 1)) != x );
+
+ owner = page_get_owner(page);
+ ASSERT(owner);
+
+ return owner;
+}
--
2.50.1
