Hi,
On 20/06/2025 10:49, Hari Limaye wrote:
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From: Luca Fancellu <luca.fance...@arm.com>
Implement a function to find the index of a MPU region
in the xen_mpumap MPU region array.
Signed-off-by: Luca Fancellu <luca.fance...@arm.com>
Signed-off-by: Hari Limaye <hari.lim...@arm.com>
Reviewed-by: Ayan Kumar Halder <ayan.kumar.hal...@amd.com>
---
xen/arch/arm/include/asm/mpu/mm.h | 29 ++++++++++++++
xen/arch/arm/mpu/mm.c | 66 +++++++++++++++++++++++++++++++
2 files changed, 95 insertions(+)
diff --git a/xen/arch/arm/include/asm/mpu/mm.h
b/xen/arch/arm/include/asm/mpu/mm.h
index a7f970b465..a0f0d86d4a 100644
--- a/xen/arch/arm/include/asm/mpu/mm.h
+++ b/xen/arch/arm/include/asm/mpu/mm.h
@@ -10,6 +10,13 @@
#include <asm/mm.h>
#include <asm/mpu.h>
+#define MPUMAP_REGION_OVERLAP -1
+#define MPUMAP_REGION_NOTFOUND 0
+#define MPUMAP_REGION_FOUND 1
+#define MPUMAP_REGION_INCLUSIVE 2
+
+#define INVALID_REGION_IDX 0xFFU
+
extern struct page_info *frame_table;
extern uint8_t max_mpu_regions;
@@ -75,6 +82,28 @@ void write_protection_region(const pr_t *pr_write, uint8_t
sel);
*/
pr_t pr_of_addr(paddr_t base, paddr_t limit, unsigned int flags);
+/*
+ * Checks whether a given memory range is present in the provided table of
+ * MPU protection regions.
+ *
+ * @param table Array of pr_t protection regions.
+ * @param r_regions Number of elements in `table`.
+ * @param base Start of the memory region to be checked (inclusive).
+ * @param limit End of the memory region to be checked (exclusive).
+ * @param index Set to the index of the region if an exact or inclusive
+ * match is found, and INVALID_REGION otherwise.
+ * @return: Return code indicating the result of the search:
+ * MPUMAP_REGION_NOTFOUND: no part of the range is present in #table
+ * MPUMAP_REGION_FOUND: found an exact match in #table
+ * MPUMAP_REGION_INCLUSIVE: found an inclusive match in #table
+ * MPUMAP_REGION_OVERLAP: found an overlap with a mapping in #table
+ *
+ * Note: make sure that the range [#base, #limit) refers to the half-open
+ * interval inclusive of #base and exclusive of #limit.
+ */
+int mpumap_contain_region(pr_t *table, uint8_t nr_regions, paddr_t base,
+ paddr_t limit, uint8_t *index);
+
#endif /* __ARM_MPU_MM_H__ */
/*
diff --git a/xen/arch/arm/mpu/mm.c b/xen/arch/arm/mpu/mm.c
index ccfb37a67b..15197339b1 100644
--- a/xen/arch/arm/mpu/mm.c
+++ b/xen/arch/arm/mpu/mm.c
@@ -12,6 +12,18 @@
#include <asm/page.h>
#include <asm/sysregs.h>
+#ifdef NDEBUG
+static inline void __attribute__ ((__format__ (__printf__, 1, 2)))
+region_printk(const char *fmt, ...) {}
+#else /* !NDEBUG */
+#define region_printk(fmt, args...) \
+ do \
+ { \
+ dprintk(XENLOG_ERR, fmt, ## args); \
+ WARN(); \
+ } while (0)
+#endif /* NDEBUG */
+
struct page_info *frame_table;
/* Maximum number of supported MPU memory regions by the EL2 MPU. */
@@ -110,6 +122,60 @@ pr_t pr_of_addr(paddr_t base, paddr_t limit, unsigned int
flags)
return region;
}
+int mpumap_contain_region(pr_t *table, uint8_t nr_regions, paddr_t base,
+ paddr_t limit, uint8_t *index)
+{
+ uint8_t i = 0, _index;
+
+ /* Allow index to be NULL */
+ index = index ? index : &_index;
+
+ /* Inside mpumap_contain_region check for inclusive range */
+ limit = limit - 1;
+
+ *index = INVALID_REGION_IDX;
+
+ if ( limit < base )
+ {
+ region_printk("Base address 0x%"PRIpaddr" must be smaller than limit address
0x%"PRIpaddr"\n",
+ base, limit);
+ return -EINVAL;
+ }
+
+ for ( ; i < nr_regions; i++ )
+ {
+ paddr_t iter_base = pr_get_base(&table[i]);
+ paddr_t iter_limit = pr_get_limit(&table[i]);
+
+ /* Found an exact valid match */
+ if ( (iter_base == base) && (iter_limit == limit) &&
+ region_is_valid(&table[i]) )
+ {
+ *index = i;
+ return MPUMAP_REGION_FOUND;
+ }
+
+ /* No overlapping */
+ if ( (iter_limit < base) || (iter_base > limit) )
+ continue;
+
+ /* Inclusive and valid */
+ if ( (base >= iter_base) && (limit <= iter_limit) &&
+ region_is_valid(&table[i]) )
+ {
+ *index = i;
+ return MPUMAP_REGION_INCLUSIVE;
+ }
+
+ /* Overlap */
+ region_printk("Range 0x%"PRIpaddr" - 0x%"PRIpaddr" overlaps with the existing region
0x%"PRIpaddr" - 0x%"PRIpaddr"\n",
+ base, limit + 1, iter_base, iter_limit + 1);
+ return MPUMAP_REGION_OVERLAP;
+ }
+
+ return MPUMAP_REGION_NOTFOUND;
+}
+
void __init setup_mm(void)
{
BUG_ON("unimplemented");
LGTM.
- Ayan
--
2.34.1
