[PATCH v5 3/9] lib: fdt_domain: parse domain WID properties
Yu-Chien Peter Lin
peter.lin at sifive.com
Tue Nov 10 01:50:23 PST 2026
Add wid and widdeleg fields to struct sbi_domain to store the
RISC-V Worlds mlwid and mwiddeleg CSR values for each domain.
Also, parse the root and user-defined domains' WID during
fdt_domains_populate().
The root domain WID is described in the "root" subnode, which
carries the "opensbi,domain,instance" compatible string. Skip
this node in fdt_iterate_each_domain() so that it is not
treated as a regular domain instance.
When Smlwid is implemented, the "wid" property is mandatory
for all domains; fail domain population if it is missing.
Signed-off-by: Yu-Chien Peter Lin <peter.lin at sifive.com>
---
Changes v4->v5:
- Reject wid >= XLEN and, on RV32, widdeleg wider than MXLEN, so
BIT_ULL(dom->wid) is safe (Radim)
- Drop RB-tag from Anup
---
include/sbi/sbi_domain.h | 6 +++
lib/sbi/sbi_domain.c | 2 +
lib/utils/fdt/fdt_domain.c | 102 +++++++++++++++++++++++++++++++++++++
3 files changed, 110 insertions(+)
diff --git a/include/sbi/sbi_domain.h b/include/sbi/sbi_domain.h
index 56a21397..5a291d1f 100644
--- a/include/sbi/sbi_domain.h
+++ b/include/sbi/sbi_domain.h
@@ -19,6 +19,8 @@
struct sbi_scratch;
+#define INVALID_WID ((unsigned int)~0U)
+
/** Domain access types */
enum sbi_domain_access {
SBI_DOMAIN_READ = (1UL << 0),
@@ -218,6 +220,10 @@ struct sbi_domain {
bool system_reset_allowed;
/** Is domain allowed to suspend the system */
bool system_suspend_allowed;
+ /** World ID for this domain (mlwid value) */
+ u32 wid;
+ /** World ID delegation bitmask for this domain (mwiddeleg value) */
+ u64 widdeleg;
/** Identifies whether to include the firmware region */
bool fw_region_inited;
};
diff --git a/lib/sbi/sbi_domain.c b/lib/sbi/sbi_domain.c
index 42fe5632..be9020d0 100644
--- a/lib/sbi/sbi_domain.c
+++ b/lib/sbi/sbi_domain.c
@@ -30,6 +30,8 @@ struct sbi_domain root = {
.possible_harts = NULL,
.system_reset_allowed = true,
.system_suspend_allowed = true,
+ .wid = INVALID_WID,
+ .widdeleg = 0,
.fw_region_inited = false,
};
diff --git a/lib/utils/fdt/fdt_domain.c b/lib/utils/fdt/fdt_domain.c
index e4cce8c3..295587b0 100644
--- a/lib/utils/fdt/fdt_domain.c
+++ b/lib/utils/fdt/fdt_domain.c
@@ -13,6 +13,7 @@
#include <sbi/sbi_console.h>
#include <sbi/sbi_domain.h>
#include <sbi/sbi_error.h>
+#include <sbi/sbi_hart.h>
#include <sbi/sbi_hartmask.h>
#include <sbi/sbi_heap.h>
#include <sbi/sbi_scratch.h>
@@ -37,6 +38,9 @@ int fdt_iterate_each_domain(void *fdt, void *opaque,
return 0;
fdt_for_each_subnode(doffset, fdt, poffset) {
+ if (!strcmp(fdt_get_name(fdt, doffset, NULL), "root"))
+ continue;
+
if (fdt_node_check_compatible(fdt, doffset,
"opensbi,domain,instance"))
continue;
@@ -290,6 +294,57 @@ static int __fdt_parse_region(const void *fdt, int domain_offset,
return 0;
}
+static void fdt_parse_domain_wid_props(const void *fdt, int offset,
+ struct sbi_domain *dom)
+{
+ const fdt32_t *val;
+ int len;
+ u64 val64;
+
+ val = fdt_getprop(fdt, offset, "wid", &len);
+ if (val && len == sizeof(fdt32_t))
+ dom->wid = fdt32_to_cpu(val[0]);
+
+ val = fdt_getprop(fdt, offset, "widdeleg", &len);
+ if (val && (len == (2 * sizeof(fdt32_t)))) {
+ val64 = fdt32_to_cpu(val[0]);
+ val64 = (val64 << 32) | fdt32_to_cpu(val[1]);
+ dom->widdeleg = val64;
+ }
+}
+
+static int validate_domain_wid(const struct sbi_domain *dom)
+{
+ /* Worlds supports at most XLEN WIDs, and mwiddeleg is MXLEN bits */
+ if (dom->wid != INVALID_WID && dom->wid >= __riscv_xlen) {
+ sbi_printf("%s: domain \"%s\": \"wid\" %u exceeds max WID %u\n",
+ __func__, dom->name, dom->wid, __riscv_xlen - 1);
+ return SBI_EINVAL;
+ }
+
+#if __riscv_xlen == 32
+ if (dom->widdeleg >> 32) {
+ sbi_printf("%s: domain \"%s\": \"widdeleg\" 0x%llx exceeds MXLEN\n",
+ __func__, dom->name,
+ (unsigned long long)dom->widdeleg);
+ return SBI_EINVAL;
+ }
+#endif
+
+ if (dom->wid != INVALID_WID)
+ return 0;
+
+ if (sbi_hart_has_extension(sbi_scratch_thishart_ptr(),
+ SBI_HART_EXT_SMLWID)) {
+ sbi_printf("%s: domain \"%s\": missing \"wid\""
+ " property (required by Smlwid)\n",
+ __func__, dom->name);
+ return SBI_EINVAL;
+ }
+
+ return 0;
+}
+
static int __fdt_parse_domain(const void *fdt, int domain_offset, void *opaque)
{
u32 val32;
@@ -306,6 +361,7 @@ static int __fdt_parse_domain(const void *fdt, int domain_offset, void *opaque)
dom = sbi_zalloc(sizeof(*dom));
if (!dom)
return SBI_ENOMEM;
+ dom->wid = INVALID_WID;
preg.dom = dom;
preg.region_count = 0;
@@ -449,6 +505,12 @@ static int __fdt_parse_domain(const void *fdt, int domain_offset, void *opaque)
}
dom->next_mode = val32;
+ /* Read "wid" and "widdeleg" DT properties */
+ fdt_parse_domain_wid_props(fdt, domain_offset, dom);
+ err = validate_domain_wid(dom);
+ if (err)
+ goto fail_free_all;
+
/* Read "system-reset-allowed" DT property */
if (fdt_get_property(fdt, domain_offset,
"system-reset-allowed", NULL))
@@ -477,12 +539,52 @@ fail_free_domain:
return err;
}
+static int fdt_root_domain_offset(const void *fdt)
+{
+ int offset;
+
+ offset = fdt_path_offset(fdt, "/chosen");
+ if (offset < 0)
+ return offset;
+
+ offset = fdt_node_offset_by_compatible(fdt, offset,
+ "opensbi,domain,config");
+ if (offset < 0)
+ return offset;
+
+ return fdt_subnode_offset(fdt, offset, "root");
+}
+
+static int fdt_parse_root_domain(const void *fdt)
+{
+ int offset;
+
+ if (fdt) {
+ offset = fdt_root_domain_offset(fdt);
+ if (offset >= 0)
+ fdt_parse_domain_wid_props(fdt, offset, &root);
+ }
+
+ /*
+ * Ensure root domain has a valid WID
+ * even if FDT or root subnode is absent
+ */
+ return validate_domain_wid(&root);
+}
+
int fdt_domains_populate(const void *fdt)
{
+ int err;
+
/* Sanity checks */
if (!fdt)
return SBI_EINVAL;
+ /* Parse root domain config from "root" subnode */
+ err = fdt_parse_root_domain(fdt);
+ if (err)
+ return err;
+
/* Iterate over each domain in FDT and populate details */
return fdt_iterate_each_domain_ro(fdt, NULL, __fdt_parse_domain);
}
--
2.43.7
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