@@ -209,12 +209,19 @@ static void acpi_dsdt_add_tpm(Aml *scope, VirtMachineState *vms)
#define ROOT_COMPLEX_ENTRY_SIZE 36
#define IORT_NODE_OFFSET 48
+/*
+ * Append an ID mapping entry as described by "Table 4 ID mapping format" in
+ * "IO Remapping Table System Software on ARM Platforms", Chapter 3.
+ * Document number: ARM DEN 0049E.f, Apr 2024
+ *
+ * Note that @id_count gets internally subtracted by one, following the spec.
+ */
static void build_iort_id_mapping(GArray *table_data, uint32_t input_base,
uint32_t id_count, uint32_t out_ref)
{
- /* Table 4 ID mapping format */
build_append_int_noprefix(table_data, input_base, 4); /* Input base */
- build_append_int_noprefix(table_data, id_count, 4); /* Number of IDs */
+ /* Number of IDs - The number of IDs in the range minus one */
+ build_append_int_noprefix(table_data, id_count - 1, 4);
build_append_int_noprefix(table_data, input_base, 4); /* Output base */
build_append_int_noprefix(table_data, out_ref, 4); /* Output Reference */
/* Flags */
@@ -306,8 +313,8 @@ build_iort(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
}
/* Append the last RC -> ITS ID mapping */
- if (next_range.input_base < 0xFFFF) {
- next_range.id_count = 0xFFFF - next_range.input_base;
+ if (next_range.input_base < 0x10000) {
+ next_range.id_count = 0x10000 - next_range.input_base;
g_array_append_val(its_idmaps, next_range);
}
@@ -366,7 +373,7 @@ build_iort(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
build_append_int_noprefix(table_data, 0, 4);
/* output IORT node is the ITS group node (the first node) */
- build_iort_id_mapping(table_data, 0, 0xFFFF, IORT_NODE_OFFSET);
+ build_iort_id_mapping(table_data, 0, 0x10000, IORT_NODE_OFFSET);
}
/* Table 17 Root Complex Node */
@@ -419,7 +426,7 @@ build_iort(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
}
} else {
/* output IORT node is the ITS group node (the first node) */
- build_iort_id_mapping(table_data, 0, 0xFFFF, IORT_NODE_OFFSET);
+ build_iort_id_mapping(table_data, 0, 0x10000, IORT_NODE_OFFSET);
}
acpi_table_end(linker, &table);
It's observed that Linux kernel booting with the VM reports a "conflicting mapping for input ID" FW_BUG. The IORT doc defines "Number of IDs" to be "the number of IDs in the range minus one", while virt-acpi-build.c simply stores the number of IDs in the id_count without the "minus one". Meanwhile, some of the callers pass in a 0xFFFF following the spec. So, this is a mismatch between the function and its callers. Fix build_iort_id_mapping() by internally subtracting one from the pass-in @id_count. Accordingly make sure that all existing callers pass in a value without the "minus one", i.e. change all 0xFFFFs to 0x10000s. Also, add a few lines of comments to highlight this change along with the referencing document for this build_iort_id_mapping(). Fixes: 42e0f050e3a5 ("hw/arm/virt-acpi-build: Add IORT support to bypass SMMUv3") Suggested-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com> --- Changelog v4: * Rephrased the function documentation and used the latest IORT spec ver. * Added "Reviewed-by" from Eric v3: https://lore.kernel.org/all/20240618211110.922809-1-nicolinc@nvidia.com/ * Added "-1" internally in build_iort_id_mapping() instead * Added comments to highlight this and referencing doc v2: https://lore.kernel.org/all/20240617223945.906996-1-nicolinc@nvidia.com/ * Moved "-1" to the same line of id_count calculation * Added "+1" to the next_range.input_base calculation v1: https://lore.kernel.org/all/20240613234802.828265-1-nicolinc@nvidia.com/ hw/arm/virt-acpi-build.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-)