The sbsa-ref machine is continuously evolving. Some of the changes we
want to make in the near future, to align with real components (e.g.
the GIC-700), will break compatibility for existing firmware.
Introduce two new properties to the DT generated on machine generation:
- machine-version-major
To be incremented when a platform change makes the machine
incompatible with existing firmware.
- machine-version-minor
To be incremented when functionality is added to the machine
without causing incompatibility with existing firmware.
to be reset to 0 when machine-version-major is incremented.
This versioning scheme is *neither*:
- A QEMU versioned machine type; a given version of QEMU will emulate
a given version of the platform.
- A reflection of level of SBSA (now SystemReady SR) support provided.
The version will increment on guest-visible functional changes only,
akin to a revision ID register found on a physical platform.
These properties are both introduced with the value 0.
(Hence, a machine where the DT is lacking these nodes is equivalent
to version 0.0.)
Signed-off-by: Leif Lindholm <quic_llind...@quicinc.com>
Cc: Peter Maydell <peter.mayd...@linaro.org>
Cc: Radoslaw Biernacki <r...@semihalf.com>
Cc: Cédric Le Goater <c...@kaod.org>
---
Changes since v1:
- More detail added to commit message.
- Verbose comment added adjacent to code additions.
hw/arm/sbsa-ref.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/hw/arm/sbsa-ref.c b/hw/arm/sbsa-ref.c
index 2387401963..d0c25ddfcf 100644
--- a/hw/arm/sbsa-ref.c
+++ b/hw/arm/sbsa-ref.c
@@ -190,6 +190,20 @@ static void create_fdt(SBSAMachineState *sms)
qemu_fdt_setprop_cell(fdt, "/", "#address-cells", 0x2);
qemu_fdt_setprop_cell(fdt, "/", "#size-cells", 0x2);
+ /*
+ * This versioning scheme is for informing platform fw only. It is neither:
+ * - A QEMU versioned machine type; a given version of QEMU will emulate
+ * a given version of the platform.
+ * - A reflection of level of SBSA (now SystemReady SR) support provided.
+ *
+ * machine-version-major: updated when changes breaking fw compatibility
+ * are introduced.
+ * machine-version-minor: updated when features are added that don't break
+ * fw compatibility.
+ */
+ qemu_fdt_setprop_cell(fdt, "/", "machine-version-major", 0);
+ qemu_fdt_setprop_cell(fdt, "/", "machine-version-minor", 0);
+
if (ms->numa_state->have_numa_distance) {
int size = nb_numa_nodes * nb_numa_nodes * 3 * sizeof(uint32_t);
uint32_t *matrix = g_malloc0(size);
--
2.30.2
