On 7/8/25 3:52 PM, Jan Beulich wrote:
On 07.07.2025 11:01, Oleksii Kurochko wrote:
imsic_init() is introduced to parse device tree node, which has the following
bindings [2], and based on the parsed information update IMSIC configuration
which is stored in imsic_cfg.
The following helpers are introduces for imsic_init() usage:
- imsic_parse_node() parses IMSIC node from DTS
- imsic_get_parent_hartid() returns the hart ( CPU ) ID of the given device
tree node.
This patch is based on the code from [1].
Since Microchip originally developed imsic.{c,h}, an internal discussion with
them led to the decision to use the MIT license.
[1]https://gitlab.com/xen-project/people/olkur/xen/-/commit/0b1a94f2bc3bb1a81cd26bb75f0bf578f84cb4d4
[2]https://elixir.bootlin.com/linux/v6.12/source/Documentation/devicetree/bindings/interrupt-controller/riscv,imsics.yaml
Co-developed-by: Romain Caritey<romain.cari...@microchip.com>
Signed-off-by: Oleksii Kurochko<oleksii.kuroc...@gmail.com>
Acked-by: Jan Beulich <jbeul...@suse.com
I'm curious though:
--- a/xen/arch/riscv/include/asm/smp.h
+++ b/xen/arch/riscv/include/asm/smp.h
@@ -3,6 +3,7 @@
#define ASM__RISCV__SMP_H
#include <xen/cpumask.h>
+#include <xen/macros.h>
#include <xen/percpu.h>
#include <asm/current.h>
@@ -18,6 +19,18 @@ static inline unsigned long cpuid_to_hartid(unsigned long
cpuid)
return pcpu_info[cpuid].hart_id;
}
+static inline unsigned int hartid_to_cpuid(unsigned long hartid)
+{
+ for ( unsigned int cpu = 0; cpu < ARRAY_SIZE(pcpu_info); cpu++ )
+ {
+ if ( hartid == cpuid_to_hartid(cpu) )
+ return cpu;
+ }
+
+ /* hartid isn't valid for some reason */
+ return NR_CPUS;
+}
Since there's no FIXME or alike here, is this really intended to remain this
way? With many CPUs this form of lookup can be pretty inefficient.
In the case with a big amount of CPUs it will require to update it. I will
create
TODO task in my repo to not forget to update it in a future.
Thanks.
~ Oleksii
