[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH v6 1/7] xen/riscv: imsic_init() implementation
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.Caritey@xxxxxxxxxxxxx> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>Acked-by: Jan Beulich <jbeulich@xxxxxxxx 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
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