Hi Michal,
On 5/21/2024 3:47 PM, Michal Orzel wrote:
Hi Henry.
On 3/21/2024 11:57 AM, Henry Wang wrote:
In the common sysctl command XEN_SYSCTL_physinfo, the value of
cores_per_socket is calculated based on the cpu_core_mask of CPU0.
Currently on Arm this is a fixed value 1 (can be checked via xl info),
which is not correct. This is because during the Arm CPU online
process at boot time, setup_cpu_sibling_map() only sets the per-cpu
cpu_core_mask for itself.
cores_per_socket refers to the number of cores that belong to the same
socket (NUMA node). Currently Xen on Arm does not support physical
CPU hotplug and NUMA, also we assume there is no multithread. Therefore
cores_per_socket means all possible CPUs detected from the device
tree. Setting the per-cpu cpu_core_mask in setup_cpu_sibling_map()
accordingly. Modify the in-code comment which seems to be outdated. Add
a warning to users if Xen is running on processors with multithread
support.
Signed-off-by: Henry Wang <henry.w...@arm.com>
Signed-off-by: Henry Wang <xin.wa...@amd.com>
Reviewed-by: Michal Orzel <michal.or...@amd.com>
Thanks.
/* ID of the PCPU we're running on */
DEFINE_PER_CPU(unsigned int, cpu_id);
-/* XXX these seem awfully x86ish... */
+/*
+ * Although multithread is part of the Arm spec, there are not many
+ * processors support multithread and current Xen on Arm assumes there
NIT: s/support/supporting
Sorry, it should have been spotted locally before sending. Anyway, I
will correct this in v4 with your Reviewed-by tag taken. Thanks for
pointing this out.
Kind regards,
Henry
__init smp_get_max_cpus(void)
~Michal
