mshv_vtl_main.c calls smp_send_reschedule() which expands to arch_smp_send_reschedule(). When CONFIG_MSHV_VTL=m, the module cannot access this symbol since it is not exported on arm64.
smp_send_reschedule() is used in mshv_vtl_cancel() to interrupt a vCPU thread running on another CPU. When a vCPU is looping in mshv_vtl_ioctl_return_to_lower_vtl(), it checks a per-CPU cancel flag before each VTL0 entry. Setting cancel=1 alone is not enough if the target CPU thread is sleeping - the IPI from smp_send_reschedule() kicks the remote CPU out of idle/sleep so it re-checks the cancel flag and exits the loop promptly. Other architectures (riscv, loongarch, powerpc) already export this symbol. Add the same EXPORT_SYMBOL_GPL for arm64. This is required for adding arm64 support in MSHV_VTL. Signed-off-by: Naman Jain <[email protected]> --- arch/arm64/kernel/smp.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 1aa324104afb..26b1a4456ceb 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -1152,6 +1152,7 @@ void arch_smp_send_reschedule(int cpu) { smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE); } +EXPORT_SYMBOL_GPL(arch_smp_send_reschedule); #ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL void arch_send_wakeup_ipi(unsigned int cpu) -- 2.43.0
