Implement XEN_SYSCTL_CPU_HOTPLUG_{ONLINE,OFFLINE} calls to allow for
enabling/disabling CPU cores in runtime.For now this operations only support Arm64. For proper Arm32 support, there needs to be a mechanism to free per-cpu page tables, allocated in init_domheap_mappings. Also, hotplug is not supported if ITS, FFA, or TEE is enabled, as they use non-static IRQ actions. Create a Kconfig option RUNTIME_CPU_CONTROL that reflects this constraints. Signed-off-by: Mykyta Poturai <[email protected]> v3->v4: * don't reimplement cpu_up/down helpers * add Kconfig option * fixup formatting v2->v3: * no changes v1->v2: * remove SMT ops * remove cpu == 0 checks * add XSM hooks * only implement for 64bit Arm --- xen/arch/arm/Kconfig | 4 ++++ xen/arch/arm/sysctl.c | 32 ++++++++++++++++++++++++++++++++ 2 files changed, 36 insertions(+) diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig index cf6af68299..931ae51575 100644 --- a/xen/arch/arm/Kconfig +++ b/xen/arch/arm/Kconfig @@ -274,6 +274,10 @@ config PCI_PASSTHROUGH help This option enables PCI device passthrough +config RUNTIME_CPU_CONTROL + def_bool y + depends on ARM_64 && !TEE && !FFA && !HAS_ITS + endmenu menu "ARM errata workaround via the alternative framework" diff --git a/xen/arch/arm/sysctl.c b/xen/arch/arm/sysctl.c index 32cab4feff..3c4e29d82c 100644 --- a/xen/arch/arm/sysctl.c +++ b/xen/arch/arm/sysctl.c @@ -12,6 +12,7 @@ #include <xen/dt-overlay.h> #include <xen/errno.h> #include <xen/hypercall.h> +#include <xsm/xsm.h> #include <asm/arm64/sve.h> #include <public/sysctl.h> @@ -23,6 +24,33 @@ void arch_do_physinfo(struct xen_sysctl_physinfo *pi) XEN_SYSCTL_PHYSCAP_ARM_SVE_MASK); } +static long cpu_hotplug_sysctl(struct xen_sysctl_cpu_hotplug *hotplug) +{ +#ifdef CONFIG_RUNTIME_CPU_CONTROL + int ret; + + switch ( hotplug->op ) + { + case XEN_SYSCTL_CPU_HOTPLUG_ONLINE: + ret = xsm_resource_plug_core(XSM_HOOK); + if ( ret ) + return ret; + return continue_hypercall_on_cpu(0, cpu_up_helper, _p(hotplug->cpu)); + + case XEN_SYSCTL_CPU_HOTPLUG_OFFLINE: + ret = xsm_resource_unplug_core(XSM_HOOK); + if ( ret ) + return ret; + return continue_hypercall_on_cpu(0, cpu_down_helper, _p(hotplug->cpu)); + + default: + return -EOPNOTSUPP; + } +#else + return -EOPNOTSUPP; +#endif +} + long arch_do_sysctl(struct xen_sysctl *sysctl, XEN_GUEST_HANDLE_PARAM(xen_sysctl_t) u_sysctl) { @@ -34,6 +62,10 @@ long arch_do_sysctl(struct xen_sysctl *sysctl, ret = dt_overlay_sysctl(&sysctl->u.dt_overlay); break; + case XEN_SYSCTL_cpu_hotplug: + ret = cpu_hotplug_sysctl(&sysctl->u.cpu_hotplug); + break; + default: ret = -ENOSYS; break; -- 2.51.2
