Allow selecting the default x2APIC destination mode from Kconfig. Note the default destination mode is still Logical (Cluster) mode.
Signed-off-by: Roger Pau Monné <[email protected]> --- xen/arch/x86/Kconfig | 29 +++++++++++++++++++++++++++++ xen/arch/x86/genapic/x2apic.c | 6 ++++-- 2 files changed, 33 insertions(+), 2 deletions(-) diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig index 1e31edc99f..f560dc13f4 100644 --- a/xen/arch/x86/Kconfig +++ b/xen/arch/x86/Kconfig @@ -226,6 +226,35 @@ config XEN_ALIGN_2M endchoice +choice + prompt "x2APIC default destination mode" + default X2APIC_LOGICAL + ---help--- + Specify default destination mode for x2APIC. + + If unsure, choose "Logical". + +config X2APIC_LOGICAL + bool "Logical mode" + ---help--- + Use Logical Destination mode. + + When using this mode APICs are addressed using the Logical + Destination mode, which allows for optimized IPI sending, + but also reduces the amount of vectors available for external + interrupts when compared to physical mode. + +config X2APIC_PHYS + bool "Physical mode" + ---help--- + Use Physical Destination mode. + + When using this mode APICs are addressed using the Physical + Destination mode, which allows using all dynamic vectors on + each CPU independently. + +endchoice + config GUEST bool diff --git a/xen/arch/x86/genapic/x2apic.c b/xen/arch/x86/genapic/x2apic.c index de5032f202..4b9bbe2f3e 100644 --- a/xen/arch/x86/genapic/x2apic.c +++ b/xen/arch/x86/genapic/x2apic.c @@ -228,7 +228,7 @@ static struct notifier_block x2apic_cpu_nfb = { .notifier_call = update_clusterinfo }; -static s8 __initdata x2apic_phys = -1; /* By default we use logical cluster mode. */ +static int8_t __initdata x2apic_phys = -1; boolean_param("x2apic_phys", x2apic_phys); const struct genapic *__init apic_x2apic_probe(void) @@ -241,7 +241,9 @@ const struct genapic *__init apic_x2apic_probe(void) * the usage of the high 16 bits to hold the cluster ID. */ x2apic_phys = !iommu_intremap || - (acpi_gbl_FADT.flags & ACPI_FADT_APIC_PHYSICAL); + (acpi_gbl_FADT.flags & ACPI_FADT_APIC_PHYSICAL) || + (IS_ENABLED(CONFIG_X2APIC_PHYS) && + !(acpi_gbl_FADT.flags & ACPI_FADT_APIC_CLUSTER)); } else if ( !x2apic_phys ) switch ( iommu_intremap ) -- 2.36.1
