diff options
Diffstat (limited to 'arch/x86/kernel/cpu/mshyperv.c')
| -rw-r--r-- | arch/x86/kernel/cpu/mshyperv.c | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 05ef1f4550cb..f628e3dc150f 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -366,9 +366,38 @@ static void __init ms_hyperv_init_platform(void) #endif } +static bool __init ms_hyperv_x2apic_available(void) +{ + return x2apic_supported(); +} + +/* + * If ms_hyperv_msi_ext_dest_id() returns true, hyperv_prepare_irq_remapping() + * returns -ENODEV and the Hyper-V IOMMU driver is not used; instead, the + * generic support of the 15-bit APIC ID is used: see __irq_msi_compose_msg(). + * + * Note: for a VM on Hyper-V, the I/O-APIC is the only device which + * (logically) generates MSIs directly to the system APIC irq domain. + * There is no HPET, and PCI MSI/MSI-X interrupts are remapped by the + * pci-hyperv host bridge. + */ +static bool __init ms_hyperv_msi_ext_dest_id(void) +{ + u32 eax; + + eax = cpuid_eax(HYPERV_CPUID_VIRT_STACK_INTERFACE); + if (eax != HYPERV_VS_INTERFACE_EAX_SIGNATURE) + return false; + + eax = cpuid_eax(HYPERV_CPUID_VIRT_STACK_PROPERTIES); + return eax & HYPERV_VS_PROPERTIES_EAX_EXTENDED_IOAPIC_RTE; +} + const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = { .name = "Microsoft Hyper-V", .detect = ms_hyperv_platform, .type = X86_HYPER_MS_HYPERV, + .init.x2apic_available = ms_hyperv_x2apic_available, + .init.msi_ext_dest_id = ms_hyperv_msi_ext_dest_id, .init.init_platform = ms_hyperv_init_platform, }; |