kvm: handle host mode irqs 0

Changes to v2:
--------------
- [5/8] ("x86/KVM/VMX: introduce per-host-cpu analogue of ->l1tf_flush_l1d"):
use 'unsigned char' in place of former 'bool' for ->kvm_cpu_l1tf_flush_l1d (Peter Ziljstra). Update kvm_{set,clear}_cpu_l1tf_flush_l1d() to write '1' resp. '0' instead of true and false.

I retained Paolo's Reviewed-by from v2 because this change looks innocent enough.

Changes to v1 (the initial RFC series):
---------------------------------------
turn the kernel_mode_irq_gen per-cpu counter into a latch flag (Paolo Bonzini). Group it into irq_cpustat_t for cache locality (Peter Zijlstra). Set it from C rather than asm entry code (Andi Kleen).

Details
- [1-3/8]: unchanged

- [4/8] ("x86/irq: demote irq_cpustat_t's ->__softirq_pending to u16"): new, prerequisite for [5/8].

- [5/8] ("x86/KVM/VMX: introduce per-host-cpu analogue of ->l1tf_flush_l1d"):
roughly corresponds to former [5/6] ("x86/KVM/VMX: flush L1d upon interrupt after VMEXIT"). Introduce the new latch flag rather than taking that kernel_mode_irq_gen snapshot.

- [6/8] ("x86: don't include linux/irq.h from asm/hardirq.h"): new, prerequisite for [7/8].
I tested ARCH=i386 and ARCH=x86_64 allmodconfig compilations. (For i386 I had to disable CONFIG_BPFILTER_UMH because of a cross compilation issue.)

- [7/8] ("x86: let interrupt handlers set kvm_cpu_l1tf_flush_l1d"):
roughly corresponds to former [4/6] ("x86: implement kernel mode irq tracking"). Replace that kernel_mode_irq_gen increment from entry code by setting the new latch flag from entering_irq() & Co.

- [8/8] ("x86/KVM/VMX: don't set ->l1tf_flush_l1d from vmx_handle_external_intr()"):
this is the original [6/6] with its changelog slightly adjusted.

Nicolai Stange (8):
x86/KVM/VMX: don't set ->l1tf_flush_l1d to true from vmx_l1d_flush() x86/KVM/VMX: replace 'vmx_l1d_flush_always' with 'vmx_l1d_flush_cond' x86/KVM/VMX: move the ->l1tf_flush_l1d test to vmx_l1d_flush() x86/irq: demote irq_cpustat_t's ->__softirq_pending to u16 x86/KVM/VMX: introduce per-host-cpu analogue of ->l1tf_flush_l1d
x86: don't include linux/irq.h from asm/hardirq.h
x86: let interrupt handlers set kvm_cpu_l1tf_flush_l1d x86/KVM/VMX: don't set ->l1tf_flush_l1d from
vmx_handle_external_intr()

 arch/x86/include/asm/apic.h                        |  3 ++
 arch/x86/include/asm/dmi.h                         |  2 +-
 arch/x86/include/asm/hardirq.h                     | 27 ++++++++++++--
 arch/x86/include/asm/kvm_host.h                    |  1 +
 arch/x86/kernel/apic/apic.c                        |  1 +
 arch/x86/kernel/apic/io_apic.c                     |  1 +
 arch/x86/kernel/apic/msi.c                         |  1 +
 arch/x86/kernel/apic/vector.c                      |  1 +
 arch/x86/kernel/fpu/core.c                         |  1 +
 arch/x86/kernel/hpet.c                             |  1 +
 arch/x86/kernel/i8259.c                            |  1 +
 arch/x86/kernel/idt.c                              |  1 +
 arch/x86/kernel/irq.c                              |  1 +
 arch/x86/kernel/irq_32.c                           |  1 +
 arch/x86/kernel/irq_64.c                           |  1 +
 arch/x86/kernel/irqinit.c                          |  1 +
 arch/x86/kernel/smp.c                              |  1 +
 arch/x86/kernel/smpboot.c                          |  1 +
 arch/x86/kernel/time.c                             |  1 +
 arch/x86/kvm/vmx.c                                 | 42 +++++++++++++---------
 arch/x86/mm/pti.c                                  |  1 +
 .../intel-mid/device_libs/platform_mrfld_wdt.c     |  1 +
 arch/x86/platform/uv/tlb_uv.c                      |  1 +
 arch/x86/xen/enlighten.c                           |  1 +
 drivers/gpu/drm/i915/i915_pmu.c                    |  1 +
 drivers/gpu/drm/i915/intel_lpe_audio.c             |  1 +
 drivers/pci/controller/pci-hyperv.c                |  1 +
 27 files changed, 78 insertions(+), 19 deletions(-)

2.13.7