[PATCH v4 0/7] Enlightened VMCS support for KVM on Hyper-V

From: Vitaly Kuznetsov
Date: Fri Mar 16 2018 - 10:22:31 EST


Changes since v3:
- Add Michael's Reviewed-by to PATCH2,5,6
- PATCH1:
- Decipher 'TLFS' and add a reference where it can be obtained
[Christoph Hellwig]
- PATCH4:
- remove vfree() from hv_cpu_die() [Thomas Gleixner]
- free hv_vp_assist_page() in the error path [Thomas Gleixner]
While on it, add cpuhp_remove_state() call when we fail to allocate
hypercall page to make the error path complete.
- check hv_vp_assist_page != NULL in hv_get_vp_assist_page()
[Thomas Gleixner]
- PATCH7:
- split off vmx_evmcs.h [Paolo Bonzini]
- merge get_evmcs_offset() and get_evmcs_offset_cf() [Paolo Bonzini]
- move evmcs_sanitize_exec_ctrls() to setup_vmcs_config [Paolo Bonzini]
- rename vmcs_load_enlightened() -> evmcs_load() [Paolo Bonzini]
- drop evmcs_sanitize_exec_ctrls() from dump_vmcs() [Paolo Bonzini]

When running nested KVM on Hyper-V it's possible to use so called
'Enlightened VMCS' and do normal memory reads/writes instead of
doing VMWRITE/VMREAD instructions. In addition, clean field mask
provides a huge room for optimization on L0's side.

Tight CPUID loop test shows significant speedup (E5-2667 v4 @ 3.20GHz):
Before: 18890 cycles
After: 8304 cycles

Ladi Prosek (1):
x86/kvm: rename HV_X64_MSR_APIC_ASSIST_PAGE to
HV_X64_MSR_VP_ASSIST_PAGE

Vitaly Kuznetsov (6):
x86/hyper-v: move hyperv.h out of uapi
x86/hyper-v: move definitions from TLFS to hyperv-tlfs.h
x86/hyper-v: allocate and use Virtual Processor Assist Pages
x86/hyper-v: define struct hv_enlightened_vmcs and clean field bits
x86/hyper-v: detect nested features
x86/kvm: use Enlightened VMCS when running on Hyper-V

MAINTAINERS | 2 +-
arch/x86/hyperv/hv_init.c | 45 ++-
arch/x86/include/asm/hyperv-tlfs.h | 702 +++++++++++++++++++++++++++++++++++
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/include/asm/mshyperv.h | 94 +----
arch/x86/include/uapi/asm/hyperv.h | 421 ---------------------
arch/x86/include/uapi/asm/kvm_para.h | 1 -
arch/x86/kernel/cpu/mshyperv.c | 21 +-
arch/x86/kvm/hyperv.c | 8 +-
arch/x86/kvm/lapic.h | 2 +-
arch/x86/kvm/vmx.c | 301 ++++++++++++++-
arch/x86/kvm/vmx_evmcs.h | 324 ++++++++++++++++
arch/x86/kvm/x86.c | 2 +-
drivers/hv/connection.c | 1 -
drivers/hv/hv.c | 1 -
drivers/hv/hyperv_vmbus.h | 1 +
drivers/hv/vmbus_drv.c | 1 -
include/linux/hyperv.h | 1 -
18 files changed, 1396 insertions(+), 533 deletions(-)
create mode 100644 arch/x86/include/asm/hyperv-tlfs.h
delete mode 100644 arch/x86/include/uapi/asm/hyperv.h
create mode 100644 arch/x86/kvm/vmx_evmcs.h

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2.14.3