linux-kernel - [PATCH v2 0/3] KVM: VMX: Stub out enable

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Date:   Sat, 11 Feb 2023 00:35:31 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2 0/3] KVM: VMX: Stub out enable_evmcs static key

Stub out and rename the eVMCS static key when CONFIG_HYPERV=n.  gcc (as of
gcc-12) isn't clever enough to elide the nop placeholder when there's no
code guarded by a static branch.  With gcc-12, because of the vast number
of VMCS accesses, eliminating the nops reduces the size of kvm-intel.ko by
~7.5% (200KiB).

Please holler if you would rather patch 3 be squashed into patch 2, i.e.
add the wrapper and rename the key in one go.  I split them because the
combined changelog was getting into "here's a list of changes" territory.

Patch 1 is tangentially related cleanup.

Applies on `git@...hub.com:kvm-x86/linux.git vmx`.

v2:
 - Collect reviews. [Vitaly]
 - Rename wrapper. [Vitaly, Paolo]
 - Rename key too.

v1: https://lore.kernel.org/all/20230208205430.1424667-1-seanjc@google.com

Sean Christopherson (3):
  KVM: nVMX: Move EVMCS1_SUPPORT_* macros to hyperv.c
  KVM: VMX: Stub out enable_evmcs static key for CONFIG_HYPERV=n
  KVM: VMX: Rename "KVM is using eVMCS" static key to match its wrapper

 arch/x86/kvm/vmx/hyperv.c  | 107 +++++++++++++++++++++++++++++++++-
 arch/x86/kvm/vmx/hyperv.h  | 115 +++----------------------------------
 arch/x86/kvm/vmx/vmx.c     |  17 +++---
 arch/x86/kvm/vmx/vmx_ops.h |  22 +++----
 4 files changed, 133 insertions(+), 128 deletions(-)

base-commit: 93827a0a36396f2fd6368a54a020f420c8916e9b
-- 
2.39.1.581.gbfd45094c4-goog