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From: Like Xu <like.xu@linux.intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <seanjc@google.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 0/4] KVM: x86/pmu: Guest Architectural LBR Enabling
Date: Wed,  3 Feb 2021 21:57:10 +0800	[thread overview]
Message-ID: <20210203135714.318356-1-like.xu@linux.intel.com> (raw)

Hi geniuses,

Please help review the new version of Arch LBR enabling on
KVM based on the latest kvm/queue tree.

The Architectural Last Branch Records (LBRs) is publiced
in the 319433-040 release of Intel Architecture Instruction
Set Extensions and Future Features Programming Reference[0].

The main advantages for the Arch LBR users are [1]:
- Faster context switching due to XSAVES support and faster reset of
  LBR MSRs via the new DEPTH MSR
- Faster LBR read for a non-PEBS event due to XSAVES support, which
  lowers the overhead of the NMI handler. (For a PEBS event, the LBR
  information is recorded in the PEBS records. There is no impact on
  the PEBS event.)
- Linux kernel can support the LBR features without knowing the model
  number of the current CPU.

Please check more details in each commit and feel free to comment.

[0] https://software.intel.com/content/www/us/en/develop/download/
intel-architecture-instruction-set-extensions-and-future-features-programming-reference.html
[1] https://lore.kernel.org/lkml/1593780569-62993-1-git-send-email-kan.liang@linux.intel.com/

---
v1->v2 Changelog:
- rebased on the latest kvm/queue tree;
- refine some comments for guest usage;

Previous:
https://lore.kernel.org/kvm/20200731074402.8879-1-like.xu@linux.intel.com/

Like Xu (4):
  KVM: vmx/pmu: Add MSR_ARCH_LBR_DEPTH emulation for Arch LBR
  KVM: vmx/pmu: Add MSR_ARCH_LBR_CTL emulation for Arch LBR
  KVM: vmx/pmu: Add Arch LBR emulation and its VMCS field
  KVM: x86: Expose Architectural LBR CPUID and its XSAVES bit

 arch/x86/include/asm/vmx.h      |  4 ++
 arch/x86/kvm/cpuid.c            | 23 ++++++++++
 arch/x86/kvm/vmx/capabilities.h | 25 +++++++----
 arch/x86/kvm/vmx/pmu_intel.c    | 74 +++++++++++++++++++++++++++++++--
 arch/x86/kvm/vmx/vmx.c          | 15 ++++++-
 arch/x86/kvm/vmx/vmx.h          |  3 ++
 arch/x86/kvm/x86.c              | 10 ++++-
 7 files changed, 140 insertions(+), 14 deletions(-)

-- 
2.29.2


             reply	other threads:[~2021-02-03 14:05 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-03 13:57 Like Xu [this message]
2021-02-03 13:57 ` [PATCH v2 1/4] KVM: vmx/pmu: Add MSR_ARCH_LBR_DEPTH emulation for Arch LBR Like Xu
2021-03-01 22:34   ` Sean Christopherson
2021-03-02  2:52     ` Like Xu
2021-02-03 13:57 ` [PATCH v2 2/4] KVM: vmx/pmu: Add MSR_ARCH_LBR_CTL " Like Xu
2021-02-03 13:57 ` [PATCH v2 3/4] KVM: vmx/pmu: Add Arch LBR emulation and its VMCS field Like Xu
2021-02-03 13:57 ` [PATCH v2 4/4] KVM: x86: Expose Architectural LBR CPUID and its XSAVES bit Like Xu
2021-02-03 14:37   ` Paolo Bonzini
2021-02-04  0:59     ` Xu, Like
2021-02-05  8:16       ` Xu, Like
2021-02-05 11:00         ` Paolo Bonzini
2021-02-07  1:02           ` Xu, Like
2021-02-08 10:31             ` Paolo Bonzini
2021-04-14  1:00               ` Xu, Like

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