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Subject[patch v2 0/8] Intel Processor Trace virtulization enabling
From: Chao Peng <>

Hi All,

Here is a patch-series which adding Processor Trace enabling in KVM guest. You can get It's software developer manuals from:

Intel Processor Trace (Intel PT) is an extension of Intel Architecture that captures information about software execution using dedicated hardware facilities that cause only minimal performance perturbation to the software being traced. Details on the Intel PT infrastructure and trace capabilities can be found in the Intel 64 and IA-32 Architectures Software Developer’s Manual, Volume 3C.

The suite of architecture changes serve to simplify the process of virtualizing Intel PT for use by a guest software. There are two primary elements to this new architecture support for VMX support improvements made for Intel PT.
1. Addition of a new guest IA32_RTIT_CTL value field to the VMCS.
— This serves to speed and simplify the process of disabling trace on VM exit, and restoring it on VM entry.
2. Enabling use of EPT to redirect PT output.
— This enables the VMM to elect to virtualize the PT output buffer using EPT. In this mode, the CPU will treat PT output addresses as Guest Physical Addresses (GPAs) and translate them using EPT. This means that Intel PT output reads (of the ToPA table) and writes (of trace output) can cause EPT violations, and other output events.

Processor Trace virtualization can be work in one of 3 possible modes by set new option "pt_mode". Default value is host guest mode.
a. system-wide: trace both host/guest and output to host buffer;
b. host-only: only trace host and output to host buffer;
c. host-guest: trace host/guest simultaneous and output to their respective buffer.

From v1:
- remove guest-only mode because guest-only mode can be covered by host-guest mode;
- always set "use GPA for processor tracing" in secondary execution control if it can be;
- trap RTIT_CTL read/write. Forbid write this msr when VMXON in L1 hypervisor.

Chao Peng (8):
perf/x86/intel/pt: Move Intel-PT MSR bit definitions to a public
perf/x86/intel/pt: change pt_cap_get() to a public function
KVM: x86: add Intel processor trace virtualization mode
KVM: x86: add Intel processor trace cpuid emulataion
KVM: x86: add Intel processor trace context for each vcpu
KVM: x86: Implement Intel processor trace context switch
KVM: x86: add Intel PT msr RTIT_CTL read/write
KVM: x86: Disable intercept for Intel processor trace MSRs

arch/x86/events/intel/pt.c | 3 +-
arch/x86/events/intel/pt.h | 55 -----------
arch/x86/include/asm/intel_pt.h | 26 ++++++
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/include/asm/msr-index.h | 35 +++++++
arch/x86/include/asm/vmx.h | 8 ++
arch/x86/kvm/cpuid.c | 23 ++++-
arch/x86/kvm/svm.c | 6 ++
arch/x86/kvm/vmx.c | 195 ++++++++++++++++++++++++++++++++++++++-
9 files changed, 290 insertions(+), 62 deletions(-)


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