Tested-by: Xiangfei Ma <xiangfeix.ma@intel.com>

I have verified this method which can solve the issue.

-----Original Message-----
From: Zhao, Yan Y <yan.y.zhao@intel.com> 
Sent: Friday, March 22, 2024 9:08 PM
To: Sean Christopherson <seanjc@google.com>; Ma, XiangfeiX <xiangfeix.ma@intel.com>; Hao, Xudong <xudong.hao@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>; Lai Jiangshan <jiangshanlai@gmail.com>; Paul E. McKenney <paulmck@kernel.org>; Josh Triplett <josh@joshtriplett.org>; kvm@vger.kernel.org; rcu@vger.kernel.org; linux-kernel@vger.kernel.org; Tian, Kevin <kevin.tian@intel.com>; Yiwei Zhang <zzyiwei@google.com>
Subject: Re: [PATCH 0/5] KVM: VMX: Drop MTRR virtualization, honor guest PAT

Xiangfei found out an failure in kvm unit test rdtsc_vmexit_diff_test with below error log:
"FAIL: RDTSC to VM-exit delta too high in 100 of 100 iterations, last = 902
FAIL: Guest didn't run to completion."

Fixed it by adding below lines in the unit test rdtsc_vmexit_diff_test before enter guest in my side.
vmcs_write(HOST_PAT, 0x6);
vmcs_clear_bits(EXI_CONTROLS, EXI_SAVE_PAT); vmcs_set_bits(EXI_CONTROLS, EXI_LOAD_PAT);

Tested-by: Xiangfei Ma <xiangfeix.ma@intel.com>

Testing environment is based on the EMR-2S3 platform + CentOS 9(kernel version: 6.8.0-rc4).
Test cases include cpu, amx, umip, ptvmx, IPIv, vtd, PMU, SGX, kmv-unit-tests, kvm selftests, etc. And workload test on the guest using Netperf(bridge) and SPECJBB(passthrough NIC).
Except for the known issue and the previously mentioned "rdtsc_vmexit_diff_test", no other issue found.

-----Original Message-----
From: Ma, XiangfeiX 
Sent: Monday, March 25, 2024 2:56 PM
To: Zhao, Yan Y <yan.y.zhao@intel.com>; Sean Christopherson <seanjc@google.com>; Hao, Xudong <xudong.hao@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>; Lai Jiangshan <jiangshanlai@gmail.com>; Paul E. McKenney <paulmck@kernel.org>; Josh Triplett <josh@joshtriplett.org>; kvm@vger.kernel.org; rcu@vger.kernel.org; linux-kernel@vger.kernel.org; Tian, Kevin <kevin.tian@intel.com>; Yiwei Zhang <zzyiwei@google.com>
Subject: RE: [PATCH 0/5] KVM: VMX: Drop MTRR virtualization, honor guest PAT

Tested-by: Xiangfei Ma <xiangfeix.ma@intel.com>

I have verified this method which can solve the issue.

-----Original Message-----
From: Zhao, Yan Y <yan.y.zhao@intel.com> 
Sent: Friday, March 22, 2024 9:08 PM
To: Sean Christopherson <seanjc@google.com>; Ma, XiangfeiX <xiangfeix.ma@intel.com>; Hao, Xudong <xudong.hao@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>; Lai Jiangshan <jiangshanlai@gmail.com>; Paul E. McKenney <paulmck@kernel.org>; Josh Triplett <josh@joshtriplett.org>; kvm@vger.kernel.org; rcu@vger.kernel.org; linux-kernel@vger.kernel.org; Tian, Kevin <kevin.tian@intel.com>; Yiwei Zhang <zzyiwei@google.com>
Subject: Re: [PATCH 0/5] KVM: VMX: Drop MTRR virtualization, honor guest PAT

Xiangfei found out an failure in kvm unit test rdtsc_vmexit_diff_test with below error log:
"FAIL: RDTSC to VM-exit delta too high in 100 of 100 iterations, last = 902
FAIL: Guest didn't run to completion."

Fixed it by adding below lines in the unit test rdtsc_vmexit_diff_test before enter guest in my side.
vmcs_write(HOST_PAT, 0x6);
vmcs_clear_bits(EXI_CONTROLS, EXI_SAVE_PAT); vmcs_set_bits(EXI_CONTROLS, EXI_LOAD_PAT);