RE: [PATCH 0/5] KVM: VMX: Drop MTRR virtualization, honor guest PAT

[Ma, XiangfeiX]

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

I have verified this method which can solve the issue.

-----Original Message-----
From: Zhao, Yan Y <yan.y.zhao@xxxxxxxxx> 
Sent: Friday, March 22, 2024 9:08 PM
To: Sean Christopherson <seanjc@xxxxxxxxxx>; Ma, XiangfeiX <xiangfeix.ma@xxxxxxxxx>; Hao, Xudong <xudong.hao@xxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>; Lai Jiangshan <jiangshanlai@xxxxxxxxx>; Paul E. McKenney <paulmck@xxxxxxxxxx>; Josh Triplett <josh@xxxxxxxxxxxxxxxx>; kvm@xxxxxxxxxxxxxxx; rcu@xxxxxxxxxxxxxxx; linux-kernel@vger.kernelorg; Tian, Kevin <kevin.tian@xxxxxxxxx>; Yiwei Zhang <zzyiwei@xxxxxxxxxx>
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);