https://github.com/torvalds/linux
Revision d7add05458084a5e3d65925764a02ca9c8202c1e authored by Haozhong Zhang on 07 August 2015, 03:24:32 UTC, committed by Paolo Bonzini on 07 August 2015, 11:28:03 UTC
When kvm_set_msr_common() handles a guest's write to MSR_IA32_TSC_ADJUST, it will calcuate an adjustment based on the data written by guest and then use it to adjust TSC offset by calling a call-back adjust_tsc_offset(). The 3rd parameter of adjust_tsc_offset() indicates whether the adjustment is in host TSC cycles or in guest TSC cycles. If SVM TSC scaling is enabled, adjust_tsc_offset() [i.e. svm_adjust_tsc_offset()] will first scale the adjustment; otherwise, it will just use the unscaled one. As the MSR write here comes from the guest, the adjustment is in guest TSC cycles. However, the current kvm_set_msr_common() uses it as a value in host TSC cycles (by using true as the 3rd parameter of adjust_tsc_offset()), which can result in an incorrect adjustment of TSC offset if SVM TSC scaling is enabled. This patch fixes this problem. Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com> Cc: stable@vger.linux.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1 parent 18c3626
Tip revision: d7add05458084a5e3d65925764a02ca9c8202c1e authored by Haozhong Zhang on 07 August 2015, 03:24:32 UTC
KVM: x86: Use adjustment in guest cycles when handling MSR_IA32_TSC_ADJUST
KVM: x86: Use adjustment in guest cycles when handling MSR_IA32_TSC_ADJUST
Tip revision: d7add05
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