Re: [PATCH] KVM: SVM: obey guest PAT

2017-11-10 Thread Radim Krčmář
2017-10-26 09:13+0200, Paolo Bonzini: > For many years some users of assigned devices have reported worse > performance on AMD processors with NPT than on AMD without NPT, > Intel or bare metal. > > The reason turned out to be that SVM is discarding the guest PAT > setting and uses the default

Re: [PATCH] KVM: SVM: obey guest PAT

2017-11-10 Thread Radim Krčmář
2017-10-26 09:13+0200, Paolo Bonzini: > For many years some users of assigned devices have reported worse > performance on AMD processors with NPT than on AMD without NPT, > Intel or bare metal. > > The reason turned out to be that SVM is discarding the guest PAT > setting and uses the default

Re: [PATCH] KVM: SVM: obey guest PAT

2017-10-26 Thread Nick Sarnie
On Thu, Oct 26, 2017 at 4:17 AM, David Hildenbrand wrote: > On 26.10.2017 09:13, Paolo Bonzini wrote: >> For many years some users of assigned devices have reported worse >> performance on AMD processors with NPT than on AMD without NPT, >> Intel or bare metal. >> >> The reason

Re: [PATCH] KVM: SVM: obey guest PAT

2017-10-26 Thread Nick Sarnie
On Thu, Oct 26, 2017 at 4:17 AM, David Hildenbrand wrote: > On 26.10.2017 09:13, Paolo Bonzini wrote: >> For many years some users of assigned devices have reported worse >> performance on AMD processors with NPT than on AMD without NPT, >> Intel or bare metal. >> >> The reason turned out to be

Re: [PATCH] KVM: SVM: obey guest PAT

2017-10-26 Thread David Hildenbrand
On 26.10.2017 09:13, Paolo Bonzini wrote: > For many years some users of assigned devices have reported worse > performance on AMD processors with NPT than on AMD without NPT, > Intel or bare metal. > > The reason turned out to be that SVM is discarding the guest PAT > setting and uses the

Re: [PATCH] KVM: SVM: obey guest PAT

2017-10-26 Thread David Hildenbrand
On 26.10.2017 09:13, Paolo Bonzini wrote: > For many years some users of assigned devices have reported worse > performance on AMD processors with NPT than on AMD without NPT, > Intel or bare metal. > > The reason turned out to be that SVM is discarding the guest PAT > setting and uses the

[PATCH] KVM: SVM: obey guest PAT

2017-10-26 Thread Paolo Bonzini
For many years some users of assigned devices have reported worse performance on AMD processors with NPT than on AMD without NPT, Intel or bare metal. The reason turned out to be that SVM is discarding the guest PAT setting and uses the default (PA0=PA4=WB, PA1=PA5=WT, PA2=PA6=UC-, PA3=UC). The

[PATCH] KVM: SVM: obey guest PAT

2017-10-26 Thread Paolo Bonzini
For many years some users of assigned devices have reported worse performance on AMD processors with NPT than on AMD without NPT, Intel or bare metal. The reason turned out to be that SVM is discarding the guest PAT setting and uses the default (PA0=PA4=WB, PA1=PA5=WT, PA2=PA6=UC-, PA3=UC). The