On Wed, Sep 16, 2015 at 10:05:54PM -0700, [email protected] wrote: > > The patch below does not apply to the 4.2-stable tree. > If someone wants it applied there, or to any other stable or longterm > tree, then please email the backport, including the original git commit > id to <[email protected]>. > > thanks, > > greg k-h >
Hi greg, I found this patch is already in the 4.2-stable tree (commit id d7add05). Thanks, - Haozhong > ------------------ original commit in Linus's tree ------------------ > > From d7add05458084a5e3d65925764a02ca9c8202c1e Mon Sep 17 00:00:00 2001 > From: Haozhong Zhang <[email protected]> > Date: Fri, 7 Aug 2015 11:24:32 +0800 > Subject: [PATCH] KVM: x86: Use adjustment in guest cycles when handling > MSR_IA32_TSC_ADJUST > > 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 <[email protected]> > Cc: [email protected] > Signed-off-by: Paolo Bonzini <[email protected]> > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index c5e88a881899..8f0f6eca69da 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -2105,7 +2105,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct > msr_data *msr_info) > if (guest_cpuid_has_tsc_adjust(vcpu)) { > if (!msr_info->host_initiated) { > s64 adj = data - vcpu->arch.ia32_tsc_adjust_msr; > - kvm_x86_ops->adjust_tsc_offset(vcpu, adj, true); > + adjust_tsc_offset_guest(vcpu, adj); > } > vcpu->arch.ia32_tsc_adjust_msr = data; > } > -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
