diff options
| author | Maxim Levitsky <mlevitsk@redhat.com> | 2021-09-14 17:48:24 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-10-01 09:44:46 +0200 |
| commit | 5228eb96a4875f8cf5d61d486e3795ac14df8904 (patch) | |
| tree | 4cf9de3e3e9de6f84648c7e4a0cc7c39775e1498 /arch/x86/kvm/svm/nested.c | |
| parent | KVM: x86: SVM: add module param to control TSC scaling (diff) | |
| download | linux-5228eb96a4875f8cf5d61d486e3795ac14df8904.tar.xz linux-5228eb96a4875f8cf5d61d486e3795ac14df8904.zip | |
KVM: x86: nSVM: implement nested TSC scaling
This was tested by booting a nested guest with TSC=1Ghz,
observing the clocks, and doing about 100 cycles of migration.
Note that qemu patch is needed to support migration because
of a new MSR that needs to be placed in the migration state.
The patch will be sent to the qemu mailing list soon.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210914154825.104886-14-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/svm/nested.c')
| -rw-r--r-- | arch/x86/kvm/svm/nested.c | 29 |
1 files changed, 27 insertions, 2 deletions
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index ec3e926b20dd..31fd4bd334c2 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -538,8 +538,17 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm) if (nested_npt_enabled(svm)) nested_svm_init_mmu_context(vcpu); - svm->vmcb->control.tsc_offset = vcpu->arch.tsc_offset = - vcpu->arch.l1_tsc_offset + svm->nested.ctl.tsc_offset; + vcpu->arch.tsc_offset = kvm_calc_nested_tsc_offset( + vcpu->arch.l1_tsc_offset, + svm->nested.ctl.tsc_offset, + svm->tsc_ratio_msr); + + svm->vmcb->control.tsc_offset = vcpu->arch.tsc_offset; + + if (svm->tsc_ratio_msr != kvm_default_tsc_scaling_ratio) { + WARN_ON(!svm->tsc_scaling_enabled); + nested_svm_update_tsc_ratio_msr(vcpu); + } svm->vmcb->control.int_ctl = (svm->nested.ctl.int_ctl & int_ctl_vmcb12_bits) | @@ -824,6 +833,12 @@ int nested_svm_vmexit(struct vcpu_svm *svm) vmcb_mark_dirty(svm->vmcb, VMCB_INTERCEPTS); } + if (svm->tsc_ratio_msr != kvm_default_tsc_scaling_ratio) { + WARN_ON(!svm->tsc_scaling_enabled); + vcpu->arch.tsc_scaling_ratio = vcpu->arch.l1_tsc_scaling_ratio; + svm_write_tsc_multiplier(vcpu, vcpu->arch.tsc_scaling_ratio); + } + svm->nested.ctl.nested_cr3 = 0; /* @@ -1211,6 +1226,16 @@ int nested_svm_exit_special(struct vcpu_svm *svm) return NESTED_EXIT_CONTINUE; } +void nested_svm_update_tsc_ratio_msr(struct kvm_vcpu *vcpu) +{ + struct vcpu_svm *svm = to_svm(vcpu); + + vcpu->arch.tsc_scaling_ratio = + kvm_calc_nested_tsc_multiplier(vcpu->arch.l1_tsc_scaling_ratio, + svm->tsc_ratio_msr); + svm_write_tsc_multiplier(vcpu, vcpu->arch.tsc_scaling_ratio); +} + static int svm_get_nested_state(struct kvm_vcpu *vcpu, struct kvm_nested_state __user *user_kvm_nested_state, u32 user_data_size) |