Messages in this thread | | | Date | Wed, 2 Nov 2022 17:02:36 +0100 | Subject | Re: [PATCH 6/7] KVM: SVM: move MSR_IA32_SPEC_CTRL save/restore to assembly | From | Paolo Bonzini <> |
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On 11/2/22 16:28, Josh Poimboeuf wrote: > On Fri, Oct 28, 2022 at 07:07:22PM -0400, Paolo Bonzini wrote: >> +++ b/arch/x86/kvm/svm/svm.c >> @@ -3918,10 +3918,21 @@ static noinstr void svm_vcpu_enter_exit(struct kvm_vcpu *vcpu) >> struct vcpu_svm *svm = to_svm(vcpu); >> unsigned long vmcb_pa = svm->current_vmcb->pa; >> >> + /* >> + * For non-nested case: >> + * If the L01 MSR bitmap does not intercept the MSR, then we need to >> + * save it. >> + * >> + * For nested case: >> + * If the L02 MSR bitmap does not intercept the MSR, then we need to >> + * save it. >> + */ >> + bool spec_ctrl_intercepted = msr_write_intercepted(vcpu, MSR_IA32_SPEC_CTRL); > > This triggers a warning: > > vmlinux.o: warning: objtool: svm_vcpu_enter_exit+0x3d: call to svm_msrpm_offset() leaves .noinstr.text section > > svm_vcpu_enter_exit() is noinstr, but it's calling > msr_write_intercepted() which is not.
I suspect I didn't see it because it's inlined here, but it has to be fixed indeed.
> That's why in the VMX code I did the call to msr_write_intercepted() (in > __vmx_vcpu_run_flags) before calling vmx_vcpu_enter_exit().
Yes, it's easy to do the same and do it in svm_vcpu_run().
Paolo
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