On Mon, Sep 16, 2019 at 02:17:42PM -0700, Oliver Upton wrote:
> On Mon, Sep 16, 2019 at 11:06:14AM -0700, Sean Christopherson wrote:
> > On Fri, Sep 06, 2019 at 02:03:06PM -0700, Oliver Upton wrote:
> > > Add condition to prepare_vmcs02 which loads IA32_PERF_GLOBAL_CTRL on
> > > VM-entry if the "load IA32_PERF_GLOBAL_CTRL" bit on the VM-entry control
> > > is set. Use kvm_set_msr() rather than directly writing to the field to
> > > avoid overwrite by atomic_switch_perf_msrs().
> > >
> > > Suggested-by: Jim Mattson <jmattson@xxxxxxxxxx>
> > > Co-developed-by: Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx>
> > > Signed-off-by: Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx>
> > > Signed-off-by: Oliver Upton <oupton@xxxxxxxxxx>
> > > Reviewed-by: Jim Mattson <jmattson@xxxxxxxxxx>
> > > Reviewed-by: Peter Shier <pshier@xxxxxxxxxx>
> > > ---
> > > arch/x86/kvm/vmx/nested.c | 11 +++++++++++
> > > 1 file changed, 11 insertions(+)
> > >
> > > diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> > > index b0ca34bf4d21..9ba90b38d74b 100644
> > > --- a/arch/x86/kvm/vmx/nested.c
> > > +++ b/arch/x86/kvm/vmx/nested.c
> > > @@ -2281,6 +2281,7 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
> > > {
> > > struct vcpu_vmx *vmx = to_vmx(vcpu);
> > > struct hv_enlightened_vmcs *hv_evmcs = vmx->nested.hv_evmcs;
> > > + struct msr_data msr_info;
> > > bool load_guest_pdptrs_vmcs12 = false;
> > >
> > > if (vmx->nested.dirty_vmcs12 || hv_evmcs) {
> > > @@ -2404,6 +2405,16 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
> > > if (!enable_ept)
> > > vcpu->arch.walk_mmu->inject_page_fault = vmx_inject_page_fault_nested;
> > >
> > > + if (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL) {
> > > + msr_info.host_initiated = false;
> > > + msr_info.index = MSR_CORE_PERF_GLOBAL_CTRL;
> > > + msr_info.data = vmcs12->guest_ia32_perf_global_ctrl;
> > > + if (kvm_set_msr(vcpu, &msr_info))
> > > + pr_debug_ratelimited(
> > > + "%s cannot write MSR (0x%x, 0x%llx)\n",
> > > + __func__, msr_info.index, msr_info.data);
> >
> > Same comment on printing the name. Might be work adding a helper function
> > or macro? That'd also avoid blasting past the 80-column guideline.
>
> Thanks for the review, Sean. I believe that in one of the prior sets I
> mailed out you had mentioned a macro for this as well, but was a fix
> throughout KVM. Shall I introduce the macro as part of this series, but
> only apply it to my changes (and fix other call sites later on)?
Heh, I'm not sure if by "KVM wide" I was thinking just interface to
kvm_set_msr() and kvm_get_msr(), or if I was thiking this specific
pr_debug line as well.
But, it's a moot point if we can pre-check the vmcs12 value and thus
WARN on failure here.
