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.
> + }
> +
> kvm_rsp_write(vcpu, vmcs12->guest_rsp);
> kvm_rip_write(vcpu, vmcs12->guest_rip);
> return 0;
> --
> 2.23.0.187.g17f5b7556c-goog
>
