>@@ -1503,6 +1503,18 @@ void vmx_vcpu_load_vmcs(struct kvm_vcpu *vcpu, int cpu,
> (unsigned long)(cpu_entry_stack(cpu) + 1));
> }
>
>+ /* Per-CPU FRED MSRs */
>+ if (kvm_cpu_cap_has(X86_FEATURE_FRED)) {
>+#ifdef CONFIG_X86_64
>+ vmcs_write64(HOST_IA32_FRED_RSP1, __this_cpu_ist_top_va(DB));
>+ vmcs_write64(HOST_IA32_FRED_RSP2, __this_cpu_ist_top_va(NMI));
>+ vmcs_write64(HOST_IA32_FRED_RSP3, __this_cpu_ist_top_va(DF));
>+#endif
>+ vmcs_write64(HOST_IA32_FRED_SSP1, 0);
>+ vmcs_write64(HOST_IA32_FRED_SSP2, 0);
>+ vmcs_write64(HOST_IA32_FRED_SSP3, 0);
Given SSP[1-3] are constant for now, how about asserting that host SSP[1-3] are
all zeros when KVM is loaded and moving their writes to vmx_set_constant_host_state()?
>+ }
>+
> vmx->loaded_vmcs->cpu = cpu;
> }
> }
>@@ -4366,6 +4378,12 @@ void vmx_set_constant_host_state(struct vcpu_vmx *vmx)
> */
> vmcs_write16(HOST_DS_SELECTOR, 0);
> vmcs_write16(HOST_ES_SELECTOR, 0);
>+
>+ /* FRED CONFIG and STKLVLS are the same on all CPUs. */
>+ if (kvm_cpu_cap_has(X86_FEATURE_FRED)) {
>+ vmcs_write64(HOST_IA32_FRED_CONFIG, kvm_host.fred_config);
>+ vmcs_write64(HOST_IA32_FRED_STKLVLS, kvm_host.fred_stklvls);
>+ }
> #else
> vmcs_write16(HOST_DS_SELECTOR, __KERNEL_DS); /* 22.2.4 */
> vmcs_write16(HOST_ES_SELECTOR, __KERNEL_DS); /* 22.2.4 */
