Clear FRED VM entry/exit controls when initializing a vCPU, and set these controls only if FRED is enumerated after set CPUID.
FRED VM entry/exit controls need to be set to establish context sufficient to support FRED event delivery immediately after VM entry and exit. However it is not required to save/load FRED MSRs for a non-FRED guest, which aren't supposed to access FRED MSRs.
A non-FRED guest should get #GP upon accessing FRED MSRs, otherwise it corrupts host FRED MSRs.
Tested-by: Shan Kang shan.kang@intel.com Signed-off-by: Xin Li xin3.li@intel.com --- arch/x86/kvm/vmx/vmx.c | 34 +++++++++++++++++++++++++++++++++- 1 file changed, 33 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 9186f41974ab..5d4786812664 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -4423,6 +4423,9 @@ static u32 vmx_vmentry_ctrl(void) if (cpu_has_perf_global_ctrl_bug()) vmentry_ctrl &= ~VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL;
+ /* Whether to load guest FRED MSRs is deferred until after set CPUID */ + vmentry_ctrl &= ~VM_ENTRY_LOAD_IA32_FRED; + return vmentry_ctrl; }
@@ -4458,7 +4461,13 @@ static u32 vmx_vmexit_ctrl(void)
static u64 vmx_secondary_vmexit_ctrl(void) { - return vmcs_config.secondary_vmexit_ctrl; + u64 secondary_vmexit_ctrl = vmcs_config.secondary_vmexit_ctrl; + + /* Whether to save/load FRED MSRs is deferred until after set CPUID */ + secondary_vmexit_ctrl &= ~(SECONDARY_VM_EXIT_SAVE_IA32_FRED | + SECONDARY_VM_EXIT_LOAD_IA32_FRED); + + return secondary_vmexit_ctrl; }
static void vmx_refresh_apicv_exec_ctrl(struct kvm_vcpu *vcpu) @@ -7785,10 +7794,33 @@ static void update_intel_pt_cfg(struct kvm_vcpu *vcpu) vmx->pt_desc.ctl_bitmask &= ~(0xfULL << (32 + i * 4)); }
+static void vmx_vcpu_config_fred_after_set_cpuid(struct kvm_vcpu *vcpu) +{ + struct vcpu_vmx *vmx = to_vmx(vcpu); + + if (!cpu_feature_enabled(X86_FEATURE_FRED) || + !guest_cpuid_has(vcpu, X86_FEATURE_FRED)) + return; + + /* Enable loading guest FRED MSRs from VMCS */ + vm_entry_controls_setbit(vmx, VM_ENTRY_LOAD_IA32_FRED); + + /* + * Enable saving guest FRED MSRs into VMCS and loading host FRED MSRs + * from VMCS. + */ + vm_exit_controls_setbit(vmx, VM_EXIT_ACTIVATE_SECONDARY_CONTROLS); + secondary_vm_exit_controls_setbit(vmx, + SECONDARY_VM_EXIT_SAVE_IA32_FRED | + SECONDARY_VM_EXIT_LOAD_IA32_FRED); +} + static void vmx_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu);
+ vmx_vcpu_config_fred_after_set_cpuid(vcpu); + /* * XSAVES is effectively enabled if and only if XSAVE is also exposed * to the guest. XSAVES depends on CR4.OSXSAVE, and CR4.OSXSAVE can be