[RFC PATCH v6 23/36] KVM: VMX: Check CPU_BASED_{INTR,NMI}_WINDOW_EXITING in setup_vmcs_config()

Sean Christopherson
2022-08-24T03:04:36Z

CPU_BASED_{INTR,NMI}_WINDOW_EXITING controls are toggled dynamically by
vmx_enable_{irq,nmi}_window, handle_interrupt_window(), handle_nmi_window()
but setup_vmcs_config() doesn't check their existence. Add the check and
filter the controls out in vmx_exec_control().

Note: KVM explicitly supports CPUs without VIRTUAL_NMIS and all these CPUs
are supposedly lacking NMI_WINDOW_EXITING too. Adjust cpu_has_virtual_nmis()
accordingly.

No functional change intended.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/vmx/capabilities.h | 3 ++-
arch/x86/kvm/vmx/vmx.c | 8 +++++++-
2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx/capabilities.h b/arch/x86/kvm/vmx/capabilities.h
index c5e5dfef69c7..faee1db8b0e0 100644
--- a/arch/x86/kvm/vmx/capabilities.h
+++ b/arch/x86/kvm/vmx/capabilities.h
@@ -82,7 +82,8 @@ static inline bool cpu_has_vmx_basic_inout(void)

static inline bool cpu_has_virtual_nmis(void)
{
- return vmcs_config.pin_based_exec_ctrl & PIN_BASED_VIRTUAL_NMIS;
+ return vmcs_config.pin_based_exec_ctrl & PIN_BASED_VIRTUAL_NMIS &&
+ vmcs_config.cpu_based_exec_ctrl & CPU_BASED_NMI_WINDOW_EXITING;
}

static inline bool cpu_has_vmx_preemption_timer(void)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index eff38cbe6d35..7acbe43030e4 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2560,10 +2560,12 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf,
CPU_BASED_MWAIT_EXITING |
CPU_BASED_MONITOR_EXITING |
CPU_BASED_INVLPG_EXITING |
- CPU_BASED_RDPMC_EXITING;
+ CPU_BASED_RDPMC_EXITING |
+ CPU_BASED_INTR_WINDOW_EXITING;

opt = CPU_BASED_TPR_SHADOW |
CPU_BASED_USE_MSR_BITMAPS |
+ CPU_BASED_NMI_WINDOW_EXITING |
CPU_BASED_ACTIVATE_SECONDARY_CONTROLS |
CPU_BASED_ACTIVATE_TERTIARY_CONTROLS;
if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_PROCBASED_CTLS,
@@ -4374,6 +4376,10 @@ static u32 vmx_exec_control(struct vcpu_vmx *vmx)
{
u32 exec_control = vmcs_config.cpu_based_exec_ctrl;

+ /* INTR_WINDOW_EXITING and NMI_WINDOW_EXITING are toggled dynamically */
+ exec_control &= ~(CPU_BASED_INTR_WINDOW_EXITING |
+ CPU_BASED_NMI_WINDOW_EXITING);
+
if (vmx->vcpu.arch.switch_db_regs & KVM_DEBUGREG_WONT_EXIT)
exec_control &= ~CPU_BASED_MOV_DR_EXITING;

--
2.37.1.595.g718a3a8f04-goog