Thread (59 messages) 59 messages, 2 authors, 2022-08-23
STALE1378d REVIEWED: 4 (3M)
Revisions (4)
  1. v3 [diff vs current]
  2. v4 [diff vs current]
  3. v5 current
  4. v6 [diff vs current]

[PATCH v5 13/26] KVM: VMX: Check CPU_BASED_{INTR,NMI}_WINDOW_EXITING in setup_vmcs_config()

From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: 2022-08-02 16:09:55
Also in: kvm, lkml
Subsystem: kernel virtual machine for x86 (kvm/x86), the rest, x86 architecture (32-bit and 64-bit) · Maintainers: Sean Christopherson, Paolo Bonzini, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen

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 <redacted>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.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 5429101eea87..554326651372 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2566,10 +2566,12 @@ 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,
@@ -4380,6 +4382,10 @@ 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;
 
-- 
2.35.3
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