[PATCH v8 081/103] KVM: VMX: Move NMI/exception handler to common helper

From: isaku.yamahata@intel.com
To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: isaku.yamahata@intel.com, isaku.yamahata@gmail.com,
	Paolo Bonzini <pbonzini@redhat.com>,
	erdemaktas@google.com, Sean Christopherson <seanjc@google.com>,
	Sagi Shahar <sagis@google.com>
Subject: [PATCH v8 081/103] KVM: VMX: Move NMI/exception handler to common helper
Date: Sun,  7 Aug 2022 15:02:06 -0700	[thread overview]
Message-ID: <b49bd709938d1c31a00f2381baf835fd5523b919.1659854791.git.isaku.yamahata@intel.com> (raw)
In-Reply-To: <cover.1659854790.git.isaku.yamahata@intel.com>

From: Sean Christopherson <sean.j.christopherson@intel.com>

TDX mostly handles NMI/exception exit mostly the same to VMX case.  The
difference is how to retrieve exit qualification.  To share the code with
TDX, move NMI/exception to a common header, common.h.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
---
 arch/x86/kvm/vmx/common.h | 70 ++++++++++++++++++++++++++++++++++
 arch/x86/kvm/vmx/vmx.c    | 79 ++++-----------------------------------
 2 files changed, 78 insertions(+), 71 deletions(-)

diff --git a/arch/x86/kvm/vmx/common.h b/arch/x86/kvm/vmx/common.h
index 1522e9e6851b..fd5ed3c0f894 100644
--- a/arch/x86/kvm/vmx/common.h
+++ b/arch/x86/kvm/vmx/common.h
@@ -4,8 +4,78 @@
 
 #include <linux/kvm_host.h>
 
+#include <asm/traps.h>
+
 #include "posted_intr.h"
 #include "mmu.h"
+#include "vmcs.h"
+#include "x86.h"
+
+extern unsigned long vmx_host_idt_base;
+void vmx_do_interrupt_nmi_irqoff(unsigned long entry);
+
+static inline void vmx_handle_interrupt_nmi_irqoff(struct kvm_vcpu *vcpu,
+					       unsigned long entry)
+{
+       bool is_nmi = entry == (unsigned long)asm_exc_nmi_noist;
+
+       kvm_before_interrupt(vcpu, is_nmi ? KVM_HANDLING_NMI : KVM_HANDLING_IRQ);
+       vmx_do_interrupt_nmi_irqoff(entry);
+       kvm_after_interrupt(vcpu);
+}
+
+static inline void vmx_handle_nm_fault_irqoff(struct kvm_vcpu *vcpu)
+{
+	/*
+	 * Save xfd_err to guest_fpu before interrupt is enabled, so the
+	 * MSR value is not clobbered by the host activity before the guest
+	 * has chance to consume it.
+	 *
+	 * Do not blindly read xfd_err here, since this exception might
+	 * be caused by L1 interception on a platform which doesn't
+	 * support xfd at all.
+	 *
+	 * Do it conditionally upon guest_fpu::xfd. xfd_err matters
+	 * only when xfd contains a non-zero value.
+	 *
+	 * Queuing exception is done in vmx_handle_exit. See comment there.
+	 */
+	if (vcpu->arch.guest_fpu.fpstate->xfd)
+		rdmsrl(MSR_IA32_XFD_ERR, vcpu->arch.guest_fpu.xfd_err);
+}
+
+static inline void vmx_handle_exception_nmi_irqoff(struct kvm_vcpu *vcpu,
+						   u32 intr_info)
+{
+	const unsigned long nmi_entry = (unsigned long)asm_exc_nmi_noist;
+
+	/* if exit due to PF check for async PF */
+	if (is_page_fault(intr_info))
+		vcpu->arch.apf.host_apf_flags = kvm_read_and_reset_apf_flags();
+	/* if exit due to NM, handle before interrupts are enabled */
+	else if (is_nm_fault(intr_info))
+		vmx_handle_nm_fault_irqoff(vcpu);
+	/* Handle machine checks before interrupts are enabled */
+	else if (is_machine_check(intr_info))
+		kvm_machine_check();
+	/* We need to handle NMIs before interrupts are enabled */
+	else if (is_nmi(intr_info))
+		vmx_handle_interrupt_nmi_irqoff(vcpu, nmi_entry);
+}
+
+static inline void vmx_handle_external_interrupt_irqoff(struct kvm_vcpu *vcpu,
+							u32 intr_info)
+{
+	unsigned int vector = intr_info & INTR_INFO_VECTOR_MASK;
+	gate_desc *desc = (gate_desc *)vmx_host_idt_base + vector;
+
+	if (KVM_BUG(!is_external_intr(intr_info), vcpu->kvm,
+	    "KVM: unexpected VM-Exit interrupt info: 0x%x", intr_info))
+		return;
+
+	vmx_handle_interrupt_nmi_irqoff(vcpu, gate_offset(desc));
+	vcpu->arch.at_instruction_boundary = true;
+}
 
 static inline int __vmx_handle_ept_violation(struct kvm_vcpu *vcpu, gpa_t gpa,
 					     unsigned long exit_qualification)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 4ff998bf374b..e5aa805f6db4 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -527,7 +527,7 @@ static inline void vmx_segment_cache_clear(struct vcpu_vmx *vmx)
 	vmx->segment_cache.bitmask = 0;
 }
 
-static unsigned long host_idt_base;
+unsigned long vmx_host_idt_base;
 
 #if IS_ENABLED(CONFIG_HYPERV)
 static bool __read_mostly enlightened_vmcs = true;
@@ -4186,7 +4186,7 @@ void vmx_set_constant_host_state(struct vcpu_vmx *vmx)
 	vmcs_write16(HOST_SS_SELECTOR, __KERNEL_DS);  /* 22.2.4 */
 	vmcs_write16(HOST_TR_SELECTOR, GDT_ENTRY_TSS*8);  /* 22.2.4 */
 
-	vmcs_writel(HOST_IDTR_BASE, host_idt_base);   /* 22.2.4 */
+	vmcs_writel(HOST_IDTR_BASE, vmx_host_idt_base);   /* 22.2.4 */
 
 	vmcs_writel(HOST_RIP, (unsigned long)vmx_vmexit); /* 22.2.5 */
 
@@ -5065,10 +5065,10 @@ static int handle_exception_nmi(struct kvm_vcpu *vcpu)
 	intr_info = vmx_get_intr_info(vcpu);
 
 	if (is_machine_check(intr_info) || is_nmi(intr_info))
-		return 1; /* handled by handle_exception_nmi_irqoff() */
+		return 1; /* handled by vmx_handle_exception_nmi_irqoff() */
 
 	/*
-	 * Queue the exception here instead of in handle_nm_fault_irqoff().
+	 * Queue the exception here instead of in vmx_handle_nm_fault_irqoff().
 	 * This ensures the nested_vmx check is not skipped so vmexit can
 	 * be reflected to L1 (when it intercepts #NM) before reaching this
 	 * point.
@@ -6741,70 +6741,6 @@ void vmx_load_eoi_exitmap(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)
 	vmcs_write64(EOI_EXIT_BITMAP3, eoi_exit_bitmap[3]);
 }
 
-void vmx_do_interrupt_nmi_irqoff(unsigned long entry);
-
-static void handle_interrupt_nmi_irqoff(struct kvm_vcpu *vcpu,
-					unsigned long entry)
-{
-	bool is_nmi = entry == (unsigned long)asm_exc_nmi_noist;
-
-	kvm_before_interrupt(vcpu, is_nmi ? KVM_HANDLING_NMI : KVM_HANDLING_IRQ);
-	vmx_do_interrupt_nmi_irqoff(entry);
-	kvm_after_interrupt(vcpu);
-}
-
-static void handle_nm_fault_irqoff(struct kvm_vcpu *vcpu)
-{
-	/*
-	 * Save xfd_err to guest_fpu before interrupt is enabled, so the
-	 * MSR value is not clobbered by the host activity before the guest
-	 * has chance to consume it.
-	 *
-	 * Do not blindly read xfd_err here, since this exception might
-	 * be caused by L1 interception on a platform which doesn't
-	 * support xfd at all.
-	 *
-	 * Do it conditionally upon guest_fpu::xfd. xfd_err matters
-	 * only when xfd contains a non-zero value.
-	 *
-	 * Queuing exception is done in vmx_handle_exit. See comment there.
-	 */
-	if (vcpu->arch.guest_fpu.fpstate->xfd)
-		rdmsrl(MSR_IA32_XFD_ERR, vcpu->arch.guest_fpu.xfd_err);
-}
-
-static void handle_exception_nmi_irqoff(struct kvm_vcpu *vcpu, u32 intr_info)
-{
-	const unsigned long nmi_entry = (unsigned long)asm_exc_nmi_noist;
-
-	/* if exit due to PF check for async PF */
-	if (is_page_fault(intr_info))
-		vcpu->arch.apf.host_apf_flags = kvm_read_and_reset_apf_flags();
-	/* if exit due to NM, handle before interrupts are enabled */
-	else if (is_nm_fault(intr_info))
-		handle_nm_fault_irqoff(vcpu);
-	/* Handle machine checks before interrupts are enabled */
-	else if (is_machine_check(intr_info))
-		kvm_machine_check();
-	/* We need to handle NMIs before interrupts are enabled */
-	else if (is_nmi(intr_info))
-		handle_interrupt_nmi_irqoff(vcpu, nmi_entry);
-}
-
-static void handle_external_interrupt_irqoff(struct kvm_vcpu *vcpu,
-					     u32 intr_info)
-{
-	unsigned int vector = intr_info & INTR_INFO_VECTOR_MASK;
-	gate_desc *desc = (gate_desc *)host_idt_base + vector;
-
-	if (KVM_BUG(!is_external_intr(intr_info), vcpu->kvm,
-	    "KVM: unexpected VM-Exit interrupt info: 0x%x", intr_info))
-		return;
-
-	handle_interrupt_nmi_irqoff(vcpu, gate_offset(desc));
-	vcpu->arch.at_instruction_boundary = true;
-}
-
 void vmx_handle_exit_irqoff(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
@@ -6813,9 +6749,10 @@ void vmx_handle_exit_irqoff(struct kvm_vcpu *vcpu)
 		return;
 
 	if (vmx->exit_reason.basic == EXIT_REASON_EXTERNAL_INTERRUPT)
-		handle_external_interrupt_irqoff(vcpu, vmx_get_intr_info(vcpu));
+		vmx_handle_external_interrupt_irqoff(vcpu,
+						     vmx_get_intr_info(vcpu));
 	else if (vmx->exit_reason.basic == EXIT_REASON_EXCEPTION_NMI)
-		handle_exception_nmi_irqoff(vcpu, vmx_get_intr_info(vcpu));
+		vmx_handle_exception_nmi_irqoff(vcpu, vmx_get_intr_info(vcpu));
 }
 
 /*
@@ -8072,7 +8009,7 @@ __init int vmx_hardware_setup(void)
 	int r;
 
 	store_idt(&dt);
-	host_idt_base = dt.address;
+	vmx_host_idt_base = dt.address;
 
 	vmx_setup_user_return_msrs();
 
-- 
2.25.1

