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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>,
        David Matlack <dmatlack@google.com>
Subject: [PATCH v10 104/108] KVM: TDX: Silently ignore INIT/SIPI
Date:   Sat, 29 Oct 2022 23:23:45 -0700
Message-Id: <a888bb4d30de2e57b0eb5e61189349c86cab1a70.1667110240.git.isaku.yamahata@intel.com>
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References: <cover.1667110240.git.isaku.yamahata@intel.com>
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From: Isaku Yamahata <isaku.yamahata@intel.com>

The TDX module API doesn't provide API for VMM to inject INIT IPI and SIPI.
Instead it defines the different protocols to boot application processors.
Ignore INIT and SIPI events for the TDX guest.

There are two options. 1) (silently) ignore INIT/SIPI request or 2) return
error to guest TDs somehow.  Given that TDX guest is paravirtualized to
boot AP, the option 1 is chosen for simplicity.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
---
 arch/x86/include/asm/kvm-x86-ops.h |  1 +
 arch/x86/include/asm/kvm_host.h    |  2 ++
 arch/x86/kvm/lapic.c               | 19 ++++++++++++-------
 arch/x86/kvm/svm/svm.c             |  1 +
 arch/x86/kvm/vmx/main.c            | 22 +++++++++++++++++++++-
 5 files changed, 37 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 17c3828d42a3..4e9b96480716 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -140,6 +140,7 @@ KVM_X86_OP_OPTIONAL(migrate_timers)
 KVM_X86_OP(msr_filter_changed)
 KVM_X86_OP(complete_emulated_msr)
 KVM_X86_OP(vcpu_deliver_sipi_vector)
+KVM_X86_OP(vcpu_deliver_init)
 KVM_X86_OP_OPTIONAL_RET0(vcpu_get_apicv_inhibit_reasons);
 KVM_X86_OP(check_processor_compatibility)
 
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 094fff5414e1..df67ca7b23d3 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1706,6 +1706,7 @@ struct kvm_x86_ops {
 	int (*complete_emulated_msr)(struct kvm_vcpu *vcpu, int err);
 
 	void (*vcpu_deliver_sipi_vector)(struct kvm_vcpu *vcpu, u8 vector);
+	void (*vcpu_deliver_init)(struct kvm_vcpu *vcpu);
 
 	/*
 	 * Returns vCPU specific APICv inhibit reasons
@@ -1914,6 +1915,7 @@ int kvm_emulate_wbinvd(struct kvm_vcpu *vcpu);
 void kvm_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg);
 int kvm_load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector, int seg);
 void kvm_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector);
+void kvm_vcpu_deliver_init(struct kvm_vcpu *vcpu);
 
 int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int idt_index,
 		    int reason, bool has_error_code, u32 error_code);
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 7a1d612bd138..7393d858ed72 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -3035,6 +3035,16 @@ int kvm_lapic_set_pv_eoi(struct kvm_vcpu *vcpu, u64 data, unsigned long len)
 	return 0;
 }
 
+void kvm_vcpu_deliver_init(struct kvm_vcpu *vcpu)
+{
+	kvm_vcpu_reset(vcpu, true);
+	if (kvm_vcpu_is_bsp(vcpu))
+		vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
+	else
+		vcpu->arch.mp_state = KVM_MP_STATE_INIT_RECEIVED;
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_deliver_init);
+
 int kvm_apic_accept_events(struct kvm_vcpu *vcpu)
 {
 	struct kvm_lapic *apic = vcpu->arch.apic;
@@ -3066,13 +3076,8 @@ int kvm_apic_accept_events(struct kvm_vcpu *vcpu)
 		return 0;
 	}
 
-	if (test_and_clear_bit(KVM_APIC_INIT, &apic->pending_events)) {
-		kvm_vcpu_reset(vcpu, true);
-		if (kvm_vcpu_is_bsp(apic->vcpu))
-			vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
-		else
-			vcpu->arch.mp_state = KVM_MP_STATE_INIT_RECEIVED;
-	}
+	if (test_and_clear_bit(KVM_APIC_INIT, &apic->pending_events))
+		static_call(kvm_x86_vcpu_deliver_init)(vcpu);
 	if (test_and_clear_bit(KVM_APIC_SIPI, &apic->pending_events)) {
 		if (vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED) {
 			/* evaluate pending_events before reading the vector */
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 2bcf2e1a5271..5d56b0f1f595 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4857,6 +4857,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.complete_emulated_msr = svm_complete_emulated_msr,
 
 	.vcpu_deliver_sipi_vector = svm_vcpu_deliver_sipi_vector,
+	.vcpu_deliver_init = kvm_vcpu_deliver_init,
 	.vcpu_get_apicv_inhibit_reasons = avic_vcpu_get_apicv_inhibit_reasons,
 };
 
diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index 4acba8d8cb27..d776d5d169d0 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -286,6 +286,25 @@ static void vt_deliver_interrupt(struct kvm_lapic *apic, int delivery_mode,
 	vmx_deliver_interrupt(apic, delivery_mode, trig_mode, vector);
 }
 
+static void vt_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector)
+{
+	if (is_td_vcpu(vcpu))
+		return;
+
+	kvm_vcpu_deliver_sipi_vector(vcpu, vector);
+}
+
+static void vt_vcpu_deliver_init(struct kvm_vcpu *vcpu)
+{
+	if (is_td_vcpu(vcpu)) {
+		/* TDX doesn't support INIT.  Ignore INIT event */
+		vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
+		return;
+	}
+
+	kvm_vcpu_deliver_init(vcpu);
+}
+
 static void vt_flush_tlb_all(struct kvm_vcpu *vcpu)
 {
 	if (is_td_vcpu(vcpu))
@@ -627,7 +646,8 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
 	.msr_filter_changed = vmx_msr_filter_changed,
 	.complete_emulated_msr = kvm_complete_insn_gp,
 
-	.vcpu_deliver_sipi_vector = kvm_vcpu_deliver_sipi_vector,
+	.vcpu_deliver_sipi_vector = vt_vcpu_deliver_sipi_vector,
+	.vcpu_deliver_init = vt_vcpu_deliver_init,
 
 	.dev_mem_enc_ioctl = tdx_dev_ioctl,
 	.mem_enc_ioctl = vt_mem_enc_ioctl,
-- 
2.25.1