linux-kernel - [PATCH] x86/SVM: Fix implicit declaration issue for __default_cpu_present_to

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Date:	Mon, 13 Jun 2016 15:28:06 -0500
From:	Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>
To:	<pbonzini@...hat.com>, <rkrcmar@...hat.com>
CC:	<fengguang.wu@...el.com>, <kvm@...r.kernel.org>,
	<kbuild-all@...org>, <linux-kernel@...r.kernel.org>,
	Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>,
	Suravee Suthikulpanit <suravee.suthikulpanit@....com>
Subject: [PATCH] x86/SVM: Fix implicit declaration issue for __default_cpu_present_to_apicid()

The commit 8221c1370056 ("svm: Manage vcpu load/unload when enable AVIC")
introduces a build error due to implicit function declaration
with#ifdef CONFIG_X86_32 and #ifndef CONFIG_X86_LOCAL_APIC.
with Kbuild test robot config file (i386-randconfig-x0-06121009).

This patch fixes the issue by using the default_cpu_present_to_apicid(),
adding necessary function declaration, and exporting the symbol.

Reported-by: kbuild test robot <fengguang.wu@...el.com>
Fixes: commit 8221c1370056 ("svm: Manage vcpu load/unload when enable AVIC")
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
---
 arch/x86/include/asm/apic.h | 5 +++++
 arch/x86/kernel/setup.c     | 1 +
 arch/x86/kvm/svm.c          | 6 +++---
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index bc27611..beb1d4a 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -631,6 +631,11 @@ extern int default_cpu_present_to_apicid(int mps_cpu);
 extern int default_check_phys_apicid_present(int phys_apicid);
 #endif
 
+#else /* CONFIG_X86_LOCAL_APIC */
+static inline int default_cpu_present_to_apicid(int mps_cpu)
+{
+	return BAD_APICID;
+}
 #endif /* CONFIG_X86_LOCAL_APIC */
 extern void irq_enter(void);
 extern void irq_exit(void);
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index c4e7b39..90168be 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -137,6 +137,7 @@ int default_cpu_present_to_apicid(int mps_cpu)
 {
 	return __default_cpu_present_to_apicid(mps_cpu);
 }
+EXPORT_SYMBOL_GPL(default_cpu_present_to_apicid);
 
 int default_check_phys_apicid_present(int phys_apicid)
 {
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 5b12438..803351a 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1402,7 +1402,7 @@ avic_update_iommu(struct kvm_vcpu *vcpu, int cpu, phys_addr_t pa, bool r)
 static void avic_set_running(struct kvm_vcpu *vcpu, bool is_run)
 {
 	u64 entry;
-	int h_physical_id = __default_cpu_present_to_apicid(vcpu->cpu);
+	int h_physical_id = default_cpu_present_to_apicid(vcpu->cpu);
 	struct vcpu_svm *svm = to_svm(vcpu);
 
 	if (!kvm_vcpu_apicv_active(vcpu))
@@ -1434,7 +1434,7 @@ static void avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 {
 	u64 entry;
 	/* ID = 0xff (broadcast), ID > 0xff (reserved) */
-	int h_physical_id = __default_cpu_present_to_apicid(cpu);
+	int h_physical_id = default_cpu_present_to_apicid(cpu);
 	struct vcpu_svm *svm = to_svm(vcpu);
 
 	if (!kvm_vcpu_apicv_active(vcpu))
@@ -4328,7 +4328,7 @@ static void svm_deliver_avic_intr(struct kvm_vcpu *vcpu, int vec)
 
 	if (avic_vcpu_is_running(vcpu))
 		wrmsrl(SVM_AVIC_DOORBELL,
-		       __default_cpu_present_to_apicid(vcpu->cpu));
+		       default_cpu_present_to_apicid(vcpu->cpu));
 	else
 		kvm_vcpu_wake_up(vcpu);
 }
-- 
1.9.1