linux-kernel - [PATCH v4 05/26] KVM: Provide more information in kernel log if hardware enabling fails

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Date:   Thu,  8 Sep 2022 16:25:21 -0700
From:   isaku.yamahata@...el.com
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Marc Zyngier <maz@...nel.org>, Will Deacon <will@...nel.org>,
        Yuan Yao <yuan.yao@...ux.intel.com>
Cc:     isaku.yamahata@...el.com, isaku.yamahata@...il.com,
        Kai Huang <kai.huang@...el.com>, Chao Gao <chao.gao@...el.com>,
        Atish Patra <atishp@...shpatra.org>,
        Shaokun Zhang <zhangshaokun@...ilicon.com>,
        Qi Liu <liuqi115@...wei.com>,
        John Garry <john.garry@...wei.com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Huang Ying <ying.huang@...el.com>,
        Huacai Chen <chenhuacai@...nel.org>,
        Yuan Yao <yuan.yao@...el.com>
Subject: [PATCH v4 05/26] KVM: Provide more information in kernel log if hardware enabling fails

From: Sean Christopherson <seanjc@...gle.com>

Provide the name of the calling function to hardware_enable_nolock() and
include it in the error message to provide additional information on
exactly what path failed.

Opportunistically bump the pr_info() to pr_warn(), failure to enable
virtualization support is warn-worthy as _something_ is wrong with the
system.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
Signed-off-by: Chao Gao <chao.gao@...el.com>
Link: https://lore.kernel.org/r/20220216031528.92558-4-chao.gao@intel.com
Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
Reviewed-by: Yuan Yao <yuan.yao@...el.com>
---
 virt/kvm/kvm_main.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 4243a9541543..278eb6cc7cbe 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -4991,7 +4991,7 @@ static struct miscdevice kvm_dev = {
 	&kvm_chardev_ops,
 };
 
-static void hardware_enable_nolock(void *junk)
+static void hardware_enable_nolock(void *caller_name)
 {
 	int cpu = raw_smp_processor_id();
 	int r;
@@ -5006,7 +5006,8 @@ static void hardware_enable_nolock(void *junk)
 	if (r) {
 		cpumask_clear_cpu(cpu, cpus_hardware_enabled);
 		atomic_inc(&hardware_enable_failed);
-		pr_info("kvm: enabling virtualization on CPU%d failed\n", cpu);
+		pr_warn("kvm: enabling virtualization on CPU%d failed during %s()\n",
+			cpu, (const char *)caller_name);
 	}
 }
 
@@ -5014,7 +5015,7 @@ static int kvm_starting_cpu(unsigned int cpu)
 {
 	raw_spin_lock(&kvm_count_lock);
 	if (kvm_usage_count)
-		hardware_enable_nolock(NULL);
+		hardware_enable_nolock((void *)__func__);
 	raw_spin_unlock(&kvm_count_lock);
 	return 0;
 }
@@ -5063,7 +5064,7 @@ static int hardware_enable_all(void)
 	kvm_usage_count++;
 	if (kvm_usage_count == 1) {
 		atomic_set(&hardware_enable_failed, 0);
-		on_each_cpu(hardware_enable_nolock, NULL, 1);
+		on_each_cpu(hardware_enable_nolock, (void *)__func__, 1);
 
 		if (atomic_read(&hardware_enable_failed)) {
 			hardware_disable_all_nolock();
@@ -5686,7 +5687,7 @@ static void kvm_resume(void)
 {
 	if (kvm_usage_count) {
 		lockdep_assert_not_held(&kvm_count_lock);
-		hardware_enable_nolock(NULL);
+		hardware_enable_nolock((void *)__func__);
 	}
 }
 
-- 
2.25.1