[PATCH] KVM: x86: Ratelimit all I/O APIC and local APIC kernel log messages

[PATCH] KVM: x86: Ratelimit all I/O APIC and local APIC kernel log messages

[Sean Christopherson]

From: Amirmohammad Eftekhar <amirmohammad.eftekhar@cispa.de>

Ratelimit all of the kernel messages in the APIC code, as every single one
can be triggered at will by the guest.

Opportunistically use the more modern APIs so that the messages are run
through pr_fmt(), i.e. get prefixed with KVM's name and info.

Fixes: 1fd4f2a5ed8f ("KVM: In-kernel I/O APIC model")
Fixes: 8f423a80d299 ("KVM: SVM: Support MMIO for an SEV-ES guest")
Cc: Chris Mason <mason@kernel.org>
Signed-off-by: Amirmohammad Eftekhar <amirmohammad.eftekhar@cispa.de>
Co-developed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
[sean: smush everything into one patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/ioapic.c | 4 ++--
 arch/x86/kvm/lapic.c  | 8 ++++----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/ioapic.c b/arch/x86/kvm/ioapic.c
index 0d59b9c758c2..df15d940181c 100644
--- a/arch/x86/kvm/ioapic.c
+++ b/arch/x86/kvm/ioapic.c
@@ -647,7 +647,7 @@ static int ioapic_mmio_read(struct kvm_vcpu *vcpu, struct kvm_io_device *this,
 		memcpy(val, (char *)&result, len);
 		break;
 	default:
-		printk(KERN_WARNING "ioapic: wrong length %d\n", len);
+		pr_warn_ratelimited("ioapic: wrong length %d\n", len);
 	}
 	return 0;
 }
@@ -672,7 +672,7 @@ static int ioapic_mmio_write(struct kvm_vcpu *vcpu, struct kvm_io_device *this,
 		data = *(u8  *) val;
 		break;
 	default:
-		printk(KERN_WARNING "ioapic: Unsupported size %d\n", len);
+		pr_warn_ratelimited("ioapic: Unsupported size %d\n", len);
 		return 0;
 	}
 
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index ecf611845fb1..a49bb38b4f70 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1123,7 +1123,7 @@ static void kvm_apic_disabled_lapic_found(struct kvm *kvm)
 {
 	if (!kvm->arch.disabled_lapic_found) {
 		kvm->arch.disabled_lapic_found = true;
-		pr_info("Disabled LAPIC found during irq injection\n");
+		pr_info_ratelimited("Disabled LAPIC found during irq injection\n");
 	}
 }
 
@@ -1359,7 +1359,7 @@ int __kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
 
 	if (irq->dest_mode == APIC_DEST_PHYSICAL &&
 	    irq->dest_id == 0xff && kvm_lowest_prio_delivery(irq)) {
-		pr_info("apic: phys broadcast and lowest prio\n");
+		pr_info_ratelimited("apic: phys broadcast and lowest prio\n");
 		irq->delivery_mode = APIC_DM_FIXED;
 	}
 
@@ -1826,8 +1826,8 @@ static int kvm_lapic_reg_read(struct kvm_lapic *apic, u32 offset, int len,
 		memcpy(data, (char *)&result + alignment, len);
 		break;
 	default:
-		printk(KERN_ERR "Local APIC read with len = %x, "
-		       "should be 1,2, or 4 instead\n", len);
+		pr_err_ratelimited("Local APIC read with len = %x, should be 1,2, or 4 instead\n",
+				   len);
 		break;
 	}
 	return 0;

base-commit: 164405e8e9a0378c7e1aff2254625a6553a291f1
-- 
2.56.0.257.gf7497c7d27-goog