linux-kernel - [PATCH 5.15 09/28] KVM: x86: dont print when fail to read/write pv eoi memory

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Date:   Tue, 18 Jan 2022 17:05:55 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Vitaly Kuznetsov <vkuznets@...hat.com>,
        Li RongQing <lirongqing@...du.com>, stable@...nel.org,
        Paolo Bonzini <pbonzini@...hat.com>
Subject: [PATCH 5.15 09/28] KVM: x86: dont print when fail to read/write pv eoi memory

From: Li RongQing <lirongqing@...du.com>

commit ce5977b181c1613072eafbc7546bcb6c463ea68c upstream.

If guest gives MSR_KVM_PV_EOI_EN a wrong value, this printk() will
be trigged, and kernel log is spammed with the useless message

Fixes: 0d88800d5472 ("kvm: x86: ioapic and apic debug macros cleanup")
Reported-by: Vitaly Kuznetsov <vkuznets@...hat.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@...hat.com>
Signed-off-by: Li RongQing <lirongqing@...du.com>
Cc: stable@...nel.org
Message-Id: <1636026974-50555-1-git-send-email-lirongqing@...du.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/x86/kvm/lapic.c |   18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -676,31 +676,25 @@ static inline bool pv_eoi_enabled(struct
 static bool pv_eoi_get_pending(struct kvm_vcpu *vcpu)
 {
 	u8 val;
-	if (pv_eoi_get_user(vcpu, &val) < 0) {
-		printk(KERN_WARNING "Can't read EOI MSR value: 0x%llx\n",
-			   (unsigned long long)vcpu->arch.pv_eoi.msr_val);
+	if (pv_eoi_get_user(vcpu, &val) < 0)
 		return false;
-	}
+
 	return val & KVM_PV_EOI_ENABLED;
 }
 
 static void pv_eoi_set_pending(struct kvm_vcpu *vcpu)
 {
-	if (pv_eoi_put_user(vcpu, KVM_PV_EOI_ENABLED) < 0) {
-		printk(KERN_WARNING "Can't set EOI MSR value: 0x%llx\n",
-			   (unsigned long long)vcpu->arch.pv_eoi.msr_val);
+	if (pv_eoi_put_user(vcpu, KVM_PV_EOI_ENABLED) < 0)
 		return;
-	}
+
 	__set_bit(KVM_APIC_PV_EOI_PENDING, &vcpu->arch.apic_attention);
 }
 
 static void pv_eoi_clr_pending(struct kvm_vcpu *vcpu)
 {
-	if (pv_eoi_put_user(vcpu, KVM_PV_EOI_DISABLED) < 0) {
-		printk(KERN_WARNING "Can't clear EOI MSR value: 0x%llx\n",
-			   (unsigned long long)vcpu->arch.pv_eoi.msr_val);
+	if (pv_eoi_put_user(vcpu, KVM_PV_EOI_DISABLED) < 0)
 		return;
-	}
+
 	__clear_bit(KVM_APIC_PV_EOI_PENDING, &vcpu->arch.apic_attention);
 }