[PATCH 5.16 09/28] KVM: x86: dont print when fail to read/write pv eoi memory

From: Greg Kroah-Hartman
Date: Tue Jan 18 2022 - 11:13:49 EST


From: Li RongQing <lirongqing@xxxxxxxxx>

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@xxxxxxxxxx>
Reviewed-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Signed-off-by: Li RongQing <lirongqing@xxxxxxxxx>
Cc: stable@xxxxxxxxxx
Message-Id: <1636026974-50555-1-git-send-email-lirongqing@xxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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);
}