[PATCH v2 2/6] KVM/x86: Return -errno instead of "1" for APIC related MSR emulation
From: Juergen Gross
Date: Thu May 28 2026 - 07:37:08 EST
Instead of a literal "1" for signalling an error, use a negative errno
value in the emulation code of APIC related MSR registers.
Remove some not needed braces.
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
V2:
- use -errno instead of KVM_MSR_RET_ERR
---
arch/x86/kvm/lapic.c | 39 +++++++++++++++++++--------------------
1 file changed, 19 insertions(+), 20 deletions(-)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 4078e624ca66..3e7d83db2f7a 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2412,11 +2412,10 @@ static int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
switch (reg) {
case APIC_ID: /* Local APIC ID */
- if (!apic_x2apic_mode(apic)) {
+ if (!apic_x2apic_mode(apic))
kvm_apic_set_xapic_id(apic, val >> 24);
- } else {
- ret = 1;
- }
+ else
+ ret = -EINVAL;
break;
case APIC_TASKPRI:
@@ -2432,14 +2431,14 @@ static int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
if (!apic_x2apic_mode(apic))
kvm_apic_set_ldr(apic, val & APIC_LDR_MASK);
else
- ret = 1;
+ ret = -EINVAL;
break;
case APIC_DFR:
if (!apic_x2apic_mode(apic))
kvm_apic_set_dfr(apic, val | 0x0FFFFFFF);
else
- ret = 1;
+ ret = -EINVAL;
break;
case APIC_SPIV: {
@@ -2470,7 +2469,7 @@ static int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
break;
case APIC_ICR2:
if (apic_x2apic_mode(apic))
- ret = 1;
+ ret = -EINVAL;
else
kvm_lapic_set_reg(apic, APIC_ICR2, val & 0xff000000);
break;
@@ -2485,7 +2484,7 @@ static int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
case APIC_LVTCMCI: {
u32 index = get_lvt_index(reg);
if (!kvm_lapic_lvt_supported(apic, index)) {
- ret = 1;
+ ret = -EINVAL;
break;
}
if (!kvm_apic_sw_enabled(apic))
@@ -2527,7 +2526,7 @@ static int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
}
case APIC_ESR:
if (apic_x2apic_mode(apic) && val != 0)
- ret = 1;
+ ret = -EINVAL;
break;
case APIC_SELF_IPI:
@@ -2536,12 +2535,12 @@ static int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
* the vector, everything else is reserved.
*/
if (!apic_x2apic_mode(apic) || (val & ~APIC_VECTOR_MASK))
- ret = 1;
+ ret = -EINVAL;
else
kvm_apic_send_ipi(apic, APIC_DEST_SELF | val, 0);
break;
default:
- ret = 1;
+ ret = -EINVAL;
break;
}
@@ -2599,7 +2598,7 @@ EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_lapic_set_eoi);
static int __kvm_x2apic_icr_write(struct kvm_lapic *apic, u64 data, bool fast)
{
if (data & X2APIC_ICR_RESERVED_BITS)
- return 1;
+ return -EINVAL;
/*
* The BUSY bit is reserved on both Intel and AMD in x2APIC mode, but
@@ -2804,12 +2803,12 @@ int kvm_apic_set_base(struct kvm_vcpu *vcpu, u64 value, bool host_initiated)
(guest_cpu_cap_has(vcpu, X86_FEATURE_X2APIC) ? 0 : X2APIC_ENABLE);
if ((value & reserved_bits) != 0 || new_mode == LAPIC_MODE_INVALID)
- return 1;
+ return -EINVAL;
if (!host_initiated) {
if (old_mode == LAPIC_MODE_X2APIC && new_mode == LAPIC_MODE_XAPIC)
return 1;
if (old_mode == LAPIC_MODE_DISABLED && new_mode == LAPIC_MODE_X2APIC)
- return 1;
+ return -EINVAL;
}
__kvm_apic_set_base(vcpu, value);
@@ -3438,7 +3437,7 @@ static int kvm_lapic_msr_read(struct kvm_lapic *apic, u32 reg, u64 *data)
}
if (kvm_lapic_reg_read(apic, reg, 4, &low))
- return 1;
+ return -EINVAL;
*data = low;
@@ -3457,7 +3456,7 @@ static int kvm_lapic_msr_write(struct kvm_lapic *apic, u32 reg, u64 data)
/* Bits 63:32 are reserved in all other registers. */
if (data >> 32)
- return 1;
+ return -EINVAL;
return kvm_lapic_reg_write(apic, reg, (u32)data);
}
@@ -3468,7 +3467,7 @@ int kvm_x2apic_msr_write(struct kvm_vcpu *vcpu, u32 msr, u64 data)
u32 reg = (msr - APIC_BASE_MSR) << 4;
if (!lapic_in_kernel(vcpu) || !apic_x2apic_mode(apic))
- return 1;
+ return -EINVAL;
return kvm_lapic_msr_write(apic, reg, data);
}
@@ -3479,7 +3478,7 @@ int kvm_x2apic_msr_read(struct kvm_vcpu *vcpu, u32 msr, u64 *data)
u32 reg = (msr - APIC_BASE_MSR) << 4;
if (!lapic_in_kernel(vcpu) || !apic_x2apic_mode(apic))
- return 1;
+ return -EINVAL;
return kvm_lapic_msr_read(apic, reg, data);
}
@@ -3487,7 +3486,7 @@ int kvm_x2apic_msr_read(struct kvm_vcpu *vcpu, u32 msr, u64 *data)
int kvm_hv_vapic_msr_write(struct kvm_vcpu *vcpu, u32 reg, u64 data)
{
if (!lapic_in_kernel(vcpu))
- return 1;
+ return -EINVAL;
return kvm_lapic_msr_write(vcpu->arch.apic, reg, data);
}
@@ -3495,7 +3494,7 @@ int kvm_hv_vapic_msr_write(struct kvm_vcpu *vcpu, u32 reg, u64 data)
int kvm_hv_vapic_msr_read(struct kvm_vcpu *vcpu, u32 reg, u64 *data)
{
if (!lapic_in_kernel(vcpu))
- return 1;
+ return -EINVAL;
return kvm_lapic_msr_read(vcpu->arch.apic, reg, data);
}
--
2.54.0