KVM hypercalls return a negative value error code in case of a fatal
error, e.g. when the hypercall isn't supported or was made with invalid
parameters. WARN_ONCE on fatal errors when sending PV IPIs as any such
error all but guarantees an SMP system will hang due to a missing IPI.
Fixes: aaffcfd1e82d ("KVM: X86: Implement PV IPIs in linux guest")
Cc: stable@xxxxxxxxxxxxxxx
Cc: Wanpeng Li <wanpengli@xxxxxxxxxxx>
Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
---
arch/x86/kernel/kvm.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index ba4bfb7f6a36..5c93a65ee1e5 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -457,6 +457,7 @@ static void __send_ipi_mask(const struct cpumask *mask, int vector)
#else
u64 ipi_bitmap = 0;
#endif
+ long ret;
if (cpumask_empty(mask))
return;
@@ -482,8 +483,9 @@ static void __send_ipi_mask(const struct cpumask *mask, int vector)
} else if (apic_id < min + KVM_IPI_CLUSTER_SIZE) {
max = apic_id < max ? max : apic_id;
} else {
- kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,
+ ret = kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,
(unsigned long)(ipi_bitmap >> BITS_PER_LONG), min, icr);
+ WARN_ONCE(ret < 0, "KVM: failed to send PV IPI: %ld", ret);
min = max = apic_id;
ipi_bitmap = 0;
}
@@ -491,8 +493,9 @@ static void __send_ipi_mask(const struct cpumask *mask, int vector)
}
if (ipi_bitmap) {
- kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,
+ ret = kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,
(unsigned long)(ipi_bitmap >> BITS_PER_LONG), min, icr);
+ WARN_ONCE(ret < 0, "KVM: failed to send PV IPI: %ld", ret);
}
local_irq_restore(flags);
--
2.20.1
