On 3/9/22 09:35, Li RongQing wrote:
if apic_id is less than min, and (max - apic_id) is greater than
KVM_IPI_CLUSTER_SIZE, then third check condition is satisfied,
but it should enter last branch, send IPI directly
Fixes: aaffcfd1e82 ("KVM: X86: Implement PV IPIs in linux guest")
Signed-off-by: Li RongQing <lirongqing@xxxxxxxxx>
So an example is
apic_id on first iteration = 1
apic_id on second iteration = KVM_IPI_CLUSTER_SIZE
apic_id on third iteration = 0
Thanks, this looks good.
Paolo
---
arch/x86/kernel/kvm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 959f919..8915c93 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -517,7 +517,7 @@ static void __send_ipi_mask(const struct cpumask *mask, int vector)
} else if (apic_id < min && max - apic_id < KVM_IPI_CLUSTER_SIZE) {
ipi_bitmap <<= min - apic_id;
min = apic_id;
- } else if (apic_id < min + KVM_IPI_CLUSTER_SIZE) {
+ } else if (apic_id > min && apic_id < min + KVM_IPI_CLUSTER_SIZE) {
max = apic_id < max ? max : apic_id;
} else {
ret = kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,
