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| author | Li RongQing <lirongqing@baidu.com> | 2022-03-09 16:35:44 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-15 14:18:27 +0200 |
| commit | 4c277c846a21e5be8afc5f75b33d2d546502458f (patch) | |
| tree | 7f92a124022f4b0d810c523434a19c06af0bd439 /arch/x86 | |
| parent | a1c03f11cc3c703fa39691d2dab98a5f5543326c (diff) | |
KVM: x86: fix sending PV IPI
commit c15e0ae42c8e5a61e9aca8aac920517cf7b3e94e upstream.
If apic_id is less than min, and (max - apic_id) is greater than
KVM_IPI_CLUSTER_SIZE, then the third check condition is satisfied but
the new apic_id does not fit the bitmask. In this case __send_ipi_mask
should send the IPI.
This is mostly theoretical, but it can happen if the apic_ids on three
iterations of the loop are for example 1, KVM_IPI_CLUSTER_SIZE, 0.
Fixes: aaffcfd1e82 ("KVM: X86: Implement PV IPIs in linux guest")
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Message-Id: <1646814944-51801-1-git-send-email-lirongqing@baidu.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/kvm.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 6ff2c7cac4c4..408b51aba293 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -487,7 +487,7 @@ 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, |