From: Zenghui Yu yuzenghui@huawei.com
commit ca185b260951d3b55108c0b95e188682d8a507b7 upstream.
It's possible that two LPIs locate in the same "byte_offset" but target two different vcpus, where their pending status are indicated by two different pending tables. In such a scenario, using last_byte_offset optimization will lead KVM relying on the wrong pending table entry. Let us use last_ptr instead, which can be treated as a byte index into a pending table and also, can be vcpu specific.
Fixes: 280771252c1b ("KVM: arm64: vgic-v3: KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES") Cc: stable@vger.kernel.org Signed-off-by: Zenghui Yu yuzenghui@huawei.com Signed-off-by: Marc Zyngier maz@kernel.org Acked-by: Eric Auger eric.auger@redhat.com Link: https://lore.kernel.org/r/20191029071919.177-4-yuzenghui@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- virt/kvm/arm/vgic/vgic-v3.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/virt/kvm/arm/vgic/vgic-v3.c +++ b/virt/kvm/arm/vgic/vgic-v3.c @@ -331,8 +331,8 @@ retry: int vgic_v3_save_pending_tables(struct kvm *kvm) { struct vgic_dist *dist = &kvm->arch.vgic; - int last_byte_offset = -1; struct vgic_irq *irq; + gpa_t last_ptr = ~(gpa_t)0; int ret; u8 val;
@@ -352,11 +352,11 @@ int vgic_v3_save_pending_tables(struct k bit_nr = irq->intid % BITS_PER_BYTE; ptr = pendbase + byte_offset;
- if (byte_offset != last_byte_offset) { + if (ptr != last_ptr) { ret = kvm_read_guest_lock(kvm, ptr, &val, 1); if (ret) return ret; - last_byte_offset = byte_offset; + last_ptr = ptr; }
stored = val & (1U << bit_nr);