KVM: i8254: don't assume layout of kvm_kpit_state

channels has offset 0 and correct size now, but that can change.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 76f9f48898a545b1ce539c115b076fd46651ec92..60d6c0036a98287eb0b2ac56106a4a027c70363d 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3604,9 +3604,13 @@ static int kvm_vm_ioctl_set_irqchip(struct kvm *kvm, struct kvm_irqchip *chip)
 
 static int kvm_vm_ioctl_get_pit(struct kvm *kvm, struct kvm_pit_state *ps)
 {
-       mutex_lock(&kvm->arch.vpit->pit_state.lock);
-       memcpy(ps, &kvm->arch.vpit->pit_state, sizeof(struct kvm_pit_state));
-       mutex_unlock(&kvm->arch.vpit->pit_state.lock);
+       struct kvm_kpit_state *kps = &kvm->arch.vpit->pit_state;
+
+       BUILD_BUG_ON(sizeof(*ps) != sizeof(kps->channels));
+
+       mutex_lock(&kps->lock);
+       memcpy(ps, &kps->channels, sizeof(*ps));
+       mutex_unlock(&kps->lock);
        return 0;
 }
 
@@ -3616,7 +3620,7 @@ static int kvm_vm_ioctl_set_pit(struct kvm *kvm, struct kvm_pit_state *ps)
        struct kvm_pit *pit = kvm->arch.vpit;
 
        mutex_lock(&pit->pit_state.lock);
-       memcpy(&pit->pit_state, ps, sizeof(struct kvm_pit_state));
+       memcpy(&pit->pit_state.channels, ps, sizeof(*ps));
        for (i = 0; i < 3; i++)
                kvm_pit_load_count(pit, i, ps->channels[i].count, 0);
        mutex_unlock(&pit->pit_state.lock);