On 2015/3/27 9:31, Marcelo Tosatti wrote:
On Wed, Mar 25, 2015 at 05:09:13PM +0000, Marc Zyngier wrote:
On 23/03/15 15:58, Andre Przywara wrote:
In kvm_destroy_vm() we call kvm_io_bus_destroy() pretty early,
especially before calling kvm_arch_destroy_vm(). To avoid
unregistering devices from the already destroyed bus, let's mark
the bus with NULL to let other users know it has been destroyed
already.
This avoids a crash on a VM shutdown with the VGIC using the
kvm_io_bus later (the unregistering is in there to be able to roll
back a faulting init).
Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
That seems sensible, but I don't see why nobody else hits that. What are
we doing differently?
Otherwise,
Reviewed-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Paolo, Marcelo, can we have your Ack on this?
Thanks,
M.
---
virt/kvm/kvm_main.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 8c7ab0b..6f164eb 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -604,8 +604,10 @@ static void kvm_destroy_vm(struct kvm *kvm)
list_del(&kvm->vm_list);
spin_unlock(&kvm_lock);
kvm_free_irq_routing(kvm);
- for (i = 0; i < KVM_NR_BUSES; i++)
+ for (i = 0; i < KVM_NR_BUSES; i++) {
kvm_io_bus_destroy(kvm->buses[i]);
+ kvm->buses[i] = NULL;
Could we fold this line into a common like,
@@ -596,7 +597,6 @@ static void kvm_destroy_devices(struct kvm *kvm)
static void kvm_destroy_vm(struct kvm *kvm)
{
- int i;
struct mm_struct *mm = kvm->mm;
kvm_arch_sync_events(kvm);
@@ -604,8 +604,7 @@ static void kvm_destroy_vm(struct kvm *kvm)
list_del(&kvm->vm_list);
spin_unlock(&kvm_lock);
kvm_free_irq_routing(kvm);
- for (i = 0; i < KVM_NR_BUSES; i++)
- kvm_io_bus_destroy(kvm->buses[i]);
+ kvm_destroy_all_io_bus(kvm);
kvm_coalesced_mmio_free(kvm);
#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
mmu_notifier_unregister(&kvm->mmu_notifier, kvm->mm);
@@ -2943,6 +2942,16 @@ static void kvm_io_bus_destroy(struct kvm_io_bus
*bus)
kfree(bus);
}
+static void kvm_destroy_all_io_bus(struct kvm *kvm)
+{
+ int i;
+
+ for (i = 0; i < KVM_NR_BUSES; i++) {
+ kvm_io_bus_destroy(kvm->buses[i]);
+ kvm->buses[i] = NULL;
+ }
+}
+
static inline int kvm_io_bus_cmp(const struct kvm_io_range *r1,
const struct kvm_io_range *r2)
{
Thanks
Tiejun
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