Re: [PATCH] msix: fix msix_set/unset_mask_notifier

[Sridhar Samudrala <sri@us.ibm.com>]

On Wed, 2010-06-02 at 20:49 +0300, Michael S. Tsirkin wrote:
> Sridhar Samudrala reported hitting the following assertions
> in msix.c when doing a guest reboot or live migration using vhost.
> qemu-kvm/hw/msix.c:375: msix_mask_all: Assertion `r >= 0' failed.
> qemu-kvm/hw/msix.c:640: msix_unset_mask_notifier:
> Assertion `dev->msix_mask_notifier_opaque[vector]' failed.
> 
> The issue is that we didn't clear/set the opaque pointer
> when vector is masked. The following patch fixes this.
> 
> Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> 
> Sridhar, could you test the following please?

Yes. looks good and works fine for me.
Tested-by: Sridhar Samudrala <sri@us.ibm.com

> 
>  hw/msix.c |   33 ++++++++++++++++-----------------
>  1 files changed, 16 insertions(+), 17 deletions(-)
> 
> diff --git a/hw/msix.c b/hw/msix.c
> index b400769..24ff6ae 100644
> --- a/hw/msix.c
> +++ b/hw/msix.c
> @@ -610,7 +610,7 @@ void msix_unuse_all_vectors(PCIDevice *dev)
> 
>  int msix_set_mask_notifier(PCIDevice *dev, unsigned vector, void *opaque)
>  {
> -    int r;
> +    int r = 0;
>      if (vector >= dev->msix_entries_nr || !dev->msix_entry_used[vector])
>          return 0;
> 
> @@ -619,13 +619,11 @@ int msix_set_mask_notifier(PCIDevice *dev, unsigned vector, void *opaque)
>      assert(!dev->msix_mask_notifier_opaque[vector]);
> 
>      /* Unmask the new notifier unless vector is masked. */
> -    if (msix_is_masked(dev, vector)) {
> -        return 0;
> -    }
> -    r = dev->msix_mask_notifier(dev, vector, opaque,
> -                                msix_is_masked(dev, vector));
> -    if (r < 0) {
> -        return r;
> +    if (!msix_is_masked(dev, vector)) {
> +        r = dev->msix_mask_notifier(dev, vector, opaque, false);
> +        if (r < 0) {
> +            return r;
> +        }
>      }
>      dev->msix_mask_notifier_opaque[vector] = opaque;
>      return r;
> @@ -634,21 +632,21 @@ int msix_set_mask_notifier(PCIDevice *dev, unsigned vector, void *opaque)
>  int msix_unset_mask_notifier(PCIDevice *dev, unsigned vector)
>  {
>      int r = 0;
> +    void *opaque;
>      if (vector >= dev->msix_entries_nr || !dev->msix_entry_used[vector])
>          return 0;
> 
> +    opaque = dev->msix_mask_notifier_opaque[vector];
> +
>      assert(dev->msix_mask_notifier);
> -    assert(dev->msix_mask_notifier_opaque[vector]);
> +    assert(opaque);
> 
>      /* Mask the old notifier unless it is already masked. */
> -    if (msix_is_masked(dev, vector)) {
> -        return 0;
> -    }
> -    r = dev->msix_mask_notifier(dev, vector,
> -                                dev->msix_mask_notifier_opaque[vector],
> -                                !msix_is_masked(dev, vector));
> -    if (r < 0) {
> -        return r;
> +    if (!msix_is_masked(dev, vector)) {
> +        r = dev->msix_mask_notifier(dev, vector, opaque, true);
> +        if (r < 0) {
> +            return r;
> +        }
>      }
>      dev->msix_mask_notifier_opaque[vector] = NULL;
>      return r;