[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-ppc] [PATCH 5/5] spapr: Use unplug_request for PCI hot unplug
From: |
David Gibson |
Subject: |
Re: [Qemu-ppc] [PATCH 5/5] spapr: Use unplug_request for PCI hot unplug |
Date: |
Mon, 3 Jul 2017 16:35:15 +1000 |
User-agent: |
Mutt/1.8.0 (2017-02-23) |
On Wed, Jun 21, 2017 at 11:50:08AM +0200, Greg Kurz wrote:
> On Tue, 20 Jun 2017 09:53:32 +0800
> David Gibson <address@hidden> wrote:
>
> > AIUI, ->unplug_request in the HotplugHandler is used for "soft"
> > unplug, where acknowledgement from the guest is required before
> > completing the unplug, whereas ->unplug is used for "hard" unplug
> > where qemu unilaterally removes the device, and the guest just has to
> > cope with its sudden absence. For spapr we (correctly) use
> > ->unplug_request for CPU and memory hot unplug but we use ->unplug for
> > PCI.
> >
> > While I think it might be possible to support "hard" PCI unplug within
> > the PAPR model, that's not how it actually works now. Although it's
> > called from ->unplug, the PCI unplug path will usually just mark the
> > device for removal, with completion of the unplug delayed until
> > userspace responds to the unplug notification. If the guest doesn't
> > respond as expected, that could delay the unplug completiong
> > arbitrarily long.
> >
> > To reflect that, change the PCI unplug path to be called from
> > ->unplug_request.
> >
> > Signed-off-by: David Gibson <address@hidden>
> > ---
> > hw/ppc/spapr_pci.c | 7 ++++---
> > 1 file changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
> > index f2543ef..bda8938 100644
> > --- a/hw/ppc/spapr_pci.c
> > +++ b/hw/ppc/spapr_pci.c
> > @@ -1469,8 +1469,8 @@ out:
> > }
> > }
> >
> > -static void spapr_phb_hot_unplug_child(HotplugHandler *plug_handler,
> > - DeviceState *plugged_dev, Error
> > **errp)
> > +static void spapr_pci_unplug_request(HotplugHandler *plug_handler,
> > + DeviceState *plugged_dev, Error
> > **errp)
> > {
> > sPAPRPHBState *phb = SPAPR_PCI_HOST_BRIDGE(DEVICE(plug_handler));
> > PCIDevice *pdev = PCI_DEVICE(plugged_dev);
> > @@ -1485,6 +1485,7 @@ static void spapr_phb_hot_unplug_child(HotplugHandler
> > *plug_handler,
> > }
> >
> > g_assert(drc);
> > + g_assert(drc->dev == plugged_dev);
> >
> > drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
> > if (!drck->release_pending(drc)) {
> > @@ -1973,7 +1974,7 @@ static void spapr_phb_class_init(ObjectClass *klass,
> > void *data)
> > dc->user_creatable = true;
> > set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories);
> > hp->plug = spapr_phb_hot_plug_child;
>
> Maybe you can rename spapr_phb_hot_plug_child() to spapr_pci_plug() for
> consistency ?
Good idea. I've made that change.
>
> Anyway,
>
> Reviewed-by: Greg Kurz <address@hidden>
>
> > - hp->unplug = spapr_phb_hot_unplug_child;
> > + hp->unplug_request = spapr_pci_unplug_request;
> > }
> >
> > static const TypeInfo spapr_phb_info = {
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
signature.asc
Description: PGP signature
[Prev in Thread] |
Current Thread |
[Next in Thread] |
- Re: [Qemu-ppc] [PATCH 5/5] spapr: Use unplug_request for PCI hot unplug,
David Gibson <=