From: Igor Mammedov <imammedo@redhat.com>
To: Maxim Levitsky <mlevitsk@redhat.com>
Cc: Julia Suvorova <jusual@redhat.com>,
qemu-devel@nongnu.org, "Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [PATCH 1/1] pci/pcie: refuse another hotplug/unplug event if attention button is pending
Date: Thu, 30 Jul 2020 13:38:53 +0200 [thread overview]
Message-ID: <20200730133853.048b64ce@redhat.com> (raw)
In-Reply-To: <1111d100381f431c1ffeabf1f2c7c74ba79a2af5.camel@redhat.com>
On Wed, 29 Jul 2020 08:09:37 +0300
Maxim Levitsky <mlevitsk@redhat.com> wrote:
> On Wed, 2020-07-22 at 19:19 +0300, Maxim Levitsky wrote:
> > On Wed, 2020-07-22 at 19:17 +0300, Maxim Levitsky wrote:
> > > Curently it is possible to hotplug a device and then immediatly
> > > hotunplug it before the OS notices, and that will result
> > > in missed unplug event since we can only send one attention button event.
> > >
> > > Moreover the device will stuck in unplugging state forever.
> > >
> > > Error out in such cases and rely on the caller (e.g libvirt) to retry
> > > the unplug a bit later
> > >
> > > Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
> > > ---
> > > hw/pci/pcie.c | 11 +++++++++++
> > > 1 file changed, 11 insertions(+)
> > >
> > > diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
> > > index 5b48bae0f6..9e836cf2f4 100644
> > > --- a/hw/pci/pcie.c
> > > +++ b/hw/pci/pcie.c
> > > @@ -402,6 +402,17 @@ static void pcie_cap_slot_plug_common(PCIDevice *hotplug_dev, DeviceState *dev,
> > > */
> > > error_setg_errno(errp, EBUSY, "slot is electromechanically locked");
> > > }
> > > +
> > > + if (sltsta & PCI_EXP_SLTSTA_ABP) {
> > > + /*
> > > + * Attention button is pressed, thus we can't send another
> > > + * hotpplug event
> > Typo here, forgot to refresh the commit.
> > > + */
> > > + error_setg_errno(errp, EBUSY,
> > > + "attention button is already pressed, can't "
> > > + "send another hotplug event");
> > > + }
> > > +
> > > }
> > >
> > > void pcie_cap_slot_pre_plug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
> ping.
CCing Julia since she was looking into PCI hotplug/unplug code recently.
>
> Best regards,
> Maxim Levitsky
>
>
next prev parent reply other threads:[~2020-07-30 11:40 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-22 16:17 [PATCH 0/1] RFC: pcie: parital fix for missing unplug events Maxim Levitsky
2020-07-22 16:17 ` [PATCH 1/1] pci/pcie: refuse another hotplug/unplug event if attention button is pending Maxim Levitsky
2020-07-22 16:19 ` Maxim Levitsky
2020-07-29 5:09 ` Maxim Levitsky
2020-07-30 11:38 ` Igor Mammedov [this message]
2020-07-30 16:04 ` Michael S. Tsirkin
2020-07-30 16:05 ` [PATCH 0/1] RFC: pcie: parital fix for missing unplug events Michael S. Tsirkin
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