diff mbox series

[5/6] pcie: fast unplug when slot power is off

Message ID 20211011120504.254053-6-kraxel@redhat.com (mailing list archive)
State New, archived
Headers show
Series RfC: try improve native hotplug for pcie root ports | expand

Commit Message

Gerd Hoffmann Oct. 11, 2021, 12:05 p.m. UTC
In case the slot is powered off (and the power indicator turned off too)
we can unplug right away, without round-trip to the guest.

Also clear pending attention button press, there is nothing to care
about any more.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/pci/pcie.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

Comments

Michael S. Tsirkin Oct. 12, 2021, 5:56 a.m. UTC | #1
On Mon, Oct 11, 2021 at 02:05:03PM +0200, Gerd Hoffmann wrote:
> In case the slot is powered off (and the power indicator turned off too)
> we can unplug right away, without round-trip to the guest.
> 
> Also clear pending attention button press, there is nothing to care
> about any more.
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  hw/pci/pcie.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
> index 70fc11ba4c7d..f3ac04399969 100644
> --- a/hw/pci/pcie.c
> +++ b/hw/pci/pcie.c
> @@ -561,6 +561,16 @@ void pcie_cap_slot_unplug_request_cb(HotplugHandler *hotplug_dev,
>          return;
>      }
>  
> +    if (((sltctl & PCI_EXP_SLTCTL_PIC) == PCI_EXP_SLTCTL_PWR_IND_OFF) &&
> +        ((sltctl & PCI_EXP_SLTCTL_PCC) == PCI_EXP_SLTCTL_PWR_OFF)) {
> +        /* slot is powered off -> unplug without round-trip to the guest */
> +        pcie_cap_slot_do_unplug(hotplug_pdev);
> +        hotplug_event_notify(hotplug_pdev);
> +        pci_word_test_and_clear_mask(exp_cap + PCI_EXP_SLTSTA,
> +                                     PCI_EXP_SLTSTA_ABP);

Does this handle all the things including link status etc btw?
I don't remember off-hand.

> +        return;
> +    }
> +
>      pcie_cap_slot_push_attention_button(hotplug_pdev);
>  }
>  
> -- 
> 2.31.1
Gerd Hoffmann Oct. 12, 2021, 6:46 a.m. UTC | #2
On Tue, Oct 12, 2021 at 01:56:31AM -0400, Michael S. Tsirkin wrote:
> On Mon, Oct 11, 2021 at 02:05:03PM +0200, Gerd Hoffmann wrote:
> > In case the slot is powered off (and the power indicator turned off too)
> > we can unplug right away, without round-trip to the guest.
> > 
> > Also clear pending attention button press, there is nothing to care
> > about any more.
> > 
> > Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> > ---
> >  hw/pci/pcie.c | 10 ++++++++++
> >  1 file changed, 10 insertions(+)
> > 
> > diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
> > index 70fc11ba4c7d..f3ac04399969 100644
> > --- a/hw/pci/pcie.c
> > +++ b/hw/pci/pcie.c
> > @@ -561,6 +561,16 @@ void pcie_cap_slot_unplug_request_cb(HotplugHandler *hotplug_dev,
> >          return;
> >      }
> >  
> > +    if (((sltctl & PCI_EXP_SLTCTL_PIC) == PCI_EXP_SLTCTL_PWR_IND_OFF) &&
> > +        ((sltctl & PCI_EXP_SLTCTL_PCC) == PCI_EXP_SLTCTL_PWR_OFF)) {
> > +        /* slot is powered off -> unplug without round-trip to the guest */
> > +        pcie_cap_slot_do_unplug(hotplug_pdev);
> > +        hotplug_event_notify(hotplug_pdev);
> > +        pci_word_test_and_clear_mask(exp_cap + PCI_EXP_SLTSTA,
> > +                                     PCI_EXP_SLTSTA_ABP);
> 
> Does this handle all the things including link status etc btw?
> I don't remember off-hand.

Yes.  See patch #4 which moves the relevant code to the new
pcie_cap_slot_do_unplug() helper.

take care,
  Gerd
diff mbox series

Patch

diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
index 70fc11ba4c7d..f3ac04399969 100644
--- a/hw/pci/pcie.c
+++ b/hw/pci/pcie.c
@@ -561,6 +561,16 @@  void pcie_cap_slot_unplug_request_cb(HotplugHandler *hotplug_dev,
         return;
     }
 
+    if (((sltctl & PCI_EXP_SLTCTL_PIC) == PCI_EXP_SLTCTL_PWR_IND_OFF) &&
+        ((sltctl & PCI_EXP_SLTCTL_PCC) == PCI_EXP_SLTCTL_PWR_OFF)) {
+        /* slot is powered off -> unplug without round-trip to the guest */
+        pcie_cap_slot_do_unplug(hotplug_pdev);
+        hotplug_event_notify(hotplug_pdev);
+        pci_word_test_and_clear_mask(exp_cap + PCI_EXP_SLTSTA,
+                                     PCI_EXP_SLTSTA_ABP);
+        return;
+    }
+
     pcie_cap_slot_push_attention_button(hotplug_pdev);
 }