PCI: pciehp: Do not handle events if interrupts are masked

mainline inclusion
from mainline-4.19-rc4
commit 720d6a671a6e2cf2b9ed032279b7c21c122bed7e
category: bugfix
bugzilla: 12802
CVE: NA

-------------------------------------------------

PCIe native hotplug shares MSI vector with native PME so the interrupt
handler might get called even the hotplug interrupt is masked. In that case
we should not handle any events because the interrupt was not meant for us.

Modify the PCIe hotplug interrupt handler to check this accordingly and
bail out if it finds out that the interrupt was not about hotplug.
Signed-off-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NLukas Wunner <lukas@wunner.de>
Signed-off-by: NXiongfeng Wang <wangxiongfeng2@huawei.com>
Reviewed-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/pci/hotplug/pciehp_hpc.c

@@ -547,9 +547,11 @@ static irqreturn_t pciehp_isr(int irq, void *dev_id)
 	u16 status, events;
 
 	/*
-	 * Interrupts only occur in D3hot or shallower (PCIe r4.0, sec 6.7.3.4).
+	 * Interrupts only occur in D3hot or shallower and only if enabled
+	 * in the Slot Control register (PCIe r4.0, sec 6.7.3.4).
 	 */
-	if (pdev->current_state == PCI_D3cold)
+	if (pdev->current_state == PCI_D3cold ||
+	    (!(ctrl->slot_ctrl & PCI_EXP_SLTCTL_HPIE) && !pciehp_poll_mode))
 		return IRQ_NONE;
 
 	/*