linux-kernel - [PATCH 2/3 v2] Refactor msi/msix restore code Part2

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Message-ID: <51FF527F.7080904@oracle.com>
Date:	Mon, 05 Aug 2013 15:21:35 +0800
From:	Zhenzhong Duan <zhenzhong.duan@...cle.com>
To:	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	xen-devel <xen-devel@...ts.xen.org>
CC:	Bjorn Helgaas <bhelgaas@...gle.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	Feng Jin <joe.jin@...cle.com>,
	Sucheta Chakraborty <sucheta.chakraborty@...gic.com>
Subject: [PATCH 2/3 v2] Refactor msi/msix restore code Part2

xen_initdom_restore_msi_irqs trigger a hypercall to restore addr/data/mask
in dom0. It's better to do the same in default_restore_msi_irqs for baremetal.

Move restore of mask in default_restore_msi_irqs, this could avoid mask
restored twice in dom0, and the logic for baremetal keep same.

First mask restore is in xen_initdom_restore_msi_irqs->PHYSDEVOP_restore_msi,
Second restore is __pci_restore_msix_state->msix_mask_irq.

Mask bits are under full control of xen, and the entry->masked in dom0 kernel
is invalid. restore an invalid value to mask register could mask the msix
interrupt.

Without fix, qlcnic driver calling pci_reset_function will lost interrupt
in dom0.

Tested-by: Sucheta Chakraborty <sucheta.chakraborty@...gic.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@...cle.com>
---
 drivers/pci/msi.c |   17 ++++++++++++++---
 1 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 87223ae..922fb49 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -216,6 +216,8 @@ void unmask_msi_irq(struct irq_data *data)
 #ifdef HAVE_DEFAULT_MSI_RESTORE_IRQS
 void default_restore_msi_irqs(struct pci_dev *dev, int irq)
 {
+	int pos;
+	u16 control;
 	struct msi_desc *entry;
 
 	entry = NULL;
@@ -228,8 +230,19 @@ void default_restore_msi_irqs(struct pci_dev *dev, int irq)
 		entry = irq_get_msi_desc(irq);
 	}
 
-	if (entry)
+	if (entry) {
 		write_msi_msg(irq, &entry->msg);
+		if (dev->msix_enabled) {
+			msix_mask_irq(entry, entry->masked);
+			readl(entry->mask_base);
+		} else {
+			pos = entry->msi_attrib.pos;
+			pci_read_config_word(dev, pos + PCI_MSI_FLAGS,
+					     &control);
+			msi_mask_irq(entry, msi_capable_mask(control),
+				     entry->masked);
+		}
+	}
 }
 #endif
 
@@ -406,7 +419,6 @@ static void __pci_restore_msi_state(struct pci_dev *dev)
 	arch_restore_msi_irqs(dev, dev->irq);
 
 	pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);
-	msi_mask_irq(entry, msi_capable_mask(control), entry->masked);
 	control &= ~PCI_MSI_FLAGS_QSIZE;
 	control |= (entry->msi_attrib.multiple << 4) | PCI_MSI_FLAGS_ENABLE;
 	pci_write_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, control);
@@ -430,7 +442,6 @@ static void __pci_restore_msix_state(struct pci_dev *dev)
 
 	list_for_each_entry(entry, &dev->msi_list, list) {
 		arch_restore_msi_irqs(dev, entry->irq);
-		msix_mask_irq(entry, entry->masked);
 	}
 
 	control &= ~PCI_MSIX_FLAGS_MASKALL;
-- 
1.7.3

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