[PATCH v4 00/10] pci: fix unhandled interrupt on shutdown

[PATCH v4 00/10] pci: fix unhandled interrupt on shutdown

[Michael S. Tsirkin]

Fam Zheng noticed that pci shutdown disables msi and msix of a device while
device is still active. This was intended to fix kexec with fusion devices but
had the unintended effect of breaking even regular shutdown when using virtio.

The same problem would affect any driver which doesn't register
a level interrupt handler when using msix.

I think the fix is to avoid touching device on shutdown:
we clear bus master anyway, so we won't get any more
msi interrupts, and bus reset will clear the msi/msix
state eventually anyway.

Patches 1-6 work well for me.
Given they affect all pci devices, and the bug has been there since 2.6 times,
I think there's no rush: we can merge them for 4.1.

At the same time, once merged, patches 1-4 will likely make a good stable
candidate.

Patches 7-10 compiled only, will need maintainer ack.

Please review, and consider at least 1-6 for 4.1.

Changes from v3:
	fix a copy-and-paste error in
	  pci: drop some duplicate code
	other patches are unchanged
	drop Cc stable for now
Changes from v2:
	move code from probe to device enumeration
	add patches to unexport pci_msi_off

Michael S. Tsirkin (11):
  pci: export functions for msi/msix ctrl
  pci: move pci_msi_init_pci_dev to pci.c
  pci: drop some duplicate code
  pci: don't disable msi/msix at shutdown
  pci: make msi/msix shutdown functions static
  virtio_pci: drop msi_off on probe
  ntb: drop pci_msi_off call on probe
  mic: drop pci_msi_off call on probe
  pci: drop pci_msi_off calls from quirks
  pci: unexport pci_msi_off

 drivers/pci/pci.h                  | 25 +++++++++++++--
 include/linux/pci.h                |  5 ---
 drivers/misc/mic/host/mic_intr.c   |  2 --
 drivers/ntb/ntb_hw.c               |  2 --
 drivers/pci/msi.c                  | 62 ++++++++------------------------------
 drivers/pci/pci-driver.c           |  2 --
 drivers/pci/pci.c                  | 24 +++------------
 drivers/pci/probe.c                | 16 ++++++++++
 drivers/pci/quirks.c               |  2 --
 drivers/virtio/virtio_pci_common.c |  3 --
 10 files changed, 56 insertions(+), 88 deletions(-)

-- 
MST

[PATCH v4 01/10] pci: export functions for msi/msix ctrl

[Michael S. Tsirkin]

move pci_msi_set_enable and pci_msix_clear_and_set_ctrl out of msi.c, so
we can use them will be used which MSI isn't configured in kernel.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/pci/pci.h | 21 +++++++++++++++++++++
 drivers/pci/msi.c | 45 ++++++++++++---------------------------------
 2 files changed, 33 insertions(+), 33 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 4091f82..17f213d 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -146,6 +146,27 @@ static inline void pci_no_msi(void) { }
 static inline void pci_msi_init_pci_dev(struct pci_dev *dev) { }
 #endif
 
+static inline void pci_msi_set_enable(struct pci_dev *dev, int enable)
+{
+	u16 control;
+
+	pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);
+	control &= ~PCI_MSI_FLAGS_ENABLE;
+	if (enable)
+		control |= PCI_MSI_FLAGS_ENABLE;
+	pci_write_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, control);
+}
+
+static inline void pci_msix_clear_and_set_ctrl(struct pci_dev *dev, u16 clear, u16 set)
+{
+	u16 ctrl;
+
+	pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &ctrl);
+	ctrl &= ~clear;
+	ctrl |= set;
+	pci_write_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, ctrl);
+}
+
 void pci_realloc_get_opt(char *);
 
 static inline int pci_no_d1d2(struct pci_dev *dev)
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index c3e7dfc..9942f68 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -185,27 +185,6 @@ void __weak arch_restore_msi_irqs(struct pci_dev *dev)
 	return default_restore_msi_irqs(dev);
 }
 
-static void msi_set_enable(struct pci_dev *dev, int enable)
-{
-	u16 control;
-
-	pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);
-	control &= ~PCI_MSI_FLAGS_ENABLE;
-	if (enable)
-		control |= PCI_MSI_FLAGS_ENABLE;
-	pci_write_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, control);
-}
-
-static void msix_clear_and_set_ctrl(struct pci_dev *dev, u16 clear, u16 set)
-{
-	u16 ctrl;
-
-	pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &ctrl);
-	ctrl &= ~clear;
-	ctrl |= set;
-	pci_write_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, ctrl);
-}
-
 static inline __attribute_const__ u32 msi_mask(unsigned x)
 {
 	/* Don't shift by >= width of type */
@@ -452,7 +431,7 @@ static void __pci_restore_msi_state(struct pci_dev *dev)
 	entry = irq_get_msi_desc(dev->irq);
 
 	pci_intx_for_msi(dev, 0);
-	msi_set_enable(dev, 0);
+	pci_msi_set_enable(dev, 0);
 	arch_restore_msi_irqs(dev);
 
 	pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);
@@ -473,14 +452,14 @@ static void __pci_restore_msix_state(struct pci_dev *dev)
 
 	/* route the table */
 	pci_intx_for_msi(dev, 0);
-	msix_clear_and_set_ctrl(dev, 0,
+	pci_msix_clear_and_set_ctrl(dev, 0,
 				PCI_MSIX_FLAGS_ENABLE | PCI_MSIX_FLAGS_MASKALL);
 
 	arch_restore_msi_irqs(dev);
 	list_for_each_entry(entry, &dev->msi_list, list)
 		msix_mask_irq(entry, entry->masked);
 
-	msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0);
+	pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0);
 }
 
 void pci_restore_msi_state(struct pci_dev *dev)
@@ -647,7 +626,7 @@ static int msi_capability_init(struct pci_dev *dev, int nvec)
 	int ret;
 	unsigned mask;
 
-	msi_set_enable(dev, 0);	/* Disable MSI during set up */
+	pci_msi_set_enable(dev, 0);	/* Disable MSI during set up */
 
 	entry = msi_setup_entry(dev, nvec);
 	if (!entry)
@@ -683,7 +662,7 @@ static int msi_capability_init(struct pci_dev *dev, int nvec)
 
 	/* Set MSI enabled bits	 */
 	pci_intx_for_msi(dev, 0);
-	msi_set_enable(dev, 1);
+	pci_msi_set_enable(dev, 1);
 	dev->msi_enabled = 1;
 
 	dev->irq = entry->irq;
@@ -775,7 +754,7 @@ static int msix_capability_init(struct pci_dev *dev,
 	void __iomem *base;
 
 	/* Ensure MSI-X is disabled while it is set up */
-	msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
+	pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
 
 	pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &control);
 	/* Request & Map MSI-X table region */
@@ -801,7 +780,7 @@ static int msix_capability_init(struct pci_dev *dev,
 	 * MSI-X registers.  We need to mask all the vectors to prevent
 	 * interrupts coming in before they're fully set up.
 	 */
-	msix_clear_and_set_ctrl(dev, 0,
+	pci_msix_clear_and_set_ctrl(dev, 0,
 				PCI_MSIX_FLAGS_MASKALL | PCI_MSIX_FLAGS_ENABLE);
 
 	msix_program_entries(dev, entries);
@@ -814,7 +793,7 @@ static int msix_capability_init(struct pci_dev *dev,
 	pci_intx_for_msi(dev, 0);
 	dev->msix_enabled = 1;
 
-	msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0);
+	pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0);
 
 	return 0;
 
@@ -919,7 +898,7 @@ void pci_msi_shutdown(struct pci_dev *dev)
 	BUG_ON(list_empty(&dev->msi_list));
 	desc = list_first_entry(&dev->msi_list, struct msi_desc, list);
 
-	msi_set_enable(dev, 0);
+	pci_msi_set_enable(dev, 0);
 	pci_intx_for_msi(dev, 1);
 	dev->msi_enabled = 0;
 
@@ -1027,7 +1006,7 @@ void pci_msix_shutdown(struct pci_dev *dev)
 		__pci_msix_desc_mask_irq(entry, 1);
 	}
 
-	msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
+	pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
 	pci_intx_for_msi(dev, 1);
 	dev->msix_enabled = 0;
 }
@@ -1069,11 +1048,11 @@ void pci_msi_init_pci_dev(struct pci_dev *dev)
 	 */
 	dev->msi_cap = pci_find_capability(dev, PCI_CAP_ID_MSI);
 	if (dev->msi_cap)
-		msi_set_enable(dev, 0);
+		pci_msi_set_enable(dev, 0);
 
 	dev->msix_cap = pci_find_capability(dev, PCI_CAP_ID_MSIX);
 	if (dev->msix_cap)
-		msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
+		pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
 }
 
 /**
-- 
MST

[PATCH v4 02/10] pci: move pci_msi_init_pci_dev to pci.c

[Michael S. Tsirkin]

commit d5dea7d95c48d7bc951cee4910a7fd9c0cd26fb0
    "PCI: msi: Disable msi interrupts when we initialize a pci device"
fixes kexec when the booting kernel does not enable msi interupts.

Unfortunately the relevant functionality is in msi.c so it isn't
compiled in when CONFIG_PCI_MSI is off, which means such configurations
would still get interrupt storms.

Fix by moving the function to pci.c, and compiling it unconditionally.

Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/pci/pci.h   |  2 --
 drivers/pci/msi.c   | 17 -----------------
 drivers/pci/probe.c | 19 +++++++++++++++++++
 3 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 17f213d..a964569 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -140,10 +140,8 @@ extern unsigned int pci_pm_d3_delay;
 
 #ifdef CONFIG_PCI_MSI
 void pci_no_msi(void);
-void pci_msi_init_pci_dev(struct pci_dev *dev);
 #else
 static inline void pci_no_msi(void) { }
-static inline void pci_msi_init_pci_dev(struct pci_dev *dev) { }
 #endif
 
 static inline void pci_msi_set_enable(struct pci_dev *dev, int enable)
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 9942f68..ae3f7cc 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -1038,23 +1038,6 @@ int pci_msi_enabled(void)
 }
 EXPORT_SYMBOL(pci_msi_enabled);
 
-void pci_msi_init_pci_dev(struct pci_dev *dev)
-{
-	INIT_LIST_HEAD(&dev->msi_list);
-
-	/* Disable the msi hardware to avoid screaming interrupts
-	 * during boot.  This is the power on reset default so
-	 * usually this should be a noop.
-	 */
-	dev->msi_cap = pci_find_capability(dev, PCI_CAP_ID_MSI);
-	if (dev->msi_cap)
-		pci_msi_set_enable(dev, 0);
-
-	dev->msix_cap = pci_find_capability(dev, PCI_CAP_ID_MSIX);
-	if (dev->msix_cap)
-		pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
-}
-
 /**
  * pci_enable_msi_range - configure device's MSI capability structure
  * @dev: device to configure
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 8d2f400..45d6d5c 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1483,6 +1483,25 @@ static struct pci_dev *pci_scan_device(struct pci_bus *bus, int devfn)
 	return dev;
 }
 
+static void pci_msi_init_pci_dev(struct pci_dev *dev)
+{
+#ifdef CONFIG_PCI_MSI
+	INIT_LIST_HEAD(&dev->msi_list);
+#endif
+
+	/* Disable the msi hardware to avoid screaming interrupts
+	 * during boot.  This is the power on reset default so
+	 * usually this should be a noop.
+	 */
+	dev->msi_cap = pci_find_capability(dev, PCI_CAP_ID_MSI);
+	if (dev->msi_cap)
+		pci_msi_set_enable(dev, 0);
+
+	dev->msix_cap = pci_find_capability(dev, PCI_CAP_ID_MSIX);
+	if (dev->msix_cap)
+		pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
+}
+
 static void pci_init_capabilities(struct pci_dev *dev)
 {
 	/* MSI/MSI-X list */
-- 
MST

[PATCH v4 03/10] pci: drop some duplicate code

[Michael S. Tsirkin]

pci_msi_init_pci_dev and pci_msi_off share a lot of code.
This used to be justified since pci_msi_init_pci_dev
wasn't compiled in when CONFIG_PCI_MSI is off.
Now that it is, let's reuse code.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/pci/pci.c   | 23 ++++-------------------
 drivers/pci/probe.c | 11 ++++-------
 2 files changed, 8 insertions(+), 26 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 81f06e8..fcee8ea 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3106,26 +3106,11 @@ EXPORT_SYMBOL_GPL(pci_check_and_unmask_intx);
  */
 void pci_msi_off(struct pci_dev *dev)
 {
-	int pos;
-	u16 control;
+	if (dev->msi_cap)
+		pci_msi_set_enable(dev, 0);
 
-	/*
-	 * This looks like it could go in msi.c, but we need it even when
-	 * CONFIG_PCI_MSI=n.  For the same reason, we can't use
-	 * dev->msi_cap or dev->msix_cap here.
-	 */
-	pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
-	if (pos) {
-		pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &control);
-		control &= ~PCI_MSI_FLAGS_ENABLE;
-		pci_write_config_word(dev, pos + PCI_MSI_FLAGS, control);
-	}
-	pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
-	if (pos) {
-		pci_read_config_word(dev, pos + PCI_MSIX_FLAGS, &control);
-		control &= ~PCI_MSIX_FLAGS_ENABLE;
-		pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
-	}
+	if (dev->msix_cap)
+		pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
 }
 EXPORT_SYMBOL_GPL(pci_msi_off);
 
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 45d6d5c..baf8ddd 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1489,17 +1489,14 @@ static void pci_msi_init_pci_dev(struct pci_dev *dev)
 	INIT_LIST_HEAD(&dev->msi_list);
 #endif
 
+	dev->msi_cap = pci_find_capability(dev, PCI_CAP_ID_MSI);
+	dev->msix_cap = pci_find_capability(dev, PCI_CAP_ID_MSIX);
+
 	/* Disable the msi hardware to avoid screaming interrupts
 	 * during boot.  This is the power on reset default so
 	 * usually this should be a noop.
 	 */
-	dev->msi_cap = pci_find_capability(dev, PCI_CAP_ID_MSI);
-	if (dev->msi_cap)
-		pci_msi_set_enable(dev, 0);
-
-	dev->msix_cap = pci_find_capability(dev, PCI_CAP_ID_MSIX);
-	if (dev->msix_cap)
-		pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
+	pci_msi_off(dev);
 }
 
 static void pci_init_capabilities(struct pci_dev *dev)
-- 
MST

[PATCH v4 04/10] pci: don't disable msi/msix at shutdown

[Michael S. Tsirkin]

This partially reverts commit d52877c7b1afb8c37ebe17e2005040b79cb618b0:
	"pci/irq: let pci_device_shutdown to call pci_msi_shutdown v2"

It's un-necessary now that we disable msi at start, and it actually
turns out to cause problems: some device drivers don't register a level
interrupt handler when they detect msi/msix capability, switching off
msi while device is going causes device to assert a level interrupt
which is never de-asserted, causing a kernel hang.

In particular, this was observed with virtio.

Cc: Yinghai Lu <yhlu.kernel.send@gmail.com>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Reported-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/pci/pci-driver.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 3cb2210..38a602c 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -450,8 +450,6 @@ static void pci_device_shutdown(struct device *dev)
 
 	if (drv && drv->shutdown)
 		drv->shutdown(pci_dev);
-	pci_msi_shutdown(pci_dev);
-	pci_msix_shutdown(pci_dev);
 
 #ifdef CONFIG_KEXEC
 	/*
-- 
MST

[PATCH v4 05/10] pci: make msi/msix shutdown functions static

[Michael S. Tsirkin]

pci_msi_shutdown and pci_msix_shutdown are now internal to msi.c, drop
them from header and make them static.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/linux/pci.h | 4 ----
 drivers/pci/msi.c   | 4 ++--
 2 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 211e9da..a34df45 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1209,11 +1209,9 @@ struct msix_entry {
 
 #ifdef CONFIG_PCI_MSI
 int pci_msi_vec_count(struct pci_dev *dev);
-void pci_msi_shutdown(struct pci_dev *dev);
 void pci_disable_msi(struct pci_dev *dev);
 int pci_msix_vec_count(struct pci_dev *dev);
 int pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries, int nvec);
-void pci_msix_shutdown(struct pci_dev *dev);
 void pci_disable_msix(struct pci_dev *dev);
 void pci_restore_msi_state(struct pci_dev *dev);
 int pci_msi_enabled(void);
@@ -1237,13 +1235,11 @@ static inline int pci_enable_msix_exact(struct pci_dev *dev,
 }
 #else
 static inline int pci_msi_vec_count(struct pci_dev *dev) { return -ENOSYS; }
-static inline void pci_msi_shutdown(struct pci_dev *dev) { }
 static inline void pci_disable_msi(struct pci_dev *dev) { }
 static inline int pci_msix_vec_count(struct pci_dev *dev) { return -ENOSYS; }
 static inline int pci_enable_msix(struct pci_dev *dev,
 				  struct msix_entry *entries, int nvec)
 { return -ENOSYS; }
-static inline void pci_msix_shutdown(struct pci_dev *dev) { }
 static inline void pci_disable_msix(struct pci_dev *dev) { }
 static inline void pci_restore_msi_state(struct pci_dev *dev) { }
 static inline int pci_msi_enabled(void) { return 0; }
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index ae3f7cc..a353222 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -887,7 +887,7 @@ int pci_msi_vec_count(struct pci_dev *dev)
 }
 EXPORT_SYMBOL(pci_msi_vec_count);
 
-void pci_msi_shutdown(struct pci_dev *dev)
+static void pci_msi_shutdown(struct pci_dev *dev)
 {
 	struct msi_desc *desc;
 	u32 mask;
@@ -993,7 +993,7 @@ int pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries, int nvec)
 }
 EXPORT_SYMBOL(pci_enable_msix);
 
-void pci_msix_shutdown(struct pci_dev *dev)
+static void pci_msix_shutdown(struct pci_dev *dev)
 {
 	struct msi_desc *entry;
 
-- 
MST

[PATCH v4 06/10] virtio_pci: drop msi_off on probe

[Michael S. Tsirkin]

pci core now disables msi on probe automatically,
drop this from device-specific code.

Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/virtio/virtio_pci_common.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
index e894eb2..806bb2c 100644
--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c
@@ -501,9 +501,6 @@ static int virtio_pci_probe(struct pci_dev *pci_dev,
 	INIT_LIST_HEAD(&vp_dev->virtqueues);
 	spin_lock_init(&vp_dev->lock);
 
-	/* Disable MSI/MSIX to bring device to a known good state. */
-	pci_msi_off(pci_dev);
-
 	/* enable the device */
 	rc = pci_enable_device(pci_dev);
 	if (rc)
-- 
MST

[PATCH v4 06/10] virtio_pci: drop msi_off on probe

[Michael S. Tsirkin]

pci core now disables msi on probe automatically,
drop this from device-specific code.

Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/virtio/virtio_pci_common.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
index e894eb2..806bb2c 100644
--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c
@@ -501,9 +501,6 @@ static int virtio_pci_probe(struct pci_dev *pci_dev,
 	INIT_LIST_HEAD(&vp_dev->virtqueues);
 	spin_lock_init(&vp_dev->lock);
 
-	/* Disable MSI/MSIX to bring device to a known good state. */
-	pci_msi_off(pci_dev);
-
 	/* enable the device */
 	rc = pci_enable_device(pci_dev);
 	if (rc)
-- 
MST

[PATCH v4 07/10] ntb: drop pci_msi_off call on probe

[Michael S. Tsirkin]

pci core now disables msi on probe automatically,
drop this from device-specific code.

Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/ntb/ntb_hw.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
index cd29b10..8225cbc 100644
--- a/drivers/ntb/ntb_hw.c
+++ b/drivers/ntb/ntb_hw.c
@@ -1313,8 +1313,6 @@ static int ntb_setup_intx(struct ntb_device *ndev)
 	struct pci_dev *pdev = ndev->pdev;
 	int rc;
 
-	pci_msi_off(pdev);
-
 	/* Verify intx is enabled */
 	pci_intx(pdev, 1);
 
-- 
MST

[PATCH v4 08/10] mic: drop pci_msi_off call on probe

[Michael S. Tsirkin]

pci core now disables msi on probe automatically,
drop this from device-specific code.

Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/misc/mic/host/mic_intr.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/misc/mic/host/mic_intr.c b/drivers/misc/mic/host/mic_intr.c
index d686f28..b4ca6c8 100644
--- a/drivers/misc/mic/host/mic_intr.c
+++ b/drivers/misc/mic/host/mic_intr.c
@@ -363,8 +363,6 @@ static int mic_setup_intx(struct mic_device *mdev, struct pci_dev *pdev)
 {
 	int rc;
 
-	pci_msi_off(pdev);
-
 	/* Enable intx */
 	pci_intx(pdev, 1);
 	rc = mic_setup_callbacks(mdev);
-- 
MST

[PATCH v4 09/10] pci: drop pci_msi_off calls from quirks

[Michael S. Tsirkin]

pci core now disables msi on probe automatically,
drop this from device-specific quirks.

Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/pci/quirks.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 85f247e..df3e718 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -1600,7 +1600,6 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL,	PCI_DEVICE_ID_INTEL_EESSC,	quirk_a
 
 static void quirk_pcie_mch(struct pci_dev *pdev)
 {
-	pci_msi_off(pdev);
 	pdev->no_msi = 1;
 }
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL,	PCI_DEVICE_ID_INTEL_E7520_MCH,	quirk_pcie_mch);
@@ -1614,7 +1613,6 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL,	PCI_DEVICE_ID_INTEL_E7525_MCH,	quir
  */
 static void quirk_pcie_pxh(struct pci_dev *dev)
 {
-	pci_msi_off(dev);
 	dev->no_msi = 1;
 	dev_warn(&dev->dev, "PXH quirk detected; SHPC device MSI disabled\n");
 }
-- 
MST

[PATCH v4 10/10] pci: unexport pci_msi_off

[Michael S. Tsirkin]

Now one should be using pci_msi_off now, unexport it and move the
declaration to internal header to prevent misuse.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/pci/pci.h   | 2 ++
 include/linux/pci.h | 1 -
 drivers/pci/pci.c   | 2 +-
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index a964569..dd17615 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -144,6 +144,8 @@ void pci_no_msi(void);
 static inline void pci_no_msi(void) { }
 #endif
 
+void pci_msi_off(struct pci_dev *dev);
+
 static inline void pci_msi_set_enable(struct pci_dev *dev, int enable)
 {
 	u16 control;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index a34df45..ef15f91 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -970,7 +970,6 @@ void pci_intx(struct pci_dev *dev, int enable);
 bool pci_intx_mask_supported(struct pci_dev *dev);
 bool pci_check_and_mask_intx(struct pci_dev *dev);
 bool pci_check_and_unmask_intx(struct pci_dev *dev);
-void pci_msi_off(struct pci_dev *dev);
 int pci_set_dma_max_seg_size(struct pci_dev *dev, unsigned int size);
 int pci_set_dma_seg_boundary(struct pci_dev *dev, unsigned long mask);
 int pci_wait_for_pending(struct pci_dev *dev, int pos, u16 mask);
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index fcee8ea..54cefb4 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3103,6 +3103,7 @@ EXPORT_SYMBOL_GPL(pci_check_and_unmask_intx);
  * If you want to use MSI, see pci_enable_msi() and friends.
  * This is a lower-level primitive that allows us to disable
  * MSI operation at the device level.
+ * Not for use by drivers.
  */
 void pci_msi_off(struct pci_dev *dev)
 {
@@ -3112,7 +3113,6 @@ void pci_msi_off(struct pci_dev *dev)
 	if (dev->msix_cap)
 		pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
 }
-EXPORT_SYMBOL_GPL(pci_msi_off);
 
 int pci_set_dma_max_seg_size(struct pci_dev *dev, unsigned int size)
 {
-- 
MST

Re: [PATCH v4 03/10] pci: drop some duplicate code

[Yijing Wang]

On 2015/3/26 19:37, Michael S. Tsirkin wrote:
> pci_msi_init_pci_dev and pci_msi_off share a lot of code.
> This used to be justified since pci_msi_init_pci_dev
> wasn't compiled in when CONFIG_PCI_MSI is off.
> Now that it is, let's reuse code.

It's not correct, pci_msi_off() would be used in quirk when the msi_cap is not initialized.

For example:

/*
 * It's possible for the MSI to get corrupted if shpc and acpi
 * are used together on certain PXH-based systems.
 */
static void quirk_pcie_pxh(struct pci_dev *dev)
{
	pci_msi_off(dev);
	dev->no_msi = 1;
	dev_warn(&dev->dev, "PXH quirk detected; SHPC device MSI disabled\n");
}
DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL,	PCI_DEVICE_ID_INTEL_PXHD_0,	quirk_pcie_pxh);


> 
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>  drivers/pci/pci.c   | 23 ++++-------------------
>  drivers/pci/probe.c | 11 ++++-------
>  2 files changed, 8 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 81f06e8..fcee8ea 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -3106,26 +3106,11 @@ EXPORT_SYMBOL_GPL(pci_check_and_unmask_intx);
>   */
>  void pci_msi_off(struct pci_dev *dev)
>  {
> -	int pos;
> -	u16 control;
> +	if (dev->msi_cap)
> +		pci_msi_set_enable(dev, 0);
>  
> -	/*
> -	 * This looks like it could go in msi.c, but we need it even when
> -	 * CONFIG_PCI_MSI=n.  For the same reason, we can't use
> -	 * dev->msi_cap or dev->msix_cap here.
> -	 */
> -	pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
> -	if (pos) {
> -		pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &control);
> -		control &= ~PCI_MSI_FLAGS_ENABLE;
> -		pci_write_config_word(dev, pos + PCI_MSI_FLAGS, control);
> -	}
> -	pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
> -	if (pos) {
> -		pci_read_config_word(dev, pos + PCI_MSIX_FLAGS, &control);
> -		control &= ~PCI_MSIX_FLAGS_ENABLE;
> -		pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
> -	}
> +	if (dev->msix_cap)
> +		pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
>  }
>  EXPORT_SYMBOL_GPL(pci_msi_off);
>  
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 45d6d5c..baf8ddd 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -1489,17 +1489,14 @@ static void pci_msi_init_pci_dev(struct pci_dev *dev)
>  	INIT_LIST_HEAD(&dev->msi_list);
>  #endif
>  
> +	dev->msi_cap = pci_find_capability(dev, PCI_CAP_ID_MSI);
> +	dev->msix_cap = pci_find_capability(dev, PCI_CAP_ID_MSIX);
> +
>  	/* Disable the msi hardware to avoid screaming interrupts
>  	 * during boot.  This is the power on reset default so
>  	 * usually this should be a noop.
>  	 */
> -	dev->msi_cap = pci_find_capability(dev, PCI_CAP_ID_MSI);
> -	if (dev->msi_cap)
> -		pci_msi_set_enable(dev, 0);
> -
> -	dev->msix_cap = pci_find_capability(dev, PCI_CAP_ID_MSIX);
> -	if (dev->msix_cap)
> -		pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
> +	pci_msi_off(dev);
>  }
>  
>  static void pci_init_capabilities(struct pci_dev *dev)
> 


-- 
Thanks!
Yijing