/*
 * PCI Backend - Provides a Virtual PCI bus (with real devices)
 *               to the frontend
 *
 *   Author: Ryan Wilson <hap9@epoch.ncsc.mil>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/list.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/mutex.h>
#include "pciback.h"

#define PCI_SLOT_MAX 32

struct vpci_dev_data {
	/* Access to dev_list must be protected by lock */
	struct list_head dev_list[PCI_SLOT_MAX];
	struct mutex lock;
};

static inline struct list_head *list_first(struct list_head *head)
{
	return head->next;
}

static struct pci_dev *__xen_pcibk_get_pci_dev(struct xen_pcibk_device *pdev,
					       unsigned int domain,
					       unsigned int bus,
					       unsigned int devfn)
{
	struct pci_dev_entry *entry;
	struct pci_dev *dev = NULL;
	struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;

	if (domain != 0 || bus != 0)
		return NULL;

	if (PCI_SLOT(devfn) < PCI_SLOT_MAX) {
		mutex_lock(&vpci_dev->lock);

		list_for_each_entry(entry,
				    &vpci_dev->dev_list[PCI_SLOT(devfn)],
				    list) {
			if (PCI_FUNC(entry->dev->devfn) == PCI_FUNC(devfn)) {
				dev = entry->dev;
				break;
			}
		}

		mutex_unlock(&vpci_dev->lock);
	}
	return dev;
}

static inline int match_slot(struct pci_dev *l, struct pci_dev *r)
{
	if (pci_domain_nr(l->bus) == pci_domain_nr(r->bus)
	    && l->bus == r->bus && PCI_SLOT(l->devfn) == PCI_SLOT(r->devfn))
		return 1;

	return 0;
}

static int __xen_pcibk_add_pci_dev(struct xen_pcibk_device *pdev,
				   struct pci_dev *dev, int devid,
				   publish_pci_dev_cb publish_cb)
{
	int err = 0, slot, func = -1;
	struct pci_dev_entry *t, *dev_entry;
	struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;

	if ((dev->class >> 24) == PCI_BASE_CLASS_BRIDGE) {
		err = -EFAULT;
		xenbus_dev_fatal(pdev->xdev, err,
				 "Can't export bridges on the virtual PCI bus");
		goto out;
	}

	dev_entry = kmalloc(sizeof(*dev_entry), GFP_KERNEL);
	if (!dev_entry) {
		err = -ENOMEM;
		xenbus_dev_fatal(pdev->xdev, err,
				 "Error adding entry to virtual PCI bus");
		goto out;
	}

	dev_entry->dev = dev;

	mutex_lock(&vpci_dev->lock);

	/*
	 * Keep multi-function devices together on the virtual PCI bus, except
	 * virtual functions.
	 */
	if (!dev->is_virtfn) {
		for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
			if (list_empty(&vpci_dev->dev_list[slot]))
				continue;

			t = list_entry(list_first(&vpci_dev->dev_list[slot]),
				       struct pci_dev_entry, list);

			if (match_slot(dev, t->dev)) {
				pr_info("vpci: %s: assign to virtual slot %d func %d\n",
					pci_name(dev), slot,
					PCI_FUNC(dev->devfn));
				list_add_tail(&dev_entry->list,
					      &vpci_dev->dev_list[slot]);
				func = PCI_FUNC(dev->devfn);
				goto unlock;
			}
		}
	}

	/* Assign to a new slot on the virtual PCI bus */
	for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
		if (list_empty(&vpci_dev->dev_list[slot])) {
			pr_info("vpci: %s: assign to virtual slot %d\n",
				pci_name(dev), slot);
			list_add_tail(&dev_entry->list,
				      &vpci_dev->dev_list[slot]);
			func = dev->is_virtfn ? 0 : PCI_FUNC(dev->devfn);
			goto unlock;
		}
	}

	err = -ENOMEM;
	xenbus_dev_fatal(pdev->xdev, err,
			 "No more space on root virtual PCI bus");

unlock:
	mutex_unlock(&vpci_dev->lock);

	/* Publish this device. */
	if (!err)
		err = publish_cb(pdev, 0, 0, PCI_DEVFN(slot, func), devid);
	else
		kfree(dev_entry);

out:
	return err;
}

static void __xen_pcibk_release_pci_dev(struct xen_pcibk_device *pdev,
					struct pci_dev *dev, bool lock)
{
	int slot;
	struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
	struct pci_dev *found_dev = NULL;

	mutex_lock(&vpci_dev->lock);

	for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
		struct pci_dev_entry *e;

		list_for_each_entry(e, &vpci_dev->dev_list[slot], list) {
			if (e->dev == dev) {
				list_del(&e->list);
				found_dev = e->dev;
				kfree(e);
				goto out;
			}
		}
	}

out:
	mutex_unlock(&vpci_dev->lock);

	if (found_dev) {
		if (lock)
			device_lock(&found_dev->dev);
		pcistub_put_pci_dev(found_dev);
		if (lock)
			device_unlock(&found_dev->dev);
	}
}

static int __xen_pcibk_init_devices(struct xen_pcibk_device *pdev)
{
	int slot;
	struct vpci_dev_data *vpci_dev;

	vpci_dev = kmalloc(sizeof(*vpci_dev), GFP_KERNEL);
	if (!vpci_dev)
		return -ENOMEM;

	mutex_init(&vpci_dev->lock);

	for (slot = 0; slot < PCI_SLOT_MAX; slot++)
		INIT_LIST_HEAD(&vpci_dev->dev_list[slot]);

	pdev->pci_dev_data = vpci_dev;

	return 0;
}

static int __xen_pcibk_publish_pci_roots(struct xen_pcibk_device *pdev,
					 publish_pci_root_cb publish_cb)
{
	/* The Virtual PCI bus has only one root */
	return publish_cb(pdev, 0, 0);
}

static void __xen_pcibk_release_devices(struct xen_pcibk_device *pdev)
{
	int slot;
	struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;

	for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
		struct pci_dev_entry *e, *tmp;
		list_for_each_entry_safe(e, tmp, &vpci_dev->dev_list[slot],
					 list) {
			struct pci_dev *dev = e->dev;
			list_del(&e->list);
			device_lock(&dev->dev);
			pcistub_put_pci_dev(dev);
			device_unlock(&dev->dev);
			kfree(e);
		}
	}

	kfree(vpci_dev);
	pdev->pci_dev_data = NULL;
}

static int __xen_pcibk_get_pcifront_dev(struct pci_dev *pcidev,
					struct xen_pcibk_device *pdev,
					unsigned int *domain, unsigned int *bus,
					unsigned int *devfn)
{
	struct pci_dev_entry *entry;
	struct pci_dev *dev = NULL;
	struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
	int found = 0, slot;

	mutex_lock(&vpci_dev->lock);
	for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
		list_for_each_entry(entry,
			    &vpci_dev->dev_list[slot],
			    list) {
			dev = entry->dev;
			if (dev && dev->bus->number == pcidev->bus->number
				&& pci_domain_nr(dev->bus) ==
					pci_domain_nr(pcidev->bus)
				&& dev->devfn == pcidev->devfn) {
				found = 1;
				*domain = 0;
				*bus = 0;
				*devfn = PCI_DEVFN(slot,
					 PCI_FUNC(pcidev->devfn));
			}
		}
	}
	mutex_unlock(&vpci_dev->lock);
	return found;
}

const struct xen_pcibk_backend xen_pcibk_vpci_backend = {
	.name		= "vpci",
	.init		= __xen_pcibk_init_devices,
	.free		= __xen_pcibk_release_devices,
	.find		= __xen_pcibk_get_pcifront_dev,
	.publish	= __xen_pcibk_publish_pci_roots,
	.release	= __xen_pcibk_release_pci_dev,
	.add		= __xen_pcibk_add_pci_dev,
	.get		= __xen_pcibk_get_pci_dev,
};
that but it can also hurt
us:

Imagine a single hyperthreaded CPU (Intel(R) Atom(TM) CPU N270, for
example) which updates the microcode on the BSP but since the microcode
engine is shared between the two threads, the update on CPU1 doesn't
happen because it has already happened on CPU0 and we don't find a newer
microcode revision on CPU1.

Which doesn't set the intel_ucode_patch pointer and at initrd
jettisoning time we don't save the microcode patch for later
application.

Now, when we suspend to RAM, the loaded microcode gets cleared so we
need to reload but there's no patch saved in the cache.

Removing the optimization fixes this issue and all is fine and dandy.

Fixes: 06b8534cb728 ("x86/microcode: Rework microcode loading")
Signed-off-by: Borislav Petkov &lt;bp@suse.de&gt;
Reviewed-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Link: http://lkml.kernel.org/r/20170120202955.4091-2-bp@alien8.de
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;

</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=c26665ab5c49ad3e142e0f054ca3204f259ba09c'>Diffstat</a> (limited to 'drivers/usb/host/ohci-sa1111.c')</div><table summary='diffstat' class='diffstat'>