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Commit 08667577 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'for-linus-4.10-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip 

Pull xen fix from Juergen Gross:
 "A fix for Xen running in nested virtualization environment"

* tag 'for-linus-4.10-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  partially revert "xen: Remove event channel notification through Xen PCI platform device"
parents fb1d8e0e da72ff5b

drivers/xen/platform-pci.c

+71 −0
Original line number Diff line number Diff line
@@ -42,6 +42,7 @@ 
static unsigned long platform_mmio;

static unsigned long platform_mmio_alloc;

static unsigned long platform_mmiolen;

static uint64_t callback_via;



static unsigned long alloc_xen_mmio(unsigned long len)

{
@@ -54,6 +55,51 @@ static unsigned long alloc_xen_mmio(unsigned long len) 
	return addr;

}



static uint64_t get_callback_via(struct pci_dev *pdev)

{

	u8 pin;

	int irq;



	irq = pdev->irq;

	if (irq < 16)

		return irq; /* ISA IRQ */



	pin = pdev->pin;



	/* We don't know the GSI. Specify the PCI INTx line instead. */

	return ((uint64_t)0x01 << HVM_CALLBACK_VIA_TYPE_SHIFT) | /* PCI INTx identifier */

		((uint64_t)pci_domain_nr(pdev->bus) << 32) |

		((uint64_t)pdev->bus->number << 16) |

		((uint64_t)(pdev->devfn & 0xff) << 8) |

		((uint64_t)(pin - 1) & 3);

}



static irqreturn_t do_hvm_evtchn_intr(int irq, void *dev_id)

{

	xen_hvm_evtchn_do_upcall();

	return IRQ_HANDLED;

}



static int xen_allocate_irq(struct pci_dev *pdev)

{

	return request_irq(pdev->irq, do_hvm_evtchn_intr,

			IRQF_NOBALANCING | IRQF_TRIGGER_RISING,

			"xen-platform-pci", pdev);

}



static int platform_pci_resume(struct pci_dev *pdev)

{

	int err;

	if (!xen_pv_domain())

		return 0;

	err = xen_set_callback_via(callback_via);

	if (err) {

		dev_err(&pdev->dev, "platform_pci_resume failure!\n");

		return err;

	}

	return 0;

}



static int platform_pci_probe(struct pci_dev *pdev,

			      const struct pci_device_id *ent)

{
@@ -92,6 +138,28 @@ static int platform_pci_probe(struct pci_dev *pdev, 
	platform_mmio = mmio_addr;

	platform_mmiolen = mmio_len;



	/* 

	 * Xen HVM guests always use the vector callback mechanism.

	 * L1 Dom0 in a nested Xen environment is a PV guest inside in an

	 * HVM environment. It needs the platform-pci driver to get

	 * notifications from L0 Xen, but it cannot use the vector callback

	 * as it is not exported by L1 Xen.

	 */

	if (xen_pv_domain()) {

		ret = xen_allocate_irq(pdev);

		if (ret) {

			dev_warn(&pdev->dev, "request_irq failed err=%d\n", ret);

			goto out;

		}

		callback_via = get_callback_via(pdev);

		ret = xen_set_callback_via(callback_via);

		if (ret) {

			dev_warn(&pdev->dev, "Unable to set the evtchn callback "

					 "err=%d\n", ret);

			goto out;

		}

	}



	max_nr_gframes = gnttab_max_grant_frames();

	grant_frames = alloc_xen_mmio(PAGE_SIZE * max_nr_gframes);

	ret = gnttab_setup_auto_xlat_frames(grant_frames);
@@ -123,6 +191,9 @@ static struct pci_driver platform_driver = { 
	.name =           DRV_NAME,

	.probe =          platform_pci_probe,

	.id_table =       platform_pci_tbl,

#ifdef CONFIG_PM

	.resume_early =   platform_pci_resume,

#endif

};



builtin_pci_driver(platform_driver);