xen: Revert commits da72ff5bfcb0 and 72a9b186292d
commit 84d582d236dc1f9085e741affc72e9ba061a67c2 upstream.
Recent discussion (http://marc.info/?l=xen-devel&m=149192184523741)
established that commit 72a9b186292d ("xen: Remove event channel
notification through Xen PCI platform device") (and thus commit
da72ff5bfcb0 ("partially revert "xen: Remove event channel
notification through Xen PCI platform device"")) are unnecessary and,
in fact, prevent HVM guests from booting on Xen releases prior to 4.0
Therefore we revert both of those commits.
The summary of that discussion is below:
Here is the brief summary of the current situation:
Before the offending commit (72a9b186292):
1) INTx does not work because of the reset_watches path.
2) The reset_watches path is only taken if you have Xen > 4.0
3) The Linux Kernel by default will use vector inject if the hypervisor
support. So even INTx does not work no body running the kernel with
Xen > 4.0 would notice. Unless he explicitly disabled this feature
either in the kernel or in Xen (and this can only be disabled by
modifying the code, not user-supported way to do it).
After the offending commit (+ partial revert):
1) INTx is no longer support for HVM (only for PV guests).
2) Any HVM guest The kernel will not boot on Xen < 4.0 which does
not have vector injection support. Since the only other mode
supported is INTx which.
So based on this summary, I think before commit (72a9b186292) we were
in much better position from a user point of view.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Julien Grall <julien.grall@arm.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Ross Lagerwall <ross.lagerwall@citrix.com>
Cc: xen-devel@lists.xenproject.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: Anthony Liguori <aliguori@amazon.com>
Cc: KarimAllah Ahmed <karahmed@amazon.de>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/xen/platform-pci.c b/drivers/xen/platform-pci.c
index b59c9455..cf96666 100644
--- a/drivers/xen/platform-pci.c
+++ b/drivers/xen/platform-pci.c
@@ -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 @@
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 << 56) | /* 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_have_vector_callback)
+ 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 +138,21 @@
platform_mmio = mmio_addr;
platform_mmiolen = mmio_len;
+ if (!xen_have_vector_callback) {
+ 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 +184,9 @@
.name = DRV_NAME,
.probe = platform_pci_probe,
.id_table = platform_pci_tbl,
+#ifdef CONFIG_PM
+ .resume_early = platform_pci_resume,
+#endif
};
static int __init platform_pci_init(void)