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authorStefano Stabellini <stefano.stabellini@eu.citrix.com>2010-12-01 14:51:44 +0000
committerStefano Stabellini <stefano.stabellini@eu.citrix.com>2010-12-02 14:34:25 +0000
commitaf42b8d12f8adec6711cb824549a0edac6a4ae8f (patch)
treee922110d01d85688a03f9ae5d7e31c9f73f2b001 /arch
parente5fc7345412d5e4758fcef55a74354c5cbefd61e (diff)
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xen: fix MSI setup and teardown for PV on HVM guests
When remapping MSIs into pirqs for PV on HVM guests, qemu is responsible for doing the actual mapping and unmapping. We only give qemu the desired pirq number when we ask to do the mapping the first time, after that we should be reading back the pirq number from qemu every time we want to re-enable the MSI. This fixes a bug in xen_hvm_setup_msi_irqs that manifests itself when trying to enable the same MSI for the second time: the old MSI to pirq mapping is still valid at this point but xen_hvm_setup_msi_irqs would try to assign a new pirq anyway. A simple way to reproduce this bug is to assign an MSI capable network card to a PV on HVM guest, if the user brings down the corresponding ethernet interface and up again, Linux would fail to enable MSIs on the device. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/pci/xen.c27
1 files changed, 20 insertions, 7 deletions
diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index d7b5109f7a9..25cd4a07d09 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -70,6 +70,9 @@ static int acpi_register_gsi_xen_hvm(struct device *dev, u32 gsi,
struct xen_pci_frontend_ops *xen_pci_frontend;
EXPORT_SYMBOL_GPL(xen_pci_frontend);
+#define XEN_PIRQ_MSI_DATA (MSI_DATA_TRIGGER_EDGE | \
+ MSI_DATA_LEVEL_ASSERT | (3 << 8) | MSI_DATA_VECTOR(0))
+
static void xen_msi_compose_msg(struct pci_dev *pdev, unsigned int pirq,
struct msi_msg *msg)
{
@@ -83,12 +86,7 @@ static void xen_msi_compose_msg(struct pci_dev *pdev, unsigned int pirq,
MSI_ADDR_REDIRECTION_CPU |
MSI_ADDR_DEST_ID(pirq);
- msg->data =
- MSI_DATA_TRIGGER_EDGE |
- MSI_DATA_LEVEL_ASSERT |
- /* delivery mode reserved */
- (3 << 8) |
- MSI_DATA_VECTOR(0);
+ msg->data = XEN_PIRQ_MSI_DATA;
}
static int xen_hvm_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
@@ -98,8 +96,23 @@ static int xen_hvm_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
struct msi_msg msg;
list_for_each_entry(msidesc, &dev->msi_list, list) {
+ __read_msi_msg(msidesc, &msg);
+ pirq = MSI_ADDR_EXT_DEST_ID(msg.address_hi) |
+ ((msg.address_lo >> MSI_ADDR_DEST_ID_SHIFT) & 0xff);
+ if (xen_irq_from_pirq(pirq) >= 0 && msg.data == XEN_PIRQ_MSI_DATA) {
+ xen_allocate_pirq_msi((type == PCI_CAP_ID_MSIX) ?
+ "msi-x" : "msi", &irq, &pirq, XEN_ALLOC_IRQ);
+ if (irq < 0)
+ goto error;
+ ret = set_irq_msi(irq, msidesc);
+ if (ret < 0)
+ goto error_while;
+ printk(KERN_DEBUG "xen: msi already setup: msi --> irq=%d"
+ " pirq=%d\n", irq, pirq);
+ return 0;
+ }
xen_allocate_pirq_msi((type == PCI_CAP_ID_MSIX) ?
- "msi-x" : "msi", &irq, &pirq);
+ "msi-x" : "msi", &irq, &pirq, (XEN_ALLOC_IRQ | XEN_ALLOC_PIRQ));
if (irq < 0 || pirq < 0)
goto error;
printk(KERN_DEBUG "xen: msi --> irq=%d, pirq=%d\n", irq, pirq);