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xen: implement support for mapping IO APIC interrupts on Xen

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Allow a privileged Xen guest (Dom0) to parse the MADT ACPI interrupt
overrides and register them with the interrupt subsystem.

Also add a Xen specific implementation for bus_config_intr that
registers interrupts on demand for all the vectors less than
FIRST_MSI_INT.

Sponsored by: Citrix Systems R&D

x86/xen/pvcpu_enum.c:
 - Use helper functions from x86/acpica/madt.c in order to parse
   interrupt overrides from the MADT.
 - Walk the MADT and register any interrupt override with the
   interrupt subsystem.

x86/xen/xen_nexus.c:
 - Add a custom bus_config_intr method for Xen that intercepts calls
   to configure unset interrupts and registers them on the fly (if the
   vector is < FIRST_MSI_INT).
This commit is contained in:
Roger Pau Monné 2014-08-04 09:01:21 +00:00
parent f48223fad2
commit c0c19cce9e
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=269513
2 changed files with 117 additions and 0 deletions
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93
sys/x86/xen/pvcpu_enum.c
View File

@ -44,15 +44,25 @@ __FBSDID("$FreeBSD$");
#include <machine/smp.h>
#include <xen/xen-os.h>
#include <xen/xen_intr.h>
#include <xen/hypervisor.h>
#include <xen/interface/vcpu.h>
#include <contrib/dev/acpica/include/acpi.h>
#include <contrib/dev/acpica/include/actables.h>
#include <dev/acpica/acpivar.h>
static int xenpv_probe(void);
static int xenpv_probe_cpus(void);
static int xenpv_setup_local(void);
static int xenpv_setup_io(void);
static ACPI_TABLE_MADT *madt;
static vm_paddr_t madt_physaddr;
static vm_offset_t madt_length;
static struct apic_enumerator xenpv_enumerator = {
"Xen PV",
xenpv_probe,
@ -61,6 +71,55 @@ static struct apic_enumerator xenpv_enumerator = {
xenpv_setup_io
};
/*--------------------- Helper functions to parse MADT -----------------------*/
/*
* Parse an interrupt source override for an ISA interrupt.
*/
static void
madt_parse_interrupt_override(ACPI_MADT_INTERRUPT_OVERRIDE *intr)
{
enum intr_trigger trig;
enum intr_polarity pol;
if (acpi_quirks & ACPI_Q_MADT_IRQ0 && intr->SourceIrq == 0 &&
intr->GlobalIrq == 2) {
if (bootverbose)
printf("MADT: Skipping timer override\n");
return;
}
madt_parse_interrupt_values(intr, &trig, &pol);
/* Register the IRQ with the polarity and trigger mode found. */
xen_register_pirq(intr->GlobalIrq, trig, pol);
}
/*
* Call the handler routine for each entry in the MADT table.
*/
static void
madt_walk_table(acpi_subtable_handler *handler, void *arg)
{
acpi_walk_subtables(madt + 1, (char *)madt + madt->Header.Length,
handler, arg);
}
/*
* Parse interrupt entries.
*/
static void
madt_parse_ints(ACPI_SUBTABLE_HEADER *entry, void *arg __unused)
{
if (entry->Type == ACPI_MADT_TYPE_INTERRUPT_OVERRIDE)
madt_parse_interrupt_override(
(ACPI_MADT_INTERRUPT_OVERRIDE *)entry);
}
/*---------------------------- Xen PV enumerator -----------------------------*/
/*
* This enumerator will only be registered on PVH
*/
@ -105,6 +164,40 @@ xenpv_setup_local(void)
static int
xenpv_setup_io(void)
{
if (xen_initial_domain()) {
int i;
/* Map MADT */
madt_physaddr = acpi_find_table(ACPI_SIG_MADT);
madt = acpi_map_table(madt_physaddr, ACPI_SIG_MADT);
madt_length = madt->Header.Length;
/* Try to initialize ACPI so that we can access the FADT. */
i = acpi_Startup();
if (ACPI_FAILURE(i)) {
printf("MADT: ACPI Startup failed with %s\n",
AcpiFormatException(i));
printf("Try disabling either ACPI or apic support.\n");
panic("Using MADT but ACPI doesn't work");
}
/* Run through the table to see if there are any overrides. */
madt_walk_table(madt_parse_ints, NULL);
/*
* If there was not an explicit override entry for the SCI,
* force it to use level trigger and active-low polarity.
*/
if (!madt_found_sci_override) {
printf(
"MADT: Forcing active-low polarity and level trigger for SCI\n");
xen_register_pirq(AcpiGbl_FADT.SciInterrupt,
INTR_TRIGGER_LEVEL, INTR_POLARITY_LOW);
}
acpi_SetDefaultIntrModel(ACPI_INTR_APIC);
}
return (0);
}

24
sys/x86/xen/xen_nexus.c
View File

@ -36,8 +36,10 @@ __FBSDID("$FreeBSD$");
#include <sys/smp.h>
#include <machine/nexusvar.h>
#include <machine/intr_machdep.h>
#include <xen/xen-os.h>
#include <xen/xen_intr.h>
/*
* Xen nexus(4) driver.
@ -63,11 +65,33 @@ nexus_xen_attach(device_t dev)
return (0);
}
static int
nexus_xen_config_intr(device_t dev, int irq, enum intr_trigger trig,
enum intr_polarity pol)
{
int ret;
/*
* ISA and PCI intline IRQs are not preregistered on Xen, so
* intercept calls to configure those and register them on the fly.
*/
if ((irq < FIRST_MSI_INT) && (intr_lookup_source(irq) == NULL)) {
ret = xen_register_pirq(irq, trig, pol);
if (ret != 0)
return (ret);
nexus_add_irq(irq);
}
return (intr_config_intr(irq, trig, pol));
}
static device_method_t nexus_xen_methods[] = {
/* Device interface */
DEVMETHOD(device_probe, nexus_xen_probe),
DEVMETHOD(device_attach, nexus_xen_attach),
/* INTR */
DEVMETHOD(bus_config_intr, nexus_xen_config_intr),
{ 0, 0 }
};