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x86/jailhouse: Wire up IOAPIC for legacy UART ports

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The typical I/O interrupts in non-root cells are MSI-based. However, the
platform UARTs do not support MSI. In order to run a non-root cell that
shall use one of them, the standard IOAPIC must be registered and 1:1
routing for IRQ 3 and 4 set up.

If an IOAPIC is not available, the boot loader clears standard_ioapic in
the setup data, so registration is skipped. If the guest is not allowed to
to use one of those pins, Jailhouse will simply ignore the access.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: jailhouse-dev@googlegroups.com
Link: https://lkml.kernel.org/r/90d942dda9d48a8046e00bb3c1bb6757c83227be.1511770314.git.jan.kiszka@siemens.com
This commit is contained in:
Jan Kiszka 2017-11-27 09:11:53 +01:00 committed by Thomas Gleixner
parent fd49807682
commit cf878e169d
1 changed files with 21 additions and 0 deletions
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21
arch/x86/kernel/jailhouse.c
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@ -15,6 +15,7 @@
#include <asm/cpu.h>
#include <asm/hypervisor.h>
#include <asm/i8259.h>
#include <asm/irqdomain.h>
#include <asm/reboot.h>
#include <asm/setup.h>
@ -52,6 +53,15 @@ static unsigned long jailhouse_get_tsc(void)
static void __init jailhouse_get_smp_config(unsigned int early)
{
struct ioapic_domain_cfg ioapic_cfg = {
.type = IOAPIC_DOMAIN_STRICT,
.ops = &mp_ioapic_irqdomain_ops,
};
struct mpc_intsrc mp_irq = {
.type = MP_INTSRC,
.irqtype = mp_INT,
.irqflag = MP_IRQPOL_ACTIVE_HIGH | MP_IRQTRIG_EDGE,
};
unsigned int cpu;
if (x2apic_enabled()) {
@ -77,6 +87,17 @@ static void __init jailhouse_get_smp_config(unsigned int early)
}
smp_found_config = 1;
if (setup_data.standard_ioapic) {
mp_register_ioapic(0, 0xfec00000, gsi_top, &ioapic_cfg);
/* Register 1:1 mapping for legacy UART IRQs 3 and 4 */
mp_irq.srcbusirq = mp_irq.dstirq = 3;
mp_save_irq(&mp_irq);
mp_irq.srcbusirq = mp_irq.dstirq = 4;
mp_save_irq(&mp_irq);
}
}
static void jailhouse_no_restart(void)