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x86: ioapic: add support for explicit EOI 

Some old Linux kernels (upstream before v4.0), or any released RHEL
kernels has problem in sending APIC EOI when IR is enabled. Meanwhile,
many of them only support explicit EOI for IOAPIC, which is only
introduced in IOAPIC version 0x20. This patch provide a way to boost
QEMU IOAPIC to version 0x20, in order for QEMU to correctly receive EOI
messages.

Without boosting IOAPIC version to 0x20, kernels before commit d32932d
("x86/irq: Convert IOAPIC to use hierarchical irqdomain interfaces")
will have trouble enabling both IR and level-triggered interrupt devices
(like e1000).

To upgrade IOAPIC to version 0x20, we need to specify:

  -global ioapic.version=0x20

To be compatible with old systems, 0x11 will still be the default IOAPIC
version. Here 0x11 and 0x20 are the only versions to be supported.

One thing to mention: this patch only applies to emulated IOAPIC. It
does not affect kernel IOAPIC behavior.

Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <1470059959-372-1-git-send-email-peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Peter Xu 2016-08-01 21:59:19 +08:00 committed by Paolo Bonzini
parent f99b86b949
commit 20fd4b7b6d
2 changed files with 23 additions and 3 deletions
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22
hw/intc/ioapic.c
View File

@ -21,6 +21,7 @@
*/
#include "qemu/osdep.h"
#include "qemu/error-report.h"
#include "monitor/monitor.h"
#include "hw/hw.h"
#include "hw/i386/pc.h"
@ -269,7 +270,7 @@ ioapic_mem_read(void *opaque, hwaddr addr, unsigned int size)
val = s->id << IOAPIC_ID_SHIFT;
break;
case IOAPIC_REG_VER:
val = IOAPIC_VERSION |
val = s->version |
((IOAPIC_NUM_PINS - 1) << IOAPIC_VER_ENTRIES_SHIFT);
break;
default:
@ -358,6 +359,13 @@ ioapic_mem_write(void *opaque, hwaddr addr, uint64_t val,
}
}
break;
case IOAPIC_EOI:
/* Explicit EOI is only supported for IOAPIC version 0x20 */
if (size != 4 || s->version != 0x20) {
break;
}
ioapic_eoi_broadcast(val);
break;
}
ioapic_update_kvm_routes(s);
@ -391,6 +399,12 @@ static void ioapic_realize(DeviceState *dev, Error **errp)
{
IOAPICCommonState *s = IOAPIC_COMMON(dev);
if (s->version != 0x11 && s->version != 0x20) {
error_report("IOAPIC only supports version 0x11 or 0x20 "
"(default: 0x11).");
exit(1);
}
memory_region_init_io(&s->io_memory, OBJECT(s), &ioapic_io_ops, s,
"ioapic", 0x1000);
@ -401,6 +415,11 @@ static void ioapic_realize(DeviceState *dev, Error **errp)
qemu_add_machine_init_done_notifier(&s->machine_done);
}
static Property ioapic_properties[] = {
DEFINE_PROP_UINT8("version", IOAPICCommonState, version, 0x11),
DEFINE_PROP_END_OF_LIST(),
};
static void ioapic_class_init(ObjectClass *klass, void *data)
{
IOAPICCommonClass *k = IOAPIC_COMMON_CLASS(klass);
@ -408,6 +427,7 @@ static void ioapic_class_init(ObjectClass *klass, void *data)
k->realize = ioapic_realize;
dc->reset = ioapic_reset_common;
dc->props = ioapic_properties;
}
static const TypeInfo ioapic_info = {

4
include/hw/i386/ioapic_internal.h
View File

@ -29,8 +29,6 @@
#define MAX_IOAPICS 1
#define IOAPIC_VERSION 0x11
#define IOAPIC_LVT_DEST_SHIFT 56
#define IOAPIC_LVT_DEST_IDX_SHIFT 48
#define IOAPIC_LVT_MASKED_SHIFT 16
@ -71,6 +69,7 @@
#define IOAPIC_IOREGSEL 0x00
#define IOAPIC_IOWIN 0x10
#define IOAPIC_EOI 0x40
#define IOAPIC_REG_ID 0x00
#define IOAPIC_REG_VER 0x01
@ -109,6 +108,7 @@ struct IOAPICCommonState {
uint32_t irr;
uint64_t ioredtbl[IOAPIC_NUM_PINS];
Notifier machine_done;
uint8_t version;
};
void ioapic_reset_common(DeviceState *dev);