linux/arch/x86/kernel/apic/x2apic_phys.c
Michael S. Tsirkin 0ab711ae6a x86/apic: Implement EIO micro-optimization
We know both register and value for eoi beforehand,
so there's no need to check it and no need to do math
to calculate the msr. Saves instructions/branches
on each EOI when using x2apic.

I looked at the objdump output to verify that the
generated code looks right and actually is shorter.

The real improvemements will be on the KVM guest side
though, those come in a later patch.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: gleb@redhat.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/e019d1a125316f10d3e3a4b2f6bda41473f4fb72.1337184153.git.mst@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-05-18 09:46:09 +02:00

183 lines
4.5 KiB
C

#include <linux/threads.h>
#include <linux/cpumask.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/ctype.h>
#include <linux/init.h>
#include <linux/dmar.h>
#include <asm/smp.h>
#include <asm/x2apic.h>
int x2apic_phys;
static struct apic apic_x2apic_phys;
static int set_x2apic_phys_mode(char *arg)
{
x2apic_phys = 1;
return 0;
}
early_param("x2apic_phys", set_x2apic_phys_mode);
static int x2apic_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
{
if (x2apic_phys)
return x2apic_enabled();
else if ((acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID) &&
(acpi_gbl_FADT.flags & ACPI_FADT_APIC_PHYSICAL) &&
x2apic_enabled()) {
printk(KERN_DEBUG "System requires x2apic physical mode\n");
return 1;
}
else
return 0;
}
static void
__x2apic_send_IPI_mask(const struct cpumask *mask, int vector, int apic_dest)
{
unsigned long query_cpu;
unsigned long this_cpu;
unsigned long flags;
x2apic_wrmsr_fence();
local_irq_save(flags);
this_cpu = smp_processor_id();
for_each_cpu(query_cpu, mask) {
if (apic_dest == APIC_DEST_ALLBUT && this_cpu == query_cpu)
continue;
__x2apic_send_IPI_dest(per_cpu(x86_cpu_to_apicid, query_cpu),
vector, APIC_DEST_PHYSICAL);
}
local_irq_restore(flags);
}
static void x2apic_send_IPI_mask(const struct cpumask *mask, int vector)
{
__x2apic_send_IPI_mask(mask, vector, APIC_DEST_ALLINC);
}
static void
x2apic_send_IPI_mask_allbutself(const struct cpumask *mask, int vector)
{
__x2apic_send_IPI_mask(mask, vector, APIC_DEST_ALLBUT);
}
static void x2apic_send_IPI_allbutself(int vector)
{
__x2apic_send_IPI_mask(cpu_online_mask, vector, APIC_DEST_ALLBUT);
}
static void x2apic_send_IPI_all(int vector)
{
__x2apic_send_IPI_mask(cpu_online_mask, vector, APIC_DEST_ALLINC);
}
static unsigned int x2apic_cpu_mask_to_apicid(const struct cpumask *cpumask)
{
/*
* We're using fixed IRQ delivery, can only return one phys APIC ID.
* May as well be the first.
*/
int cpu = cpumask_first(cpumask);
if ((unsigned)cpu < nr_cpu_ids)
return per_cpu(x86_cpu_to_apicid, cpu);
else
return BAD_APICID;
}
static unsigned int
x2apic_cpu_mask_to_apicid_and(const struct cpumask *cpumask,
const struct cpumask *andmask)
{
int cpu;
/*
* We're using fixed IRQ delivery, can only return one phys APIC ID.
* May as well be the first.
*/
for_each_cpu_and(cpu, cpumask, andmask) {
if (cpumask_test_cpu(cpu, cpu_online_mask))
break;
}
return per_cpu(x86_cpu_to_apicid, cpu);
}
static void init_x2apic_ldr(void)
{
}
static int x2apic_phys_probe(void)
{
if (x2apic_mode && x2apic_phys)
return 1;
return apic == &apic_x2apic_phys;
}
static struct apic apic_x2apic_phys = {
.name = "physical x2apic",
.probe = x2apic_phys_probe,
.acpi_madt_oem_check = x2apic_acpi_madt_oem_check,
.apic_id_valid = x2apic_apic_id_valid,
.apic_id_registered = x2apic_apic_id_registered,
.irq_delivery_mode = dest_Fixed,
.irq_dest_mode = 0, /* physical */
.target_cpus = x2apic_target_cpus,
.disable_esr = 0,
.dest_logical = 0,
.check_apicid_used = NULL,
.check_apicid_present = NULL,
.vector_allocation_domain = x2apic_vector_allocation_domain,
.init_apic_ldr = init_x2apic_ldr,
.ioapic_phys_id_map = NULL,
.setup_apic_routing = NULL,
.multi_timer_check = NULL,
.cpu_present_to_apicid = default_cpu_present_to_apicid,
.apicid_to_cpu_present = NULL,
.setup_portio_remap = NULL,
.check_phys_apicid_present = default_check_phys_apicid_present,
.enable_apic_mode = NULL,
.phys_pkg_id = x2apic_phys_pkg_id,
.mps_oem_check = NULL,
.get_apic_id = x2apic_get_apic_id,
.set_apic_id = x2apic_set_apic_id,
.apic_id_mask = 0xFFFFFFFFu,
.cpu_mask_to_apicid = x2apic_cpu_mask_to_apicid,
.cpu_mask_to_apicid_and = x2apic_cpu_mask_to_apicid_and,
.send_IPI_mask = x2apic_send_IPI_mask,
.send_IPI_mask_allbutself = x2apic_send_IPI_mask_allbutself,
.send_IPI_allbutself = x2apic_send_IPI_allbutself,
.send_IPI_all = x2apic_send_IPI_all,
.send_IPI_self = x2apic_send_IPI_self,
.trampoline_phys_low = DEFAULT_TRAMPOLINE_PHYS_LOW,
.trampoline_phys_high = DEFAULT_TRAMPOLINE_PHYS_HIGH,
.wait_for_init_deassert = NULL,
.smp_callin_clear_local_apic = NULL,
.inquire_remote_apic = NULL,
.read = native_apic_msr_read,
.write = native_apic_msr_write,
.eoi_write = native_apic_msr_eoi_write,
.icr_read = native_x2apic_icr_read,
.icr_write = native_x2apic_icr_write,
.wait_icr_idle = native_x2apic_wait_icr_idle,
.safe_wait_icr_idle = native_safe_x2apic_wait_icr_idle,
};
apic_driver(apic_x2apic_phys);