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Convert the number of MSI IRQs on x86 from a constant to a tunable.

Browse Source 
The number of MSI IRQs still defaults to 512, but it can now be
changed at boot time via the machdep.num_msi_irqs tunable.

Reviewed by:	kib, royger (older version)
Reviewed by:	markj
MFC after:	1 month
Relnotes:	yes
Differential Revision:	https://reviews.freebsd.org/D17977
This commit is contained in:
John Baldwin 2018-11-15 18:37:41 +00:00
parent aaf1f854e1
commit b6b42932db
4 changed files with 25 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
sys/x86/include/intr_machdep.h
View File

@ -58,11 +58,11 @@
* the minimum IRQ value for MSI interrupts to attempt to leave 255
* unused since 255 is used in PCI to indicate an invalid INTx IRQ.
*/
#define NUM_MSI_INTS 512
#define MINIMUM_MSI_INT 256
extern u_int first_msi_irq;
extern u_int num_io_irqs;
extern u_int num_msi_irqs;
/*
* Default base address for MSI messages on x86 platforms.

24
sys/x86/x86/msi.c
View File

@ -44,6 +44,7 @@ __FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
@ -153,6 +154,10 @@ struct pic msi_pic = {
u_int first_msi_irq;
u_int num_msi_irqs = 512;
SYSCTL_UINT(_machdep, OID_AUTO, num_msi_irqs, CTLFLAG_RDTUN, &num_msi_irqs, 0,
"Number of IRQs reserved for MSI and MSI-X interrupts");
#ifdef SMP
/**
* Xen hypervisors prior to 4.6.0 do not properly handle updates to
@ -331,8 +336,13 @@ msi_init(void)
}
#endif
if (num_msi_irqs == 0)
return;
first_msi_irq = max(MINIMUM_MSI_INT, num_io_irqs);
num_io_irqs = first_msi_irq + NUM_MSI_INTS;
if (num_msi_irqs > UINT_MAX - first_msi_irq)
panic("num_msi_irq too high");
num_io_irqs = first_msi_irq + num_msi_irqs;
msi_enabled = 1;
intr_register_pic(&msi_pic);
@ -346,7 +356,7 @@ msi_create_source(void)
u_int irq;
mtx_lock(&msi_lock);
if (msi_last_irq >= NUM_MSI_INTS) {
if (msi_last_irq >= num_msi_irqs) {
mtx_unlock(&msi_lock);
return;
}
@ -390,7 +400,7 @@ msi_alloc(device_t dev, int count, int maxcount, int *irqs)
/* Try to find 'count' free IRQs. */
cnt = 0;
for (i = first_msi_irq; i < first_msi_irq + NUM_MSI_INTS; i++) {
for (i = first_msi_irq; i < first_msi_irq + num_msi_irqs; i++) {
msi = (struct msi_intsrc *)intr_lookup_source(i);
/* End of allocated sources, so break. */
@ -409,7 +419,7 @@ msi_alloc(device_t dev, int count, int maxcount, int *irqs)
/* Do we need to create some new sources? */
if (cnt < count) {
/* If we would exceed the max, give up. */
if (i + (count - cnt) > first_msi_irq + NUM_MSI_INTS) {
if (i + (count - cnt) > first_msi_irq + num_msi_irqs) {
mtx_unlock(&msi_lock);
free(mirqs, M_MSI);
return (ENXIO);
@ -585,7 +595,7 @@ msi_map(int irq, uint64_t *addr, uint32_t *data)
#ifdef ACPI_DMAR
if (!msi->msi_msix) {
for (k = msi->msi_count - 1, i = first_msi_irq; k > 0 &&
i < first_msi_irq + NUM_MSI_INTS; i++) {
i < first_msi_irq + num_msi_irqs; i++) {
if (i == msi->msi_irq)
continue;
msi1 = (struct msi_intsrc *)intr_lookup_source(i);
@ -635,7 +645,7 @@ msix_alloc(device_t dev, int *irq)
mtx_lock(&msi_lock);
/* Find a free IRQ. */
for (i = first_msi_irq; i < first_msi_irq + NUM_MSI_INTS; i++) {
for (i = first_msi_irq; i < first_msi_irq + num_msi_irqs; i++) {
msi = (struct msi_intsrc *)intr_lookup_source(i);
/* End of allocated sources, so break. */
@ -648,7 +658,7 @@ msix_alloc(device_t dev, int *irq)
}
/* Are all IRQs in use? */
if (i == first_msi_irq + NUM_MSI_INTS) {
if (i == first_msi_irq + num_msi_irqs) {
mtx_unlock(&msi_lock);
return (ENXIO);
}

2
sys/x86/xen/xen_intr.c
View File

@ -690,6 +690,8 @@ void
xen_intr_alloc_irqs(void)
{
if (num_io_irqs > UINT_MAX - NR_EVENT_CHANNELS)
panic("IRQ allocation overflow (num_msi_irqs too high?)");
first_evtchn_irq = num_io_irqs;
num_io_irqs += NR_EVENT_CHANNELS;
}

7
sys/x86/xen/xen_msi.c
View File

@ -30,6 +30,7 @@ __FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
@ -57,7 +58,9 @@ xen_msi_init(void)
MPASS(num_io_irqs > 0);
first_msi_irq = min(MINIMUM_MSI_INT, num_io_irqs);
num_io_irqs = first_msi_irq + NUM_MSI_INTS;
if (num_msi_irqs > UINT_MAX - first_msi_irq)
panic("num_msi_irq too high");
num_io_irqs = first_msi_irq + num_msi_irqs;
mtx_init(&msi_lock, "msi", NULL, MTX_DEF);
}
@ -73,7 +76,7 @@ xen_msi_alloc(device_t dev, int count, int maxcount, int *irqs)
mtx_lock(&msi_lock);
/* If we would exceed the max, give up. */
if ((msi_last_irq + count) > NUM_MSI_INTS) {
if (msi_last_irq + count > num_msi_irqs) {
mtx_unlock(&msi_lock);
return (ENXIO);
}