Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge tag 'for-linus-4.19c-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen fixes from Juergen Gross:
"This contains some minor cleanups and fixes:
- a new knob for controlling scrubbing of pages returned by the Xen
balloon driver to the Xen hypervisor to address a boot performance
issue seen in large guests booted pre-ballooned
- a fix of a regression in the gntdev driver which made it impossible
to use fully virtualized guests (HVM guests) with a 4.19 based dom0
- a fix in Xen cpu hotplug functionality which could be triggered by
wrong admin commands (setting number of active vcpus to 0)
One further note: the patches have all been under test for several
days in another branch. This branch has been rebased in order to avoid
merge conflicts"
* tag 'for-linus-4.19c-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen/gntdev: fix up blockable calls to mn_invl_range_start
xen: fix GCC warning and remove duplicate EVTCHN_ROW/EVTCHN_COL usage
xen: avoid crash in disable_hotplug_cpu
xen/balloon: add runtime control for scrubbing ballooned out pages
xen/manage: don't complain about an empty value in control/sysrq node
+61
-27
+9
Documentation/ABI/stable/sysfs-devices-system-xen_memory
+9
Documentation/ABI/stable/sysfs-devices-system-xen_memory
···
75
75
Description:
76
76
Amount (in KiB) of low (or normal) memory in the
77
77
balloon.
78
+
79
+
What: /sys/devices/system/xen_memory/xen_memory0/scrub_pages
80
+
Date: September 2018
81
+
KernelVersion: 4.20
82
+
Contact: xen-devel@lists.xenproject.org
83
+
Description:
84
+
Control scrubbing pages before returning them to Xen for others domains
85
+
use. Can be set with xen_scrub_pages cmdline
86
+
parameter. Default value controlled with CONFIG_XEN_SCRUB_PAGES_DEFAULT.
+6
Documentation/admin-guide/kernel-parameters.txt
+6
Documentation/admin-guide/kernel-parameters.txt
···
5000
5000
Disables the PV optimizations forcing the HVM guest to
5001
5001
run as generic HVM guest with no PV drivers.
5002
5002
5003
+
xen_scrub_pages= [XEN]
5004
+
Boolean option to control scrubbing pages before giving them back
5005
+
to Xen, for use by other domains. Can be also changed at runtime
5006
+
with /sys/devices/system/xen_memory/xen_memory0/scrub_pages.
5007
+
Default value controlled with CONFIG_XEN_SCRUB_PAGES_DEFAULT.
5008
+
5003
5009
xirc2ps_cs= [NET,PCMCIA]
5004
5010
Format:
5005
5011
<irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
+7
-3
drivers/xen/Kconfig
+7
-3
drivers/xen/Kconfig
···
79
79
This value is used to allocate enough space in internal
80
80
tables needed for physical memory administration.
81
81
82
-
config XEN_SCRUB_PAGES
83
-
bool "Scrub pages before returning them to system"
82
+
config XEN_SCRUB_PAGES_DEFAULT
83
+
bool "Scrub pages before returning them to system by default"
84
84
depends on XEN_BALLOON
85
85
default y
86
86
help
87
87
Scrub pages before returning them to the system for reuse by
88
88
other domains. This makes sure that any confidential data
89
89
is not accidentally visible to other domains. Is it more
90
-
secure, but slightly less efficient.
90
+
secure, but slightly less efficient. This can be controlled with
91
+
xen_scrub_pages=0 parameter and
92
+
/sys/devices/system/xen_memory/xen_memory0/scrub_pages.
93
+
This option only sets the default value.
94
+
91
95
If in doubt, say yes.
92
96
93
97
config XEN_DEV_EVTCHN
+8
-7
drivers/xen/cpu_hotplug.c
+8
-7
drivers/xen/cpu_hotplug.c
···
19
19
20
20
static void disable_hotplug_cpu(int cpu)
21
21
{
22
-
if (cpu_online(cpu)) {
23
-
lock_device_hotplug();
22
+
if (!cpu_is_hotpluggable(cpu))
23
+
return;
24
+
lock_device_hotplug();
25
+
if (cpu_online(cpu))
24
26
device_offline(get_cpu_device(cpu));
25
-
unlock_device_hotplug();
26
-
}
27
-
if (cpu_present(cpu))
27
+
if (!cpu_online(cpu) && cpu_present(cpu)) {
28
28
xen_arch_unregister_cpu(cpu);
29
-
30
-
set_cpu_present(cpu, false);
29
+
set_cpu_present(cpu, false);
30
+
}
31
+
unlock_device_hotplug();
31
32
}
32
33
33
34
static int vcpu_online(unsigned int cpu)
+1
-1
drivers/xen/events/events_base.c
+1
-1
drivers/xen/events/events_base.c
+15
-11
drivers/xen/gntdev.c
+15
-11
drivers/xen/gntdev.c
···
492
492
return true;
493
493
}
494
494
495
-
static void unmap_if_in_range(struct gntdev_grant_map *map,
496
-
unsigned long start, unsigned long end)
495
+
static int unmap_if_in_range(struct gntdev_grant_map *map,
496
+
unsigned long start, unsigned long end,
497
+
bool blockable)
497
498
{
498
499
unsigned long mstart, mend;
499
500
int err;
501
+
502
+
if (!in_range(map, start, end))
503
+
return 0;
504
+
505
+
if (!blockable)
506
+
return -EAGAIN;
500
507
501
508
mstart = max(start, map->vma->vm_start);
502
509
mend = min(end, map->vma->vm_end);
···
515
508
(mstart - map->vma->vm_start) >> PAGE_SHIFT,
516
509
(mend - mstart) >> PAGE_SHIFT);
517
510
WARN_ON(err);
511
+
512
+
return 0;
518
513
}
519
514
520
515
static int mn_invl_range_start(struct mmu_notifier *mn,
···
528
519
struct gntdev_grant_map *map;
529
520
int ret = 0;
530
521
531
-
/* TODO do we really need a mutex here? */
532
522
if (blockable)
533
523
mutex_lock(&priv->lock);
534
524
else if (!mutex_trylock(&priv->lock))
535
525
return -EAGAIN;
536
526
537
527
list_for_each_entry(map, &priv->maps, next) {
538
-
if (in_range(map, start, end)) {
539
-
ret = -EAGAIN;
528
+
ret = unmap_if_in_range(map, start, end, blockable);
529
+
if (ret)
540
530
goto out_unlock;
541
-
}
542
-
unmap_if_in_range(map, start, end);
543
531
}
544
532
list_for_each_entry(map, &priv->freeable_maps, next) {
545
-
if (in_range(map, start, end)) {
546
-
ret = -EAGAIN;
533
+
ret = unmap_if_in_range(map, start, end, blockable);
534
+
if (ret)
547
535
goto out_unlock;
548
-
}
549
-
unmap_if_in_range(map, start, end);
550
536
}
551
537
552
538
out_unlock:
+4
-2
drivers/xen/manage.c
+4
-2
drivers/xen/manage.c
···
280
280
/*
281
281
* The Xenstore watch fires directly after registering it and
282
282
* after a suspend/resume cycle. So ENOENT is no error but
283
-
* might happen in those cases.
283
+
* might happen in those cases. ERANGE is observed when we get
284
+
* an empty value (''), this happens when we acknowledge the
285
+
* request by writing '\0' below.
284
286
*/
285
-
if (err != -ENOENT)
287
+
if (err != -ENOENT && err != -ERANGE)
286
288
pr_err("Error %d reading sysrq code in control/sysrq\n",
287
289
err);
288
290
xenbus_transaction_end(xbt, 1);
+4
drivers/xen/mem-reservation.c
+4
drivers/xen/mem-reservation.c
···
14
14
15
15
#include <xen/interface/memory.h>
16
16
#include <xen/mem-reservation.h>
17
+
#include <linux/moduleparam.h>
18
+
19
+
bool __read_mostly xen_scrub_pages = IS_ENABLED(CONFIG_XEN_SCRUB_PAGES_DEFAULT);
20
+
core_param(xen_scrub_pages, xen_scrub_pages, bool, 0);
17
21
18
22
/*
19
23
* Use one extent per PAGE_SIZE to avoid to break down the page into
+3
drivers/xen/xen-balloon.c
+3
drivers/xen/xen-balloon.c
···
44
44
#include <xen/xenbus.h>
45
45
#include <xen/features.h>
46
46
#include <xen/page.h>
47
+
#include <xen/mem-reservation.h>
47
48
48
49
#define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10))
49
50
···
138
137
static DEVICE_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay);
139
138
static DEVICE_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count);
140
139
static DEVICE_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count);
140
+
static DEVICE_BOOL_ATTR(scrub_pages, 0644, xen_scrub_pages);
141
141
142
142
static ssize_t show_target_kb(struct device *dev, struct device_attribute *attr,
143
143
char *buf)
···
205
203
&dev_attr_max_schedule_delay.attr.attr,
206
204
&dev_attr_retry_count.attr.attr,
207
205
&dev_attr_max_retry_count.attr.attr,
206
+
&dev_attr_scrub_pages.attr.attr,
208
207
NULL
209
208
};
210
209
+4
-3
include/xen/mem-reservation.h
+4
-3
include/xen/mem-reservation.h
···
17
17
18
18
#include <xen/page.h>
19
19
20
+
extern bool xen_scrub_pages;
21
+
20
22
static inline void xenmem_reservation_scrub_page(struct page *page)
21
23
{
22
-
#ifdef CONFIG_XEN_SCRUB_PAGES
23
-
clear_highpage(page);
24
-
#endif
24
+
if (xen_scrub_pages)
25
+
clear_highpage(page);
25
26
}
26
27
27
28
#ifdef CONFIG_XEN_HAVE_PVMMU