* Re: [PATCH v4 2/5] mm/zswap: Factor writeback loop out of shrink_worker()
From: Hao Jia @ 2026-06-25 11:28 UTC (permalink / raw)
To: Yosry Ahmed
Cc: akpm, tj, hannes, shakeel.butt, mhocko, mkoutny, nphamcs,
chengming.zhou, muchun.song, roman.gushchin, linux-mm,
linux-kernel, linux-doc, Hao Jia
In-Reply-To: <CAO9r8zPSZLaqLXw87V3q4tZa8WD7xCympKqfLMLB+o-++GksJQ@mail.gmail.com>
On 2026/6/25 01:00, Yosry Ahmed wrote:
> On Wed, Jun 24, 2026 at 4:55 AM Hao Jia <jiahao.kernel@gmail.com> wrote:
>>
>>
>>
>> On 2026/6/23 07:36, Yosry Ahmed wrote:
>>
>>
>> Perhaps something like this?
>>
>> struct zswap_shrink_state {
>> int attempts;
>> int failures;
>> bool stop;
>> };
>>
>> static bool zswap_shrink_no_candidate(struct zswap_shrink_state *s)
>> {
>> if (!s->attempts && ++s->failures == MAX_RECLAIM_RETRIES)
>> return true;
>>
>> s->attempts = 0;
>> return false;
>> }
>>
>> static long zswap_shrink_one(struct mem_cgroup *memcg,
>> struct zswap_shrink_state *s)
>> {
>> long shrunk;
>>
>> shrunk = shrink_memcg(memcg, NR_ZSWAP_WB_BATCH);
>> if (shrunk == -ENOENT)
>> return 0;
>>
>> s->attempts++;
>> if (shrunk <= 0 && ++s->failures == MAX_RECLAIM_RETRIES)
>> s->stop = true;
>
> Do we need 'stop' or can we just return a value here to indicate that
> we should stop (e.g. -EBUSY)?
>
Perhaps we could return -EAGAIN instead of -EBUSY? This would align with
the semantics of the memory.reclaim interface, which returns -EAGAIN
when it reclaims fewer bytes than requested.
>>
>> return shrunk;
>> }
>>
>> static void shrink_worker(struct work_struct *w)
>> {
>> struct zswap_shrink_state s = {};
>> unsigned long thr;
>>
>> /* Reclaim down to the accept threshold */
>> thr = zswap_accept_thr_pages();
>>
>> while (zswap_total_pages() > thr) {
>> struct mem_cgroup *memcg;
>>
>> cond_resched();
>>
>> memcg = zswap_iter_global();
>> if (!memcg) {
>> if (zswap_shrink_no_candidate(&s))
>> break;
>> continue;
>> }
>>
>> zswap_shrink_one(memcg, &s);
>> /* Drop the extra reference taken by the iterator. */
>> mem_cgroup_put(memcg);
>> if (s.stop)
>> break;
>> }
>> }
>
> I think splitting the shrink/retry logic over 2 functions makes it
> more difficult to follow, so yeah I think fold
> zswap_shrink_no_candidate() into zswap_shrink_one(). Then the callers
> only need to iterate memcgs (depending on the context) and call
> zswap_shrink_one() for each of them.
So, something like this?
/* Track progress of a memcg-tree writeback walk. */
struct zswap_shrink_state {
int attempts;
int failures;
};
/*
* Take one step of a memcg-tree writeback walk driven by the caller's
* iterator, and fold the result into @s, the retry bookkeeping shared
* across steps. @memcg is the iterator's current memcg, or NULL once
* it has wrapped around after a full pass over the tree.
*
* The function returns -EAGAIN to signal the caller to abort the walk
* after encountering the following conditions MAX_RECLAIM_RETRIES times:
* - No writeback-candidate memcgs were found in a memcg tree walk.
* - Shrinking a writeback-candidate memcg failed.
*
* Return: The number of compressed bytes written back (>= 0), or -EAGAIN
* once the retry budget is exhausted and the caller should abort the walk.
*/
static long zswap_shrink_one(struct mem_cgroup *memcg,
struct zswap_shrink_state *s)
{
long shrunk;
/*
* If the iterator has completed a full pass, update the shrink state
* and check whether we should keep going.
*/
if (!memcg) {
/*
* Continue shrinking without incrementing failures if we found
* candidate memcgs in the last tree walk.
*/
if (!s->attempts && ++s->failures == MAX_RECLAIM_RETRIES)
return -EAGAIN;
s->attempts = 0;
return 0;
}
shrunk = shrink_memcg(memcg, NR_ZSWAP_WB_BATCH);
/*
* There are no writeback-candidate pages in the memcg. This is not an
* issue as long as we can find another memcg with pages in zswap. Skip
* this without incrementing attempts and failures.
*/
if (shrunk == -ENOENT)
return 0;
s->attempts++;
if (shrunk <= 0 && ++s->failures == MAX_RECLAIM_RETRIES)
return -EAGAIN;
return shrunk;
}
static void shrink_worker(struct work_struct *w)
{
struct zswap_shrink_state s = {};
unsigned long thr;
/* Reclaim down to the accept threshold */
thr = zswap_accept_thr_pages();
while (zswap_total_pages() > thr) {
struct mem_cgroup *memcg;
long ret;
cond_resched();
memcg = zswap_iter_global();
ret = zswap_shrink_one(memcg, &s);
/* drop the extra reference taken by zswap_iter_global() */
mem_cgroup_put(memcg);
if (ret == -EAGAIN)
break;
}
}
^ permalink raw reply
* Re: [PATCH v4 0/2] tracing: Move non-trace_printk prototypes into trace_controls.h
From: Jani Nikula @ 2026-06-25 11:05 UTC (permalink / raw)
To: Steven Rostedt, linux-kernel, linux-trace-kernel
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Linus Torvalds, Sebastian Andrzej Siewior, John Ogness,
Thomas Gleixner, Peter Zijlstra, Julia Lawall, Yury Norov,
linux-doc, linux-kbuild, linuxppc-dev, dri-devel, linux-stm32,
linux-arm-kernel, linux-rdma, linux-usb, linux-ext4, linux-nfs,
kvm, intel-gfx
In-Reply-To: <20260625104007.041432666@kernel.org>
On Thu, 25 Jun 2026, Steven Rostedt <rostedt@kernel.org> wrote:
> Remove trace_printk.h by creating a trace_controls.h for those places that
> need access to tracing prototypes like tracing_off() and for the places that
> need trace_printk() directly, to have it included directly.
>
> Changse since v3: https://lore.kernel.org/all/20260624081806.120105649@kernel.org/
>
> - Always include trace_controls.h in rcu.h (kernel test robot)
>
> There are other configs that may include tracing_off() in rcu.h besides
> the one that had the include of trace_controls.h. Just always include
> it in that header to be safe.
>
> Steven Rostedt (2):
> tracing: Move non-trace_printk prototypes into trace_controls.h
> tracing: Remove trace_printk.h from kernel.h
>
> ----
> arch/powerpc/kvm/book3s_xics.c | 1 +
> arch/powerpc/xmon/xmon.c | 1 +
> arch/s390/kernel/ipl.c | 1 +
> arch/s390/kernel/machine_kexec.c | 1 +
> drivers/gpu/drm/i915/gt/intel_gtt.h | 1 +
> drivers/gpu/drm/i915/i915_gem.h | 2 ++
For the i915 parts,
Acked-by: Jani Nikula <jani.nikula@intel.com>
for merging via whichever tree.
> drivers/hwtracing/stm/dummy_stm.c | 1 +
> drivers/infiniband/hw/hfi1/trace_dbg.h | 1 +
> drivers/tty/sysrq.c | 1 +
> drivers/usb/early/xhci-dbc.c | 1 +
> fs/ext4/inline.c | 1 +
> include/linux/ftrace.h | 2 ++
> include/linux/kernel.h | 1 -
> include/linux/sunrpc/debug.h | 1 +
> include/linux/trace_controls.h | 54 ++++++++++++++++++++++++++++++++
> include/linux/trace_printk.h | 56 ++--------------------------------
> kernel/debug/debug_core.c | 1 +
> kernel/panic.c | 1 +
> kernel/rcu/rcu.h | 1 +
> kernel/rcu/rcutorture.c | 1 +
> kernel/trace/ring_buffer_benchmark.c | 1 +
> kernel/trace/trace.h | 1 +
> kernel/trace/trace_benchmark.c | 1 +
> lib/sys_info.c | 1 +
> samples/fprobe/fprobe_example.c | 1 +
> samples/ftrace/ftrace-direct-too.c | 1 -
> samples/trace_printk/trace-printk.c | 1 +
> 27 files changed, 82 insertions(+), 55 deletions(-)
> create mode 100644 include/linux/trace_controls.h
--
Jani Nikula, Intel
^ permalink raw reply
* Re: [PATCH v16 04/14] lib: kstrtox: add initial value to _parse_integer_limit()
From: Jonathan Cameron @ 2026-06-25 10:58 UTC (permalink / raw)
To: Rodrigo Alencar
Cc: rodrigo.alencar, linux-kernel, linux-iio, devicetree, linux-doc,
linux, David Lechner, Andy Shevchenko, Lars-Peter Clausen,
Michael Hennerich, Rob Herring, Krzysztof Kozlowski, Conor Dooley,
Jonathan Corbet, Andrew Morton, Petr Mladek, Steven Rostedt,
Andy Shevchenko, Rasmus Villemoes, Sergey Senozhatsky, Shuah Khan
In-Reply-To: <ssrckqgv3rqpfgxwpx4ca3m5m2mp3frxs6sd673chvsorhsjiq@63t3eosivg3a>
On Thu, 25 Jun 2026 08:30:07 +0100
Rodrigo Alencar <455.rodrigo.alencar@gmail.com> wrote:
> On 24/06/26 15:54, Jonathan Cameron wrote:
> > On Sun, 14 Jun 2026 21:00:44 +0100
> > Jonathan Cameron <jic23@kernel.org> wrote:
> >
> > > On Thu, 4 Jun 2026 11:09:33 +0100
> > > Rodrigo Alencar <455.rodrigo.alencar@gmail.com> wrote:
> > >
> > > > On 26/06/04 10:58AM, Rodrigo Alencar via B4 Relay wrote:
> > > > > From: Rodrigo Alencar <rodrigo.alencar@analog.com>
> > > > >
> > > > > Add init parameter to _parse_integer_limit() that defines an initial
> > > > > value for the accumulated result when parsing an 64-bit integer. The
> > > > > new function prototype is adjusted so that the _parse_integer() macros
> > > > > stay consistent allowing for one more argument, which defaults to 0.
> > > >
> > > > ...
> > > >
> > > > > noinline
> > > > > unsigned int _parse_integer_limit(const char *s, unsigned int base, unsigned long long *p,
> > > > > - size_t max_chars)
> > > > > + size_t max_chars, unsigned long long init)
> > > > > {
> > > > > unsigned long long res;
> > > > > unsigned int rv;
> > > > >
> > > > > - res = 0;
> > > > > + res = init;
> > > >
> > > > This might generate conflict, as the code around have changed in linux-next.
> > > > It is an easy fix though.
> > > >
> > > Thanks for the heads up. Hopefully that will all fall out when I rebase testing
> > > on rc1 once that is out.
> > I've done a mid merge cycle rebase as the char-misc branches have merged.
> > So this should be resolve on my testing branch now.
>
> https://lore.kernel.org/oe-kbuild-all/202606250230.etPGuolf-lkp@intel.com/
>
> Apparently, the documentation header now includes parameter descriptions.
> The new one is missing.
I'm snowed under for next few days so if you have time to spin me a fixup patch
that I can just apply that would be great.
If not I'll get to it next week probably.
Jonathan
>
^ permalink raw reply
* Re: [PATCH v8 24/46] KVM: guest_memfd: Make in-place conversion the default
From: Yan Zhao @ 2026-06-25 10:57 UTC (permalink / raw)
To: Sean Christopherson, Ackerley Tng, aik, andrew.jones, binbin.wu,
brauner, chao.p.peng, david, jmattson, jthoughton, michael.roth,
oupton, pankaj.gupta, qperret, rick.p.edgecombe, rientjes,
shivankg, steven.price, tabba, willy, wyihan, forkloop, pratyush,
suzuki.poulose, aneesh.kumar, liam, Paolo Bonzini,
Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, x86,
H. Peter Anvin, Steven Rostedt, Masami Hiramatsu,
Mathieu Desnoyers, Jonathan Corbet, Shuah Khan, Shuah Khan,
Vishal Annapurve, Andrew Morton, Chris Li, Kairui Song,
Kemeng Shi, Nhat Pham, Barry Song, Axel Rasmussen, Yuanchu Xie,
Wei Xu, Youngjun Park, Qi Zheng, Shakeel Butt, Kiryl Shutsemau,
Baoquan He, Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <ajyJhZcgfYFtGfS2@yzhao56-desk.sh.intel.com>
On Thu, Jun 25, 2026 at 09:51:01AM +0800, Yan Zhao wrote:
> On Wed, Jun 24, 2026 at 05:41:58PM -0700, Sean Christopherson wrote:
> > On Wed, Jun 24, 2026, Ackerley Tng wrote:
> > > Yan Zhao <yan.y.zhao@intel.com> writes:
> > > > With gmem_in_place_conversion=true, userspace can create guest_memfd without the
> > > > MMAP flag. In such cases, shared memory is allocated from different backends.
> > > > This means this module parameter only enables per-gmem memory attribute and does
> > > > not guarantee that gmem in-place conversion will actually occur.
> >
> > KVM module params are pretty much always about what KVM supports, not what is
> > guaranteed to happen.
> >
> > - enable_mmio_caching doesn't guarantee there will actually be MMIO SPTEs,
> > because maybe the guest never accesses emulated MMIO.
> > - enable_pmu doesn't guarantee VMs will get a PMU, because userspace may elect
> > not to advertise one.
> > - and so on and so forth...
> >
> > Yes, there's a small mental jump to get from "KVM supports in-place conversion"
> > to "I need to set memory attributes on the guest_memfd instance, not the VM",
> > but I don't see that as a big hurdle, certainly not in the long term. And once
> > the VMM code is written, I really do think most people are going to care about
> > whether or not KVM supports in-place conversion, not where PRIVATE is tracked.
> Sorry, I just saw this mail after posting my reply in [1].
>
> I'm ok with gmem_in_place_conversion=true just means KVM supports in-place
> conversion, while we can still create VMs with shared memory not from gmem.
Or what about "allow_gmem_in_place_conversion" ?
> Though it still feels a bit odd to require TDX huge pages to depend on
> gmem_in_place_conversion=true when shared memory is not currently allocated from
> gmem, it should become more natural over time once gmem supports in-place
> conversions for huge page.
>
> [1] https://lore.kernel.org/all/ajyCn0PnFtQK+Nka@yzhao56-desk.sh.intel.com
>
>
> > > > To avoid confusion, could we rename this module parameter to something more
> > > > accurate, such as gmem_memory_attribute?
> > >
> > > I asked Sean about this after getting some fixes off list. Sean said
> > > gmem_in_place_conversion is named for a host admin to use, and something
> > > like gmem_memory_attributes is too much implementation details for the
> > > admin.
> > >
> > > Sean, would you reconsider since Yan also asked? If the admin compiled
> > > the kernel knowing what CONFIG_KVM_VM_MEMORY_ATTRIBUTES means, then the
> > > admin would also be able to use a param like gmem_memory_attributes?
> >
> > No, because it's not all memory attributes, it's very specifically the PRIVATE
> > attribute that will get moved to guest_memfd. I don't want to pick a name that
> > will become stale and confusing when RWX attributes come along. The RWX bits
> > will be per-VM, while PRIVATE will be per-guest_memfd.
^ permalink raw reply
* Re: [PATCH net-next] Documentation: networking: Add a test plan for ethtool pause validation
From: Maxime Chevallier @ 2026-06-25 10:46 UTC (permalink / raw)
To: Andrew Lunn
Cc: Jakub Kicinski, davem, Eric Dumazet, Paolo Abeni, Simon Horman,
Russell King, Heiner Kallweit, Jonathan Corbet, Shuah Khan,
Oleksij Rempel, Vladimir Oltean, Florian Fainelli,
thomas.petazzoni, netdev, linux-kernel, linux-doc
In-Reply-To: <b7de216a-fd1a-42a0-8711-d822a1ad9319@lunn.ch>
Hi Andrew,
On 5/29/26 14:59, Andrew Lunn wrote:
(This discussion was a while ago, but this bit of context should be enough)
> But we also need to consider that for some APIs, we have decided that
> a configuration can be set now, which does not actually apply in our
> current conditions, but it will be stored away for when conditions
> change and it is applicable. The half duplex case could fit that. When
> the link is currently half duplex, you can configure pause, but you
> don't expect it to actually change the current behaviour. It only
> kicks in when the link renegotiates to full duplex sometime in the
> future. We have to also consider this the other way around. The link
> is full duplex and pause is configured by the user. Something happens
> with the LP and the link renegotiates to half duplex. The local end
> should not throw away the configuration, it simply cannot apply it
> given the current situation.
I'm writing the test description for HD with a better formatting, so the
HD test wouldn't be about "are we using pause stuff while in HD" as it
doesn't make sense, but rather "do we correctly store the pause settings
aside for later".
I'm realising that we don't really have an API to report the *true* in-use pause
settings. Taking HD as an example :
# ethtool -s eth2 duplex half
[588209.379363] mvpp2 f4000000.ethernet eth2: Link is Up - 100Mbps/Half - flow control off
# ethtool eth2
[...]
Supported pause frame use: Symmetric Receive-only
Advertised pause frame use: Symmetric Receive-only
Link partner advertised pause frame use: Symmetric Receive-only
# ethtool -a eth2
Autonegotiate: on
RX: off
TX: off
RX negotiated: on
TX negotiated: on
Sure, pause and HD don't make sense, however what I find confusing to some
extent is that the only place we have information about the *actual* pause
settings is the "link is Up" log in dmesg.
Maybe the problem in the above situation is that whoever advertises
half-duplex only modes should also not advertise pause ?
Still, I'm wondering if we should even care about all that actually, HD and
Pause are incompatible, and that's it. If you have any thought on this, let
me know.
Maxime
^ permalink raw reply
* [PATCH v4 1/2] tracing: Move non-trace_printk prototypes into trace_controls.h
From: Steven Rostedt @ 2026-06-25 10:40 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Linus Torvalds, Sebastian Andrzej Siewior, John Ogness,
Thomas Gleixner, Peter Zijlstra, Julia Lawall, Yury Norov,
linux-doc, linux-kbuild, linuxppc-dev, dri-devel, linux-stm32,
linux-arm-kernel, linux-rdma, linux-usb, linux-ext4, linux-nfs,
kvm, intel-gfx
In-Reply-To: <20260625104007.041432666@kernel.org>
From: Steven Rostedt <rostedt@goodmis.org>
Remove the prototypes of the code that is not associated with
trace_printk() from trace_printk.h.
These control functions as well as ftrace_dump() and trace_dump_stack()
are used in cases where things go wrong. The main use case is to do a
trace_dump_stack(); tracing_off(); ftrace_dump(); in a place that detected
that something went wrong, whereas, trace_printk() is added to normal code
during debugging and removed before committing upstream. The dump code is
fine to keep in production.
Suggested-by: Yury Norov <yury.norov@gmail.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
Changes since v3: https://patch.msgid.link/20260624081948.147764194@kernel.org
- Move include out of #if statement in rcu.h
kernel test robot found other configs that could require the
control functions in rcu.h. Just always include it in that file.
arch/powerpc/xmon/xmon.c | 1 +
arch/s390/kernel/ipl.c | 1 +
arch/s390/kernel/machine_kexec.c | 1 +
drivers/gpu/drm/i915/i915_gem.h | 1 +
drivers/tty/sysrq.c | 1 +
include/linux/trace_controls.h | 54 ++++++++++++++++++++++++++++++++
include/linux/trace_printk.h | 51 ------------------------------
kernel/debug/debug_core.c | 1 +
kernel/panic.c | 1 +
kernel/rcu/rcu.h | 1 +
kernel/rcu/rcutorture.c | 1 +
kernel/trace/trace.h | 1 +
kernel/trace/trace_benchmark.c | 1 +
lib/sys_info.c | 1 +
14 files changed, 66 insertions(+), 51 deletions(-)
create mode 100644 include/linux/trace_controls.h
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index cb3a3244ae6f..2135f319e0dd 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -27,6 +27,7 @@
#include <linux/highmem.h>
#include <linux/security.h>
#include <linux/debugfs.h>
+#include <linux/trace_controls.h>
#include <asm/ptrace.h>
#include <asm/smp.h>
diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index 3c346b02ceb9..baac66cc4de4 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -22,6 +22,7 @@
#include <linux/debug_locks.h>
#include <linux/vmalloc.h>
#include <linux/secure_boot.h>
+#include <linux/trace_controls.h>
#include <asm/asm-extable.h>
#include <asm/machine.h>
#include <asm/diag.h>
diff --git a/arch/s390/kernel/machine_kexec.c b/arch/s390/kernel/machine_kexec.c
index baeb3dcfc1c8..33f9a89eb3ad 100644
--- a/arch/s390/kernel/machine_kexec.c
+++ b/arch/s390/kernel/machine_kexec.c
@@ -12,6 +12,7 @@
#include <linux/delay.h>
#include <linux/reboot.h>
#include <linux/ftrace.h>
+#include <linux/trace_controls.h>
#include <linux/debug_locks.h>
#include <linux/cpufeature.h>
#include <asm/guarded_storage.h>
diff --git a/drivers/gpu/drm/i915/i915_gem.h b/drivers/gpu/drm/i915/i915_gem.h
index 20b3cb29cfff..1da8fb61c09e 100644
--- a/drivers/gpu/drm/i915/i915_gem.h
+++ b/drivers/gpu/drm/i915/i915_gem.h
@@ -116,6 +116,7 @@ int i915_gem_open(struct drm_i915_private *i915, struct drm_file *file);
#endif
#if IS_ENABLED(CONFIG_DRM_I915_TRACE_GEM)
+#include <linux/trace_controls.h>
#define GEM_TRACE(...) trace_printk(__VA_ARGS__)
#define GEM_TRACE_ERR(...) do { \
pr_err(__VA_ARGS__); \
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index c2e4b31b699a..d3f72dc430b8 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -324,6 +324,7 @@ static const struct sysrq_key_op sysrq_showstate_blocked_op = {
};
#ifdef CONFIG_TRACING
+#include <linux/trace_controls.h>
#include <linux/ftrace.h>
static void sysrq_ftrace_dump(u8 key)
diff --git a/include/linux/trace_controls.h b/include/linux/trace_controls.h
new file mode 100644
index 000000000000..995b97e963b4
--- /dev/null
+++ b/include/linux/trace_controls.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_TRACE_CONTROLS_H
+#define _LINUX_TRACE_CONTROLS_H
+
+
+/*
+ * General tracing related utility functions - trace_printk(),
+ * tracing_on/tracing_off and tracing_start()/tracing_stop
+ *
+ * Use tracing_on/tracing_off when you want to quickly turn on or off
+ * tracing. It simply enables or disables the recording of the trace events.
+ * This also corresponds to the user space /sys/kernel/tracing/tracing_on
+ * file, which gives a means for the kernel and userspace to interact.
+ * Place a tracing_off() in the kernel where you want tracing to end.
+ * From user space, examine the trace, and then echo 1 > tracing_on
+ * to continue tracing.
+ *
+ * tracing_stop/tracing_start has slightly more overhead. It is used
+ * by things like suspend to ram where disabling the recording of the
+ * trace is not enough, but tracing must actually stop because things
+ * like calling smp_processor_id() may crash the system.
+ *
+ * Most likely, you want to use tracing_on/tracing_off.
+ */
+enum ftrace_dump_mode {
+ DUMP_NONE,
+ DUMP_ALL,
+ DUMP_ORIG,
+ DUMP_PARAM,
+};
+
+#ifdef CONFIG_TRACING
+void tracing_on(void);
+void tracing_off(void);
+int tracing_is_on(void);
+void tracing_snapshot(void);
+void tracing_snapshot_alloc(void);
+void tracing_start(void);
+void tracing_stop(void);
+void trace_dump_stack(int skip);
+void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
+#else
+static inline void tracing_start(void) { }
+static inline void tracing_stop(void) { }
+static inline void tracing_on(void) { }
+static inline void tracing_off(void) { }
+static inline int tracing_is_on(void) { return 0; }
+static inline void tracing_snapshot(void) { }
+static inline void tracing_snapshot_alloc(void) { }
+static inline void trace_dump_stack(int skip) { }
+static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
+#endif
+
+#endif /* _LINUX_TRACE_CONTROLS_H */
diff --git a/include/linux/trace_printk.h b/include/linux/trace_printk.h
index 3d54f440dccf..a488ea9e9f85 100644
--- a/include/linux/trace_printk.h
+++ b/include/linux/trace_printk.h
@@ -7,43 +7,7 @@
#include <linux/stddef.h>
#include <linux/stringify.h>
-/*
- * General tracing related utility functions - trace_printk(),
- * tracing_on/tracing_off and tracing_start()/tracing_stop
- *
- * Use tracing_on/tracing_off when you want to quickly turn on or off
- * tracing. It simply enables or disables the recording of the trace events.
- * This also corresponds to the user space /sys/kernel/tracing/tracing_on
- * file, which gives a means for the kernel and userspace to interact.
- * Place a tracing_off() in the kernel where you want tracing to end.
- * From user space, examine the trace, and then echo 1 > tracing_on
- * to continue tracing.
- *
- * tracing_stop/tracing_start has slightly more overhead. It is used
- * by things like suspend to ram where disabling the recording of the
- * trace is not enough, but tracing must actually stop because things
- * like calling smp_processor_id() may crash the system.
- *
- * Most likely, you want to use tracing_on/tracing_off.
- */
-
-enum ftrace_dump_mode {
- DUMP_NONE,
- DUMP_ALL,
- DUMP_ORIG,
- DUMP_PARAM,
-};
-
#ifdef CONFIG_TRACING
-void tracing_on(void);
-void tracing_off(void);
-int tracing_is_on(void);
-void tracing_snapshot(void);
-void tracing_snapshot_alloc(void);
-
-extern void tracing_start(void);
-extern void tracing_stop(void);
-
static inline __printf(1, 2)
void ____trace_printk_check_format(const char *fmt, ...)
{
@@ -149,8 +113,6 @@ int __trace_printk(unsigned long ip, const char *fmt, ...);
extern int __trace_bputs(unsigned long ip, const char *str);
extern int __trace_puts(unsigned long ip, const char *str);
-extern void trace_dump_stack(int skip);
-
/*
* The double __builtin_constant_p is because gcc will give us an error
* if we try to allocate the static variable to fmt if it is not a
@@ -173,19 +135,7 @@ __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
extern __printf(2, 0) int
__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
-
-extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
#else
-static inline void tracing_start(void) { }
-static inline void tracing_stop(void) { }
-static inline void trace_dump_stack(int skip) { }
-
-static inline void tracing_on(void) { }
-static inline void tracing_off(void) { }
-static inline int tracing_is_on(void) { return 0; }
-static inline void tracing_snapshot(void) { }
-static inline void tracing_snapshot_alloc(void) { }
-
static inline __printf(1, 2)
int trace_printk(const char *fmt, ...)
{
@@ -196,7 +146,6 @@ ftrace_vprintk(const char *fmt, va_list ap)
{
return 0;
}
-static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
#endif /* CONFIG_TRACING */
#endif
diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index b276504c1c6b..f9c83a470c98 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -27,6 +27,7 @@
#define pr_fmt(fmt) "KGDB: " fmt
+#include <linux/trace_controls.h>
#include <linux/pid_namespace.h>
#include <linux/clocksource.h>
#include <linux/serial_core.h>
diff --git a/kernel/panic.c b/kernel/panic.c
index 213725b612aa..1415e910371d 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -9,6 +9,7 @@
* This function is used through-out the kernel (including mm and fs)
* to indicate a major problem.
*/
+#include <linux/trace_controls.h>
#include <linux/debug_locks.h>
#include <linux/sched/debug.h>
#include <linux/interrupt.h>
diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index fa6d30ce73d1..735a80df0b30 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -12,6 +12,7 @@
#include <linux/slab.h>
#include <trace/events/rcu.h>
+#include <linux/trace_controls.h>
/*
* Grace-period counter management.
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 882a158ada7b..76bf0184b267 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -39,6 +39,7 @@
#include <linux/srcu.h>
#include <linux/slab.h>
#include <linux/trace_clock.h>
+#include <linux/trace_controls.h>
#include <asm/byteorder.h>
#include <linux/torture.h>
#include <linux/vmalloc.h>
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 80fe152af1dd..2537c33ddd49 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -22,6 +22,7 @@
#include <linux/ctype.h>
#include <linux/once_lite.h>
#include <linux/ftrace_regs.h>
+#include <linux/trace_controls.h>
#include <linux/llist.h>
#include "pid_list.h"
diff --git a/kernel/trace/trace_benchmark.c b/kernel/trace/trace_benchmark.c
index e19c32f2a938..69cc39008c36 100644
--- a/kernel/trace/trace_benchmark.c
+++ b/kernel/trace/trace_benchmark.c
@@ -3,6 +3,7 @@
#include <linux/module.h>
#include <linux/kthread.h>
#include <linux/trace_clock.h>
+#include <linux/trace_controls.h>
#define CREATE_TRACE_POINTS
#include "trace_benchmark.h"
diff --git a/lib/sys_info.c b/lib/sys_info.c
index f32a06ec9ed4..e3c9ca05601b 100644
--- a/lib/sys_info.c
+++ b/lib/sys_info.c
@@ -8,6 +8,7 @@
#include <linux/ftrace.h>
#include <linux/nmi.h>
#include <linux/sched/debug.h>
+#include <linux/trace_controls.h>
#include <linux/string.h>
#include <linux/sysctl.h>
--
2.53.0
^ permalink raw reply related
* [PATCH v4 2/2] tracing: Remove trace_printk.h from kernel.h
From: Steven Rostedt @ 2026-06-25 10:40 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Linus Torvalds, Sebastian Andrzej Siewior, John Ogness,
Thomas Gleixner, Peter Zijlstra, Julia Lawall, Yury Norov,
linux-doc, linux-kbuild, linuxppc-dev, dri-devel, linux-stm32,
linux-arm-kernel, linux-rdma, linux-usb, linux-ext4, linux-nfs,
kvm, intel-gfx
In-Reply-To: <20260625104007.041432666@kernel.org>
From: Steven Rostedt <rostedt@goodmis.org>
There have been complaints about trace_printk.h causing more build time
for being in kernel.h if it changes. There is also an effort to clean up
kernel.h to have it not include unneeded header files. Move trace_printk.h
out of kernel.h and place it in the headers and C files that use it.
Link: https://lore.kernel.org/all/CAHk-=wikCBeVFjVXiY4o-oepdbjAoir5+TcAgtL12c4u1TpZLQ@mail.gmail.com/
Suggested-by: Yury Norov <yury.norov@gmail.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
arch/powerpc/kvm/book3s_xics.c | 1 +
drivers/gpu/drm/i915/gt/intel_gtt.h | 1 +
drivers/gpu/drm/i915/i915_gem.h | 1 +
drivers/hwtracing/stm/dummy_stm.c | 1 +
drivers/infiniband/hw/hfi1/trace_dbg.h | 1 +
drivers/usb/early/xhci-dbc.c | 1 +
fs/ext4/inline.c | 1 +
include/linux/ftrace.h | 2 ++
include/linux/kernel.h | 1 -
include/linux/sunrpc/debug.h | 1 +
include/linux/trace_printk.h | 5 +++--
kernel/trace/ring_buffer_benchmark.c | 1 +
samples/fprobe/fprobe_example.c | 1 +
samples/ftrace/ftrace-direct-too.c | 1 -
samples/trace_printk/trace-printk.c | 1 +
15 files changed, 16 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/kvm/book3s_xics.c b/arch/powerpc/kvm/book3s_xics.c
index 74a44fa702b0..ef5eb596a56e 100644
--- a/arch/powerpc/kvm/book3s_xics.c
+++ b/arch/powerpc/kvm/book3s_xics.c
@@ -26,6 +26,7 @@
#if 1
#define XICS_DBG(fmt...) do { } while (0)
#else
+#include <linux/trace_printk.h>
#define XICS_DBG(fmt...) trace_printk(fmt)
#endif
diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.h b/drivers/gpu/drm/i915/gt/intel_gtt.h
index b54ee4f25af1..f6f223090760 100644
--- a/drivers/gpu/drm/i915/gt/intel_gtt.h
+++ b/drivers/gpu/drm/i915/gt/intel_gtt.h
@@ -35,6 +35,7 @@
#define I915_GFP_ALLOW_FAIL (GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN)
#if IS_ENABLED(CONFIG_DRM_I915_TRACE_GTT)
+#include <linux/trace_printk.h>
#define GTT_TRACE(...) trace_printk(__VA_ARGS__)
#else
#define GTT_TRACE(...)
diff --git a/drivers/gpu/drm/i915/i915_gem.h b/drivers/gpu/drm/i915/i915_gem.h
index 1da8fb61c09e..f490052e8964 100644
--- a/drivers/gpu/drm/i915/i915_gem.h
+++ b/drivers/gpu/drm/i915/i915_gem.h
@@ -117,6 +117,7 @@ int i915_gem_open(struct drm_i915_private *i915, struct drm_file *file);
#if IS_ENABLED(CONFIG_DRM_I915_TRACE_GEM)
#include <linux/trace_controls.h>
+#include <linux/trace_printk.h>
#define GEM_TRACE(...) trace_printk(__VA_ARGS__)
#define GEM_TRACE_ERR(...) do { \
pr_err(__VA_ARGS__); \
diff --git a/drivers/hwtracing/stm/dummy_stm.c b/drivers/hwtracing/stm/dummy_stm.c
index 38528ffdc0b3..7c5e48ebfb9f 100644
--- a/drivers/hwtracing/stm/dummy_stm.c
+++ b/drivers/hwtracing/stm/dummy_stm.c
@@ -8,6 +8,7 @@
*/
#undef DEBUG
+#include <linux/trace_printk.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
diff --git a/drivers/infiniband/hw/hfi1/trace_dbg.h b/drivers/infiniband/hw/hfi1/trace_dbg.h
index 58304b91380f..30df5e246586 100644
--- a/drivers/infiniband/hw/hfi1/trace_dbg.h
+++ b/drivers/infiniband/hw/hfi1/trace_dbg.h
@@ -103,6 +103,7 @@ __hfi1_trace_def(IOCTL);
*/
#ifdef HFI1_EARLY_DBG
+#include <linux/trace_printk.h>
#define hfi1_dbg_early(fmt, ...) \
trace_printk(fmt, ##__VA_ARGS__)
#else
diff --git a/drivers/usb/early/xhci-dbc.c b/drivers/usb/early/xhci-dbc.c
index 41118bba9197..955c73bd601f 100644
--- a/drivers/usb/early/xhci-dbc.c
+++ b/drivers/usb/early/xhci-dbc.c
@@ -30,6 +30,7 @@ static struct xdbc_state xdbc;
static bool early_console_keep;
#ifdef XDBC_TRACE
+#include <linux/trace_printk.h>
#define xdbc_trace trace_printk
#else
static inline void xdbc_trace(const char *fmt, ...) { }
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 8045e4ff270c..0eff4a0c6a6c 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -934,6 +934,7 @@ static int ext4_da_convert_inline_data_to_extent(struct address_space *mapping,
}
#ifdef INLINE_DIR_DEBUG
+#include <linux/trace_printk.h>
void ext4_show_inline_dir(struct inode *dir, struct buffer_head *bh,
void *inline_start, int inline_size)
{
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 02bc5027523a..b5336a81e619 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -8,6 +8,8 @@
#define _LINUX_FTRACE_H
#include <linux/trace_recursion.h>
+#include <linux/trace_controls.h>
+#include <linux/trace_printk.h>
#include <linux/trace_clock.h>
#include <linux/jump_label.h>
#include <linux/kallsyms.h>
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index e5570a16cbb1..e87a40fbd152 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -31,7 +31,6 @@
#include <linux/build_bug.h>
#include <linux/sprintf.h>
#include <linux/static_call_types.h>
-#include <linux/trace_printk.h>
#include <linux/util_macros.h>
#include <linux/wordpart.h>
diff --git a/include/linux/sunrpc/debug.h b/include/linux/sunrpc/debug.h
index ab61bed2f7af..7524f5d82fba 100644
--- a/include/linux/sunrpc/debug.h
+++ b/include/linux/sunrpc/debug.h
@@ -29,6 +29,7 @@ extern unsigned int nlm_debug;
# define ifdebug(fac) if (unlikely(rpc_debug & RPCDBG_##fac))
# if IS_ENABLED(CONFIG_SUNRPC_DEBUG_TRACE)
+# include <linux/trace_printk.h>
# define __sunrpc_printk(fmt, ...) trace_printk(fmt, ##__VA_ARGS__)
# else
# define __sunrpc_printk(fmt, ...) printk(KERN_DEFAULT fmt, ##__VA_ARGS__)
diff --git a/include/linux/trace_printk.h b/include/linux/trace_printk.h
index a488ea9e9f85..74ce4f8995c4 100644
--- a/include/linux/trace_printk.h
+++ b/include/linux/trace_printk.h
@@ -1,11 +1,12 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_TRACE_PRINTK_H
#define _LINUX_TRACE_PRINTK_H
+#if !defined(__ASSEMBLY__) && !defined(__GENKSYMS__) && !defined(BUILD_VDSO)
-#include <linux/compiler_attributes.h>
#include <linux/instruction_pointer.h>
#include <linux/stddef.h>
#include <linux/stringify.h>
+#include <linux/stdarg.h>
#ifdef CONFIG_TRACING
static inline __printf(1, 2)
@@ -147,5 +148,5 @@ ftrace_vprintk(const char *fmt, va_list ap)
return 0;
}
#endif /* CONFIG_TRACING */
-
+#endif /* !defined(__ASSEMBLY__) && !defined(__GENKSYMS__) && !defined(BUILD_VDSO) */
#endif
diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c
index 593e3b59e42e..2bb25caebb75 100644
--- a/kernel/trace/ring_buffer_benchmark.c
+++ b/kernel/trace/ring_buffer_benchmark.c
@@ -5,6 +5,7 @@
* Copyright (C) 2009 Steven Rostedt <srostedt@redhat.com>
*/
#include <linux/ring_buffer.h>
+#include <linux/trace_printk.h>
#include <linux/completion.h>
#include <linux/kthread.h>
#include <uapi/linux/sched/types.h>
diff --git a/samples/fprobe/fprobe_example.c b/samples/fprobe/fprobe_example.c
index bfe98ce826f3..de81b9b4ca7d 100644
--- a/samples/fprobe/fprobe_example.c
+++ b/samples/fprobe/fprobe_example.c
@@ -12,6 +12,7 @@
#define pr_fmt(fmt) "%s: " fmt, __func__
+#include <linux/trace_printk.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/fprobe.h>
diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c
index bf2411aa6fd7..159190f4103f 100644
--- a/samples/ftrace/ftrace-direct-too.c
+++ b/samples/ftrace/ftrace-direct-too.c
@@ -1,6 +1,5 @@
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/module.h>
-
#include <linux/mm.h> /* for handle_mm_fault() */
#include <linux/ftrace.h>
#if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32)
diff --git a/samples/trace_printk/trace-printk.c b/samples/trace_printk/trace-printk.c
index cfc159580263..ff37aeb8523e 100644
--- a/samples/trace_printk/trace-printk.c
+++ b/samples/trace_printk/trace-printk.c
@@ -1,4 +1,5 @@
// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/trace_printk.h>
#include <linux/module.h>
#include <linux/kthread.h>
#include <linux/irq_work.h>
--
2.53.0
^ permalink raw reply related
* [PATCH v4 0/2] tracing: Move non-trace_printk prototypes into trace_controls.h
From: Steven Rostedt @ 2026-06-25 10:40 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Linus Torvalds, Sebastian Andrzej Siewior, John Ogness,
Thomas Gleixner, Peter Zijlstra, Julia Lawall, Yury Norov,
linux-doc, linux-kbuild, linuxppc-dev, dri-devel, linux-stm32,
linux-arm-kernel, linux-rdma, linux-usb, linux-ext4, linux-nfs,
kvm, intel-gfx
Remove trace_printk.h by creating a trace_controls.h for those places that
need access to tracing prototypes like tracing_off() and for the places that
need trace_printk() directly, to have it included directly.
Changse since v3: https://lore.kernel.org/all/20260624081806.120105649@kernel.org/
- Always include trace_controls.h in rcu.h (kernel test robot)
There are other configs that may include tracing_off() in rcu.h besides
the one that had the include of trace_controls.h. Just always include
it in that header to be safe.
Steven Rostedt (2):
tracing: Move non-trace_printk prototypes into trace_controls.h
tracing: Remove trace_printk.h from kernel.h
----
arch/powerpc/kvm/book3s_xics.c | 1 +
arch/powerpc/xmon/xmon.c | 1 +
arch/s390/kernel/ipl.c | 1 +
arch/s390/kernel/machine_kexec.c | 1 +
drivers/gpu/drm/i915/gt/intel_gtt.h | 1 +
drivers/gpu/drm/i915/i915_gem.h | 2 ++
drivers/hwtracing/stm/dummy_stm.c | 1 +
drivers/infiniband/hw/hfi1/trace_dbg.h | 1 +
drivers/tty/sysrq.c | 1 +
drivers/usb/early/xhci-dbc.c | 1 +
fs/ext4/inline.c | 1 +
include/linux/ftrace.h | 2 ++
include/linux/kernel.h | 1 -
include/linux/sunrpc/debug.h | 1 +
include/linux/trace_controls.h | 54 ++++++++++++++++++++++++++++++++
include/linux/trace_printk.h | 56 ++--------------------------------
kernel/debug/debug_core.c | 1 +
kernel/panic.c | 1 +
kernel/rcu/rcu.h | 1 +
kernel/rcu/rcutorture.c | 1 +
kernel/trace/ring_buffer_benchmark.c | 1 +
kernel/trace/trace.h | 1 +
kernel/trace/trace_benchmark.c | 1 +
lib/sys_info.c | 1 +
samples/fprobe/fprobe_example.c | 1 +
samples/ftrace/ftrace-direct-too.c | 1 -
samples/trace_printk/trace-printk.c | 1 +
27 files changed, 82 insertions(+), 55 deletions(-)
create mode 100644 include/linux/trace_controls.h
^ permalink raw reply
* Re: [PATCH 1/2] cgroup/dmem: add per-region event counters
From: Hongfu Li @ 2026-06-25 10:21 UTC (permalink / raw)
To: Natalie Vock, tj
Cc: cgroups, corbet, dev, dri-devel, hannes, linux-doc, linux-kernel,
mkoutny, mripard, skhan, hongfu.li
In-Reply-To: <b549422c-7c35-434d-ad4a-49a4676970ac@gmx.de>
Hi,
On 6/25/26 4:57 PM, Natalie Vock wrote:
> Hi,
>
> On 6/25/26 04:10, Hongfu Li wrote:
>> Hi, Tejun
>> Thanks for the review comments.
>>
>>>> Add dmem.events to report hierarchical low/max event counts per DMEM
>>>> region. Increment counters on dmem.max allocation failures and
>>>> dmem.low protection events. The file is available for non-root
>>>> cgroups
>>>> only.
>>>
>>> Please don't double space in descs or comments. Also, maybe it's
>>> obvious but
>>> it'd help if you list why and how this is useful. Why do we want to add
>>> this?
>>
>> I'll fix the double spacing in the commit message and comments.
>>
>> As for the motivation: dmem already exposes per-region limits and
>> current
>> usage, but not how often those limits actually matter at runtime.
>> Without
>> event counters, it's hard to tell whether allocation failures come from
>> this cgroup, a parent limit, or pressure elsewhere in the hierarchy.
>> dmem.events provides that visibility for tuning dmem.low/dmem.max and
>> diagnosing recurring device memory pressure.
>
> Shouldn't you be able to deduce this rather trivially from just
> looking at the current usage together with the low/max limits you
> already set? I'm not sure I really see anything this events file
> provides that analysis of current usage and set limits doesn't? If
> your usage is highly variable, the separately-developed dmem.peak file
> might also suit your needs, but still, not sure what you can do with
> dmem.events that you can't already do with these tools.
Thanks for the question.
Besides exposing counters, dmem.events notifies userspace on changes via
cgroup_file_notify(). This allows tools to monitor limit-related events
(for example, allocation failures or low-protection fallbacks)
asynchronously,
without the need to periodically poll dmem.current against the limits.
While
you could infer some conditions from current usage and limits, polling is
inefficient and cannot capture transient events in real time. dmem.peak only
records the highest usage, not these specific events.
So dmem.events provides both lower overhead and richer, actionable
information.
Best regards,
Hongfu
^ permalink raw reply
* Re: [PATCH] Documentation: dev-tools: scripts/container prefers Podman
From: Coiby Xu @ 2026-06-25 10:05 UTC (permalink / raw)
To: Guillaume Tucker
Cc: linux-doc, Jonathan Corbet, Shuah Khan,
open list:DOCUMENTATION PROCESS, open list
In-Reply-To: <df2fd6ae-69bd-42e6-bf28-ad8103b4189f@gtucker.io>
On Wed, Jun 24, 2026 at 11:02:49PM +0200, Guillaume Tucker wrote:
>Hi Coiby,
Hi Guillaume,
>
>On 24/06/2026 03:38, Coiby Xu wrote:
>> Obviously scripts/container prefers Podman over Docker. Putting podman
>> before docker also makes it consistent with following parts of the doc
>> and the help text of the tool.
>>
>> Signed-off-by: Coiby Xu <coiby.xu@gmail.com>
>> ---
>> Documentation/dev-tools/container.rst | 6 +++---
>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/Documentation/dev-tools/container.rst b/Documentation/dev-tools/container.rst
>> index 452415b64662..9e23f79d5ae1 100644
>> --- a/Documentation/dev-tools/container.rst
>> +++ b/Documentation/dev-tools/container.rst
>> @@ -40,7 +40,7 @@ Available options:
>>
>> ``-r, --runtime RUNTIME``
>>
>> - Container runtime name. Supported runtimes: ``docker``, ``podman``.
>> + Container runtime name. Supported runtimes: ``podman``, ``docker``.
>>
>> If not specified, the first one found on the system will be used
>> i.e. Podman if present, otherwise Docker.
>> @@ -75,8 +75,8 @@ working directory and adjust the user and group id as needed.
>>
>> The container image which would typically include a compiler toolchain is
>> provided by the user and selected via the ``-i`` option. The container runtime
>> -can be selected with the ``-r`` option, which can be either ``docker`` or
>> -``podman``. If none is specified, the first one found on the system will be
>> +can be selected with the ``-r`` option, which can be either ``podman`` or
>> +``docker``. If none is specified, the first one found on the system will be
>> used while giving priority to Podman. Support for other runtimes may be added
>> later depending on their popularity among users.
>>
>
>It's a very subtle tweak but it does help avoid some confusion.
>
>Reviewed-by: Guillaume Tucker <gtucker@gtucker.io>
Thanks for taking time to reviewing the patch!
>
>Thanks,
>Guillaume
>
--
Best regards,
Coiby
^ permalink raw reply
* Re: [PATCH v8 46/46] KVM: selftests: Update private memory exits test to work with per-gmem attributes
From: Fuad Tabba @ 2026-06-25 9:56 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-46-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:32, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Sean Christopherson <seanjc@google.com>
>
> Skip setting memory to private in the private memory exits test when using
> per-gmem memory attributes, as memory is initialized to private by default
> for guest_memfd, and using vm_mem_set_private() on a guest_memfd instance
> requires creating guest_memfd with GUEST_MEMFD_FLAG_MMAP (which is totally
> doable, but would need to be conditional and is ultimately unnecessary).
>
> Expect an emulated MMIO instead of a memory fault exit when attributes are
> per-gmem, as deleting the memslot effectively drops the private status,
> i.e. the GPA becomes shared and thus supports emulated MMIO.
>
> Skip the "memslot not private" test entirely, as private vs. shared state
> for x86 software-protected VMs comes from the memory attributes themselves,
> and so when doing in-place conversions there can never be a disconnect
> between the expected and actual states.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Cheers,
/fuad
> ---
> .../selftests/kvm/x86/private_mem_kvm_exits_test.c | 36 ++++++++++++++++++----
> 1 file changed, 30 insertions(+), 6 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/x86/private_mem_kvm_exits_test.c b/tools/testing/selftests/kvm/x86/private_mem_kvm_exits_test.c
> index 10db9fe6d9063..70ed16066c63e 100644
> --- a/tools/testing/selftests/kvm/x86/private_mem_kvm_exits_test.c
> +++ b/tools/testing/selftests/kvm/x86/private_mem_kvm_exits_test.c
> @@ -62,8 +62,9 @@ static void test_private_access_memslot_deleted(void)
>
> virt_map(vm, EXITS_TEST_GVA, EXITS_TEST_GPA, EXITS_TEST_NPAGES);
>
> - /* Request to access page privately */
> - vm_mem_set_private(vm, EXITS_TEST_GPA, EXITS_TEST_SIZE);
> + /* Request to access page privately. */
> + if (!kvm_has_gmem_attributes)
> + vm_mem_set_private(vm, EXITS_TEST_GPA, EXITS_TEST_SIZE);
>
> pthread_create(&vm_thread, NULL,
> (void *(*)(void *))run_vcpu_get_exit_reason,
> @@ -74,10 +75,26 @@ static void test_private_access_memslot_deleted(void)
> pthread_join(vm_thread, &thread_return);
> exit_reason = (u32)(u64)thread_return;
>
> - TEST_ASSERT_EQ(exit_reason, KVM_EXIT_MEMORY_FAULT);
> - TEST_ASSERT_EQ(vcpu->run->memory_fault.flags, KVM_MEMORY_EXIT_FLAG_PRIVATE);
> - TEST_ASSERT_EQ(vcpu->run->memory_fault.gpa, EXITS_TEST_GPA);
> - TEST_ASSERT_EQ(vcpu->run->memory_fault.size, EXITS_TEST_SIZE);
> + /*
> + * If attributes are tracked per-gmem, deleting the memslot that points
> + * at the gmem instance effectively makes the memory shared, and so the
> + * read should trigger emulated MMIO.
> + *
> + * If attributes are tracked per-VM, deleting the memslot shouldn't
> + * affect the private attribute, and so KVM should generate a memory
> + * fault exit (emulated MMIO on private GPAs is disallowed).
> + */
> + if (kvm_has_gmem_attributes) {
> + TEST_ASSERT_EQ(exit_reason, KVM_EXIT_MMIO);
> + TEST_ASSERT_EQ(vcpu->run->mmio.phys_addr, EXITS_TEST_GPA);
> + TEST_ASSERT_EQ(vcpu->run->mmio.len, sizeof(u64));
> + TEST_ASSERT_EQ(vcpu->run->mmio.is_write, false);
> + } else {
> + TEST_ASSERT_EQ(exit_reason, KVM_EXIT_MEMORY_FAULT);
> + TEST_ASSERT_EQ(vcpu->run->memory_fault.flags, KVM_MEMORY_EXIT_FLAG_PRIVATE);
> + TEST_ASSERT_EQ(vcpu->run->memory_fault.gpa, EXITS_TEST_GPA);
> + TEST_ASSERT_EQ(vcpu->run->memory_fault.size, EXITS_TEST_SIZE);
> + }
>
> kvm_vm_free(vm);
> }
> @@ -88,6 +105,13 @@ static void test_private_access_memslot_not_private(void)
> struct kvm_vcpu *vcpu;
> u32 exit_reason;
>
> + /*
> + * Accessing non-private memory as private with a software-protected VM
> + * isn't possible when doing in-place conversions.
> + */
> + if (kvm_has_gmem_attributes)
> + return;
> +
> vm = vm_create_shape_with_one_vcpu(protected_vm_shape, &vcpu,
> guest_repeatedly_read);
>
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH v8 45/46] KVM: selftests: Update private_mem_conversions_test to mmap() guest_memfd
From: Fuad Tabba @ 2026-06-25 9:43 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-45-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:32, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Ackerley Tng <ackerleytng@google.com>
>
> Update the private memory conversions selftest to also test conversions
> that are done "in-place" via per-guest_memfd memory attributes. In-place
> conversions require the host to be able to mmap() the guest_memfd so that
> the host and guest can share the same backing physical memory.
>
> This includes several updates, that are conditioned on the system
> supporting per-guest_memfd attributes (kvm_has_gmem_attributes):
>
> 1. Set up guest_memfd requesting MMAP and INIT_SHARED.
>
> 2. With in-place conversions, the host's mapping points directly to the
> guest's memory. When the guest converts a region to private, host access
> to that region is blocked. Update the test to expect a SIGBUS when
> attempting to access the host virtual address (HVA) of private memory.
>
> 3. Use vm_mem_set_memory_attributes(), which chooses how to set memory
> attributes based on whether kvm_has_gmem_attributes.
>
> Restrict the test to using VM_MEM_SRC_SHMEM because guest_memfd's required
> mmap() flags and page sizes happens to align with those of
> VM_MEM_SRC_SHMEM. As long as VM_MEM_SRC_SHMEM is used for src_type,
> vm_mem_add() works as intended.
>
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
> Co-developed-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Cheers,
/fuad
> ---
> .../kvm/x86/private_mem_conversions_test.c | 44 ++++++++++++++++++----
> 1 file changed, 36 insertions(+), 8 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c b/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
> index 289ad10063fca..4308c67952310 100644
> --- a/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
> +++ b/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
> @@ -306,9 +306,12 @@ static void handle_exit_hypercall(struct kvm_vcpu *vcpu)
> if (do_fallocate)
> vm_guest_mem_fallocate(vm, gpa, size, map_shared);
>
> - if (set_attributes)
> - vm_set_memory_attributes(vm, gpa, size,
> - map_shared ? 0 : KVM_MEMORY_ATTRIBUTE_PRIVATE);
> + if (set_attributes) {
> + u64 attrs = map_shared ? 0 : KVM_MEMORY_ATTRIBUTE_PRIVATE;
> +
> + vm_mem_set_memory_attributes(vm, gpa, size, attrs);
> + }
> +
> run->hypercall.ret = 0;
> }
>
> @@ -352,8 +355,20 @@ static void *__test_mem_conversions(void *__vcpu)
> size_t nr_bytes = min_t(size_t, vm->page_size, size - i);
> u8 *hva = addr_gpa2hva(vm, gpa + i);
>
> - /* In all cases, the host should observe the shared data. */
> - memcmp_h(hva, gpa + i, uc.args[3], nr_bytes);
> + /*
> + * When using per-guest_memfd memory attributes,
> + * i.e. in-place conversion, host accesses will
> + * point at guest memory and should SIGBUS when
> + * guest memory is private. When using per-VM
> + * attributes, i.e. separate backing for shared
> + * vs. private, the host should always observe
> + * the shared data.
> + */
> + if (kvm_has_gmem_attributes &&
> + uc.args[0] == SYNC_PRIVATE)
> + TEST_EXPECT_SIGBUS(READ_ONCE(*hva));
> + else
> + memcmp_h(hva, gpa + i, uc.args[3], nr_bytes);
>
> /* For shared, write the new pattern to guest memory. */
> if (uc.args[0] == SYNC_SHARED)
> @@ -382,6 +397,7 @@ static void test_mem_conversions(enum vm_mem_backing_src_type src_type, u32 nr_v
> const size_t slot_size = memfd_size / nr_memslots;
> struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
> pthread_t threads[KVM_MAX_VCPUS];
> + u64 gmem_flags;
> struct kvm_vm *vm;
> int memfd, i;
>
> @@ -397,12 +413,17 @@ static void test_mem_conversions(enum vm_mem_backing_src_type src_type, u32 nr_v
>
> vm_enable_cap(vm, KVM_CAP_EXIT_HYPERCALL, (1 << KVM_HC_MAP_GPA_RANGE));
>
> - memfd = vm_create_guest_memfd(vm, memfd_size, 0);
> + if (kvm_has_gmem_attributes)
> + gmem_flags = GUEST_MEMFD_FLAG_MMAP | GUEST_MEMFD_FLAG_INIT_SHARED;
> + else
> + gmem_flags = 0;
> +
> + memfd = vm_create_guest_memfd(vm, memfd_size, gmem_flags);
>
> for (i = 0; i < nr_memslots; i++)
> vm_mem_add(vm, src_type, BASE_DATA_GPA + slot_size * i,
> BASE_DATA_SLOT + i, slot_size / vm->page_size,
> - KVM_MEM_GUEST_MEMFD, memfd, slot_size * i, 0);
> + KVM_MEM_GUEST_MEMFD, memfd, slot_size * i, gmem_flags);
>
> for (i = 0; i < nr_vcpus; i++) {
> gpa_t gpa = BASE_DATA_GPA + i * per_cpu_size;
> @@ -452,17 +473,24 @@ static void usage(const char *cmd)
>
> int main(int argc, char *argv[])
> {
> - enum vm_mem_backing_src_type src_type = DEFAULT_VM_MEM_SRC;
> + enum vm_mem_backing_src_type src_type;
> u32 nr_memslots = 1;
> u32 nr_vcpus = 1;
> int opt;
>
> TEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_SW_PROTECTED_VM));
>
> + src_type = kvm_has_gmem_attributes ? VM_MEM_SRC_SHMEM :
> + DEFAULT_VM_MEM_SRC;
> +
> while ((opt = getopt(argc, argv, "hm:s:n:")) != -1) {
> switch (opt) {
> case 's':
> src_type = parse_backing_src_type(optarg);
> + TEST_ASSERT(!kvm_has_gmem_attributes ||
> + src_type == VM_MEM_SRC_SHMEM,
> + "Testing in-place conversions, only %s mem_type supported\n",
> + vm_mem_backing_src_alias(VM_MEM_SRC_SHMEM)->name);
> break;
> case 'n':
> nr_vcpus = atoi_positive("nr_vcpus", optarg);
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH v8 44/46] KVM: selftests: Make TEST_EXPECT_SIGBUS thread-safe
From: Fuad Tabba @ 2026-06-25 9:30 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-44-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:32, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Ackerley Tng <ackerleytng@google.com>
>
> The TEST_EXPECT_SIGBUS macro is not thread-safe as it uses a global
> sigjmp_buf and installs a global SIGBUS signal handler. If multiple threads
> execute the macro concurrently, they will race on installing the signal
> handler and stomp on other threads' jump buffers, leading to incorrect test
> behavior.
>
> Make TEST_EXPECT_SIGBUS thread-safe with the following changes:
>
> Share the KVM tests' global signal handler. sigaction() applies to all
> threads; without sharing a global signal handler, one thread may have
> removed the signal handler that another thread added, hence leading to
> unexpected signals.
>
> The alternative of layering signal handlers was considered, but calling
> sigaction() within TEST_EXPECT_SIGBUS() necessarily creates a race. To
> avoid adding new setup and teardown routines to do sigaction() and keep
> usage of TEST_EXPECT_SIGBUS() simple, share the KVM tests' global signal
> handler.
>
> Opportunistically rename report_unexpected_signal to
> catchall_signal_handler.
>
> To continue to only expect SIGBUS within specific regions of code, use a
> thread-specific variable, expecting_sigbus, to replace installing and
> removing signal handlers.
>
> Make the execution environment for the thread, sigjmp_buf, a
> thread-specific variable.
>
> As part of TEST_EXPECT_SIGBUS(), assert the prerequisite for this setup,
> that the current signal handler is the catchall_signal_handler.
>
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Cheers,
/fuad
> ---
> tools/testing/selftests/kvm/include/test_util.h | 32 +++++++++++++------------
> tools/testing/selftests/kvm/lib/kvm_util.c | 18 ++++++++++----
> tools/testing/selftests/kvm/lib/test_util.c | 7 ------
> 3 files changed, 30 insertions(+), 27 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h
> index 51287fac8138a..bd75162ec868d 100644
> --- a/tools/testing/selftests/kvm/include/test_util.h
> +++ b/tools/testing/selftests/kvm/include/test_util.h
> @@ -82,21 +82,23 @@ do { \
> __builtin_unreachable(); \
> } while (0)
>
> -extern sigjmp_buf expect_sigbus_jmpbuf;
> -void expect_sigbus_handler(int signum);
> -
> -#define TEST_EXPECT_SIGBUS(action) \
> -do { \
> - struct sigaction sa_old, sa_new = { \
> - .sa_handler = expect_sigbus_handler, \
> - }; \
> - \
> - sigaction(SIGBUS, &sa_new, &sa_old); \
> - if (sigsetjmp(expect_sigbus_jmpbuf, 1) == 0) { \
> - action; \
> - TEST_FAIL("'%s' should have triggered SIGBUS", #action); \
> - } \
> - sigaction(SIGBUS, &sa_old, NULL); \
> +extern __thread sigjmp_buf expect_sigbus_jmpbuf;
> +extern __thread volatile sig_atomic_t expecting_sigbus;
> +extern void catchall_signal_handler(int signum);
> +
> +#define TEST_EXPECT_SIGBUS(action) \
> +do { \
> + struct sigaction __sa = {}; \
> + \
> + TEST_ASSERT_EQ(sigaction(SIGBUS, NULL, &__sa), 0); \
> + TEST_ASSERT_EQ(__sa.sa_handler, &catchall_signal_handler); \
> + \
> + expecting_sigbus = true; \
> + if (sigsetjmp(expect_sigbus_jmpbuf, 1) == 0) { \
> + action; \
> + TEST_FAIL("'%s' should have triggered SIGBUS", #action);\
> + } \
> + expecting_sigbus = false; \
> } while (0)
>
> size_t parse_size(const char *size);
> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> index 6b304e8a0e0d5..b4f104436875b 100644
> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> @@ -2292,13 +2292,20 @@ __weak void kvm_selftest_arch_init(void)
> {
> }
>
> -static void report_unexpected_signal(int signum)
> +__thread sigjmp_buf expect_sigbus_jmpbuf;
> +__thread volatile sig_atomic_t expecting_sigbus;
> +
> +void catchall_signal_handler(int signum)
> {
> + switch (signum) {
> + case SIGBUS: {
> + if (expecting_sigbus)
> + siglongjmp(expect_sigbus_jmpbuf, 1);
> +
> + TEST_FAIL("Unexpected SIGBUS (%d)\n", signum);
> + }
> #define KVM_CASE_SIGNUM(sig) \
> case sig: TEST_FAIL("Unexpected " #sig " (%d)\n", signum)
> -
> - switch (signum) {
> - KVM_CASE_SIGNUM(SIGBUS);
> KVM_CASE_SIGNUM(SIGSEGV);
> KVM_CASE_SIGNUM(SIGILL);
> KVM_CASE_SIGNUM(SIGFPE);
> @@ -2310,12 +2317,13 @@ static void report_unexpected_signal(int signum)
> void __attribute((constructor)) kvm_selftest_init(void)
> {
> struct sigaction sig_sa = {
> - .sa_handler = report_unexpected_signal,
> + .sa_handler = catchall_signal_handler,
> };
>
> /* Tell stdout not to buffer its content. */
> setbuf(stdout, NULL);
>
> + expecting_sigbus = false;
> sigaction(SIGBUS, &sig_sa, NULL);
> sigaction(SIGSEGV, &sig_sa, NULL);
> sigaction(SIGILL, &sig_sa, NULL);
> diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c
> index bab1bd2b775b6..30eb701e4becd 100644
> --- a/tools/testing/selftests/kvm/lib/test_util.c
> +++ b/tools/testing/selftests/kvm/lib/test_util.c
> @@ -18,13 +18,6 @@
>
> #include "test_util.h"
>
> -sigjmp_buf expect_sigbus_jmpbuf;
> -
> -void __attribute__((used)) expect_sigbus_handler(int signum)
> -{
> - siglongjmp(expect_sigbus_jmpbuf, 1);
> -}
> -
> /*
> * Random number generator that is usable from guest code. This is the
> * Park-Miller LCG using standard constants.
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* [PATCH] Documentation: landlock: Document fs.resolve_unix audit blocker
From: Doehyun Baek @ 2026-06-25 9:28 UTC (permalink / raw)
To: Mickaël Salaün, Günther Noack
Cc: Jonathan Corbet, Shuah Khan, Sebastian Andrzej Siewior,
linux-security-module, linux-doc, linux-kernel, Doehyun Baek
The Landlock audit code can emit fs.resolve_unix as a filesystem blocker
for pathname UNIX socket resolution denials, but the admin guide's blockers
list did not mention it.
Add the missing blocker name and ABI version to keep the audit
documentation in sync with the emitted records.
Fixes: ae97330d1bd6 ("landlock: Control pathname UNIX domain socket resolution by path")
Signed-off-by: Doehyun Baek <doehyunbaek@gmail.com>
---
Documentation/admin-guide/LSM/landlock.rst | 1 +
1 file changed, 1 insertion(+)
diff --git a/Documentation/admin-guide/LSM/landlock.rst b/Documentation/admin-guide/LSM/landlock.rst
index 314052bbeb0a..8eb85c9381ff 100644
--- a/Documentation/admin-guide/LSM/landlock.rst
+++ b/Documentation/admin-guide/LSM/landlock.rst
@@ -52,6 +52,7 @@ AUDIT_LANDLOCK_ACCESS
- fs.refer (ABI 2+)
- fs.truncate (ABI 3+)
- fs.ioctl_dev (ABI 5+)
+ - fs.resolve_unix (ABI 9+)
**net.*** - Network access rights (ABI 4+):
- net.bind_tcp - TCP port binding was denied
base-commit: ab9de95c9cf952332ab79453b4b5d1bfca8e514f
--
2.43.0
^ permalink raw reply related
* Re: [PATCH v8 43/46] KVM: selftests: Check fd/flags provided to mmap() when setting up memslot
From: Fuad Tabba @ 2026-06-25 9:20 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-43-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:32, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Sean Christopherson <seanjc@google.com>
>
> Check that a valid fd provided to mmap() must be accompanied by MAP_SHARED.
>
> With an invalid fd (usually used for anonymous mappings), there are no
> constraints on mmap() flags.
>
> Add this check to make sure that when a guest_memfd is used as region->fd,
> the flag provided to mmap() will include MAP_SHARED.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> [Rephrase assertion message.]
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Cheers,
/fuad
> ---
> tools/testing/selftests/kvm/lib/kvm_util.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> index 0b2256ea65ff9..6b304e8a0e0d5 100644
> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> @@ -1110,6 +1110,9 @@ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
> src_type == VM_MEM_SRC_SHARED_HUGETLB);
> }
>
> + TEST_ASSERT(region->fd == -1 || backing_src_is_shared(src_type),
> + "A valid fd provided to mmap() must be accompanied by MAP_SHARED.");
> +
> region->mmap_start = __kvm_mmap(region->mmap_size, PROT_READ | PROT_WRITE,
> vm_mem_backing_src_alias(src_type)->flag,
> region->fd, mmap_offset);
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH v8 42/46] KVM: selftests: Provide common function to set memory attributes
From: Fuad Tabba @ 2026-06-25 9:09 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-42-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:32, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Sean Christopherson <seanjc@google.com>
>
> Introduce vm_mem_set_memory_attributes(), which handles setting of memory
> attributes for a range of guest physical addresses, regardless of whether
> the attributes should be set via guest_memfd or via the memory attributes
> at the VM level.
>
> Refactor existing vm_mem_set_{shared,private} functions to use the new
> function. Opportunistically update the size parameter to use size_t instead
> of u64.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> Co-developed-by: Ackerley Tng <ackerleytng@google.com>
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Cheers,
/fuad
> ---
> tools/testing/selftests/kvm/include/kvm_util.h | 46 +++++++++++++++++++-------
> 1 file changed, 34 insertions(+), 12 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
> index 3a6b1fa7f26ef..db1442da21bb1 100644
> --- a/tools/testing/selftests/kvm/include/kvm_util.h
> +++ b/tools/testing/selftests/kvm/include/kvm_util.h
> @@ -454,18 +454,6 @@ static inline void vm_set_memory_attributes(struct kvm_vm *vm, gpa_t gpa,
> vm_ioctl(vm, KVM_SET_MEMORY_ATTRIBUTES, &attr);
> }
>
> -static inline void vm_mem_set_private(struct kvm_vm *vm, gpa_t gpa,
> - u64 size)
> -{
> - vm_set_memory_attributes(vm, gpa, size, KVM_MEMORY_ATTRIBUTE_PRIVATE);
> -}
> -
> -static inline void vm_mem_set_shared(struct kvm_vm *vm, gpa_t gpa,
> - u64 size)
> -{
> - vm_set_memory_attributes(vm, gpa, size, 0);
> -}
> -
> static inline int __gmem_set_memory_attributes(int fd, u64 offset,
> size_t size, u64 attributes,
> u64 *error_offset)
> @@ -532,6 +520,40 @@ static inline void gmem_set_shared(int fd, u64 offset, size_t size)
> gmem_set_memory_attributes(fd, offset, size, 0);
> }
>
> +static inline void vm_mem_set_memory_attributes(struct kvm_vm *vm, gpa_t gpa,
> + size_t size, u64 attrs)
> +{
> + if (kvm_has_gmem_attributes) {
> + gpa_t end = gpa + size;
> + off_t fd_offset;
> + gpa_t addr;
> + size_t len;
> + int fd;
> +
> + for (addr = gpa; addr < end; addr += len) {
> + fd = kvm_gpa_to_guest_memfd(vm, addr, &fd_offset, &len);
> + len = min(end - addr, len);
> +
> + gmem_set_memory_attributes(fd, fd_offset, len, attrs);
> + }
> + } else {
> + vm_set_memory_attributes(vm, gpa, size, attrs);
> + }
> +}
> +
> +static inline void vm_mem_set_private(struct kvm_vm *vm, gpa_t gpa,
> + size_t size)
> +{
> + vm_mem_set_memory_attributes(vm, gpa, size,
> + KVM_MEMORY_ATTRIBUTE_PRIVATE);
> +}
> +
> +static inline void vm_mem_set_shared(struct kvm_vm *vm, gpa_t gpa,
> + size_t size)
> +{
> + vm_mem_set_memory_attributes(vm, gpa, size, 0);
> +}
> +
> void vm_guest_mem_fallocate(struct kvm_vm *vm, gpa_t gpa, u64 size,
> bool punch_hole);
>
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH v8 41/46] KVM: selftests: Provide function to look up guest_memfd details from gpa
From: Fuad Tabba @ 2026-06-25 8:58 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-41-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:32, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Ackerley Tng <ackerleytng@google.com>
>
> Introduce a new helper, kvm_gpa_to_guest_memfd(), to find the
> guest_memfd-related details of a memory region that contains a given guest
> physical address (GPA).
>
> The function returns the file descriptor for the memfd, the offset into
> the file that corresponds to the GPA, and the number of bytes remaining
> in the region from that GPA.
>
> kvm_gpa_to_guest_memfd() was factored out from vm_guest_mem_fallocate();
> refactor vm_guest_mem_fallocate() to use the new helper.
>
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
> Co-developed-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Cheers,
/fuad
> ---
> tools/testing/selftests/kvm/include/kvm_util.h | 3 +++
> tools/testing/selftests/kvm/lib/kvm_util.c | 37 ++++++++++++++++----------
> 2 files changed, 26 insertions(+), 14 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
> index 79ab64ac8b869..3a6b1fa7f26ef 100644
> --- a/tools/testing/selftests/kvm/include/kvm_util.h
> +++ b/tools/testing/selftests/kvm/include/kvm_util.h
> @@ -428,6 +428,9 @@ static inline void vm_enable_cap(struct kvm_vm *vm, u32 cap, u64 arg0)
> vm_ioctl(vm, KVM_ENABLE_CAP, &enable_cap);
> }
>
> +int kvm_gpa_to_guest_memfd(struct kvm_vm *vm, gpa_t gpa, off_t *fd_offset,
> + size_t *nr_bytes);
> +
> /*
> * KVM_SET_MEMORY_ATTRIBUTES{,2} overwrites _all_ attributes. These
> * flows need significant enhancements to support multiple attributes.
> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> index 524ef97d634bf..0b2256ea65ff9 100644
> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> @@ -1305,27 +1305,20 @@ void vm_guest_mem_fallocate(struct kvm_vm *vm, u64 base, u64 size,
> bool punch_hole)
> {
> const int mode = FALLOC_FL_KEEP_SIZE | (punch_hole ? FALLOC_FL_PUNCH_HOLE : 0);
> - struct userspace_mem_region *region;
> u64 end = base + size;
> - gpa_t gpa, len;
> off_t fd_offset;
> - int ret;
> + int fd, ret;
> + size_t len;
> + gpa_t gpa;
>
> for (gpa = base; gpa < end; gpa += len) {
> - u64 offset;
> -
> - region = userspace_mem_region_find(vm, gpa, gpa);
> - TEST_ASSERT(region && region->region.flags & KVM_MEM_GUEST_MEMFD,
> - "Private memory region not found for GPA 0x%lx", gpa);
> + fd = kvm_gpa_to_guest_memfd(vm, gpa, &fd_offset, &len);
> + len = min(end - gpa, len);
>
> - offset = gpa - region->region.guest_phys_addr;
> - fd_offset = region->region.guest_memfd_offset + offset;
> - len = min_t(u64, end - gpa, region->region.memory_size - offset);
> -
> - ret = fallocate(region->region.guest_memfd, mode, fd_offset, len);
> + ret = fallocate(fd, mode, fd_offset, len);
> TEST_ASSERT(!ret, "fallocate() failed to %s at %lx (len = %lu), fd = %d, mode = %x, offset = %lx",
> punch_hole ? "punch hole" : "allocate", gpa, len,
> - region->region.guest_memfd, mode, fd_offset);
> + fd, mode, fd_offset);
> }
> }
>
> @@ -1662,6 +1655,22 @@ void *addr_gpa2alias(struct kvm_vm *vm, gpa_t gpa)
> return (void *) ((uintptr_t) region->host_alias + offset);
> }
>
> +int kvm_gpa_to_guest_memfd(struct kvm_vm *vm, gpa_t gpa, off_t *fd_offset,
> + size_t *nr_bytes)
> +{
> + struct userspace_mem_region *region;
> + gpa_t gpa_offset;
> +
> + region = userspace_mem_region_find(vm, gpa, gpa);
> + TEST_ASSERT(region && region->region.flags & KVM_MEM_GUEST_MEMFD,
> + "guest_memfd memory region not found for GPA 0x%lx", gpa);
> +
> + gpa_offset = gpa - region->region.guest_phys_addr;
> + *fd_offset = region->region.guest_memfd_offset + gpa_offset;
> + *nr_bytes = region->region.memory_size - gpa_offset;
> + return region->region.guest_memfd;
> +}
> +
> /* Create an interrupt controller chip for the specified VM. */
> void vm_create_irqchip(struct kvm_vm *vm)
> {
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH 1/2] cgroup/dmem: add per-region event counters
From: Natalie Vock @ 2026-06-25 8:57 UTC (permalink / raw)
To: Hongfu Li, tj
Cc: cgroups, corbet, dev, dri-devel, hannes, linux-doc, linux-kernel,
mkoutny, mripard, skhan, hongfu.li
In-Reply-To: <20260625021053.488107-1-lihongfu@kylinos.cn>
Hi,
On 6/25/26 04:10, Hongfu Li wrote:
> Hi, Tejun
> Thanks for the review comments.
>
>>> Add dmem.events to report hierarchical low/max event counts per DMEM
>>> region. Increment counters on dmem.max allocation failures and
>>> dmem.low protection events. The file is available for non-root cgroups
>>> only.
>>
>> Please don't double space in descs or comments. Also, maybe it's obvious but
>> it'd help if you list why and how this is useful. Why do we want to add
>> this?
>
> I'll fix the double spacing in the commit message and comments.
>
> As for the motivation: dmem already exposes per-region limits and current
> usage, but not how often those limits actually matter at runtime. Without
> event counters, it's hard to tell whether allocation failures come from
> this cgroup, a parent limit, or pressure elsewhere in the hierarchy.
> dmem.events provides that visibility for tuning dmem.low/dmem.max and
> diagnosing recurring device memory pressure.
Shouldn't you be able to deduce this rather trivially from just looking
at the current usage together with the low/max limits you already set?
I'm not sure I really see anything this events file provides that
analysis of current usage and set limits doesn't? If your usage is
highly variable, the separately-developed dmem.peak file might also suit
your needs, but still, not sure what you can do with dmem.events that
you can't already do with these tools.
Best,
Natalie
>
> I'll expand the commit message to cover this.
>
>>> + dmem.events
>>> + A read-only file that reports the number of times each cgroup
>>> + has hit its configured memory limits. The format lists each
>>> + region on a single line, followed by the event counters::
>>> +
>>> + drm/0000:03:00.0/vram0 low 0 max 3
>>> + drm/0000:03:00.0/stolen low 0 max 0
>>
>> This isn't a supported file format. Please read the documentation on allowed
>> formats.
>
> Thanks for catching this. I'll switch dmem.events to nested-keyed format (region low=N max=M).
>
> Thanks again for the valuable feedback.
>
> Best regards,
> Hongfu
^ permalink raw reply
* Re: [PATCH v8 40/46] KVM: selftests: Reset shared memory after hole-punching
From: Fuad Tabba @ 2026-06-25 8:46 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-40-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:32, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Ackerley Tng <ackerleytng@google.com>
>
> private_mem_conversions_test used to reset the shared memory that was used
> for the test to an initial pattern at the end of each test iteration. Then,
> it would punch out the pages, which would zero memory.
>
> Without in-place conversion, the resetting would write shared memory, and
> hole-punching will zero private memory, hence resetting the test to the
> state at the beginning of the for loop.
>
> With in-place conversion, resetting writes memory as shared, and
> hole-punching zeroes the same physical memory, hence undoing the reset
> done before the hole punch.
>
> Move the resetting after the hole-punching, and reset the entire
> PER_CPU_DATA_SIZE instead of just the tested range.
>
> With in-place conversion, this zeroes and then resets the same physical
> memory. Without in-place conversion, the private memory is zeroed, and the
> shared memory is reset to init_p.
>
> This is sufficient since at each test stage, the memory is assumed to start
> as shared, and private memory is always assumed to start zeroed. Conversion
> zeroes memory, so the future test stages will work as expected.
>
> Fixes: 43f623f350ce1 ("KVM: selftests: Add x86-only selftest for private memory conversions")
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Cheers,
/fuad
> ---
> tools/testing/selftests/kvm/x86/private_mem_conversions_test.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c b/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
> index 861baff201e78..289ad10063fca 100644
> --- a/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
> +++ b/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
> @@ -202,15 +202,18 @@ static void guest_test_explicit_conversion(u64 base_gpa, bool do_fallocate)
> guest_sync_shared(gpa, size, p3, p4);
> memcmp_g(gpa, p4, size);
>
> - /* Reset the shared memory back to the initial pattern. */
> - memset((void *)gpa, init_p, size);
> -
> /*
> * Free (via PUNCH_HOLE) *all* private memory so that the next
> * iteration starts from a clean slate, e.g. with respect to
> * whether or not there are pages/folios in guest_mem.
> */
> guest_map_shared(base_gpa, PER_CPU_DATA_SIZE, true);
> +
> + /*
> + * Hole-punching above zeroed private memory. Reset shared
> + * memory in preparation for the next GUEST_STAGE.
> + */
> + memset((void *)base_gpa, init_p, PER_CPU_DATA_SIZE);
> }
> }
>
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [RFC v2 PATCH] reserve_mem: add support for static memory
From: Mike Rapoport @ 2026-06-25 8:37 UTC (permalink / raw)
To: Shyam Saini
Cc: linux-mm, linux-doc, linux-kernel, akpm, tgopinath, bboscaccy,
kees, tony.luck, gpiccoli, bp, rdunlap, peterz, feng.tang,
dapeng1.mi, elver, enelsonmoore, kuba, lirongqing, ebiggers,
Catalin Marinas, Will Deacon, Ard Biesheuvel, David Hildenbrand,
linux-arm-kernel
In-Reply-To: <ajyC2eX9MKSU84Z8@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net>
Hi Shyam,
On Wed, Jun 24, 2026 at 06:22:33PM -0700, Shyam Saini wrote:
> On 21 Jun 2026 13:36, Mike Rapoport wrote:
> > On Thu, Jun 18, 2026 at 11:23:31PM -0700, Shyam Saini wrote:
> > > reserve_mem relies on dynamic memory allocation, this limits the
> > > usecase where memory is required to be preserved across the boots.
> > > Eg: ramoops memory reservation on ACPI platforms
> > >
> > > So add support to pass a pre-determined static address and reserve
> > > memory at a specified location. This enables use case like ramoops
> > > on ACPI platforms to reliably access ramoops region with previous
> > > boot logs.
> > >
> > > Also skip the parsing of <align> when static address is passed.
> > >
> > > Example syntax for static address
> > > reserve_mem=4M@0x1E0000000:oops
> >
> > reserve_mem is best effort by design because such hacks as well as memmap=
> > cannot guarantee this memory is actually free.
> >
> > If you want to preserve ramoops reliably, use KHO with reserve_mem.
> > The first kernel will allocate memory, this memory will be preserved by KHO
> > and could be picked up by the second kernel.
>
> ok, On ARM64 DTS systems, we can reserve ramoops memory in the device tree during
> the warm reboot.
The cc list actually implied x86 ;-)
Added arm64 folks now.
> For an equivalent ARM64 ACPI platform, what is the recommended way to reserve
> and preserve that memory across the boots?
I don't think it exists, but a command line option (be it memmap= or
reserve_mem=) does not seem the right way to me.
Most of the arguments that were made against adding memmap= to arm64 [1]
apply here.
If kexec is an option, KHO provides a reliable way to preserve memory
across boots.
If kexec is not an option, we should look for a generic way to specify
something like DT's reserved_mem for ACPI/EFI systems.
[1] https://lkml.kernel.org/lkml/20201118063314.22940-1-song.bao.hua@hisilicon.com/T/
> Thanks,
> Shyam
--
Sincerely yours,
Mike.
^ permalink raw reply
* Re: [PATCH] power: supply: bd71828: add a terminating table border
From: Matti Vaittinen @ 2026-06-25 8:07 UTC (permalink / raw)
To: Randy Dunlap, linux-doc; +Cc: Andreas Kemnade, Sebastian Reichel, linux-pm
In-Reply-To: <20260620011821.3568674-1-rdunlap@infradead.org>
On 20/06/2026 04:18, Randy Dunlap wrote:
> Fix a documentation build error by adding a bottom table border:
>
> Documentation/ABI/testing/sysfs-class-power-bd71828:1: ERROR: Malformed table.
> No bottom table border found.
> ============ ===========================================
> 1 automatic adjustment of input current limit
> 0 no adjustment of input current limit. This
> helps for more unusual power sources like
> solar modules. [docutils]
>
> Fixes: e92786dd86a2 ("power: supply: bd71828: sysfs for auto input current limitation")
> Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
> ---
> Cc: Andreas Kemnade <andreas@kemnade.info>
> Cc: Matti Vaittinen <mazziesaccount@gmail.com>
> Cc: Sebastian Reichel <sebastian.reichel@collabora.com>
> Cc: linux-pm@vger.kernel.org
>
> Documentation/ABI/testing/sysfs-class-power-bd71828 | 1 +
> 1 file changed, 1 insertion(+)
>
> --- linux-next-20260619.orig/Documentation/ABI/testing/sysfs-class-power-bd71828
> +++ linux-next-20260619/Documentation/ABI/testing/sysfs-class-power-bd71828
> @@ -10,3 +10,4 @@ Description:
> 0 no adjustment of input current limit. This
> helps for more unusual power sources like
> solar modules.
> + ============ ===========================================
Acked-by: Matti Vaittinen <mazziesaccount@gmail.com>
--
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland
~~ When things go utterly wrong vim users can always type :help! ~~
^ permalink raw reply
* Re: [PATCH v8 39/46] KVM: selftests: Test conversion with elevated page refcount
From: Fuad Tabba @ 2026-06-25 8:04 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-39-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:32, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Ackerley Tng <ackerleytng@google.com>
>
> Add a selftest to verify that converting a shared guest_memfd page to a
> private page fails if the page has an elevated reference count.
>
> When KVM converts a shared page to a private one, it expects the page to
> have a reference count equal to the reference counts taken by the
> filemap. If another kernel subsystem holds a reference to the page, the
> conversion must be aborted.
>
> The test asserts that both bulk and single-page conversion attempts
> correctly fail with EAGAIN for the pinned page. After the page is unpinned,
> the test verifies that subsequent conversions succeed.
>
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
> Co-developed-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
Not sure Sashiko's concern is worth it.
Reviewed-by: Fuad Tabba <tabba@google.com>
Cheers,
/fuad
> ---
> .../kvm/x86/guest_memfd_conversions_test.c | 56 ++++++++++++++++++++++
> 1 file changed, 56 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c b/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
> index 99b0023609670..4ebbd29029526 100644
> --- a/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
> +++ b/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
> @@ -441,6 +441,62 @@ GMEM_CONVERSION_TEST_INIT_SHARED(forked_accesses)
> #undef TEST_STATE_AWAIT
> }
>
> +static void test_convert_to_private_fails(test_data_t *t, u64 pgoff,
> + size_t nr_pages,
> + u64 expected_error_offset)
> +{
> + /* +1 to make it anything but expected_error_offset. */
> + u64 error_offset = expected_error_offset + 1;
> + u64 offset = pgoff * page_size;
> + int ret;
> +
> + do {
> + ret = __gmem_set_private(t->gmem_fd, offset,
> + nr_pages * page_size, &error_offset);
> + } while (ret == -1 && errno == EINTR);
> + TEST_ASSERT(ret == -1 && errno == EAGAIN,
> + "Wanted EAGAIN on page %lu, got %d (ret = %d)", pgoff,
> + errno, ret);
> + TEST_ASSERT_EQ(error_offset, expected_error_offset);
> +}
> +
> +GMEM_CONVERSION_MULTIPAGE_TEST_INIT_SHARED(elevated_refcount, 4)
> +{
> + int i;
> +
> + pin_pages(t->mem + test_page * page_size, page_size);
> +
> + for (i = 0; i < nr_pages; i++)
> + test_shared(t, i, 0, 'A', 'B');
> +
> + /*
> + * Converting in bulk should fail as long any page in the range has
> + * unexpected refcounts.
> + */
> + test_convert_to_private_fails(t, 0, nr_pages, test_page * page_size);
> +
> + for (i = 0; i < nr_pages; i++) {
> + /*
> + * Converting page-wise should also fail as long any page in the
> + * range has unexpected refcounts.
> + */
> + if (i == test_page)
> + test_convert_to_private_fails(t, i, 1, test_page * page_size);
> + else
> + test_convert_to_private(t, i, 'B', 'C');
> + }
> +
> + unpin_pages();
> +
> + gmem_set_private(t->gmem_fd, 0, nr_pages * page_size);
> +
> + for (i = 0; i < nr_pages; i++) {
> + char expected = i == test_page ? 'B' : 'C';
> +
> + test_private(t, i, expected, 'D');
> + }
> +}
> +
> int main(int argc, char *argv[])
> {
> TEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_SW_PROTECTED_VM));
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH v8 38/46] KVM: selftests: Add helpers to pin pages with CONFIG_GUP_TEST
From: Fuad Tabba @ 2026-06-25 7:40 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-38-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:32, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Ackerley Tng <ackerleytng@google.com>
>
> Add helper functions to allow KVM selftests to pin memory using
> CONFIG_GUP_TEST. This is useful for testing scenarios where some page has
> an increased refcount. such as in guest_memfd in-place conversion tests.
>
> The helpers open /sys/kernel/debug/gup_test and invoke the
> PIN_LONGTERM_TEST_START and PIN_LONGTERM_TEST_STOP ioctls. Since this
> functionality depends on the kernel being built with CONFIG_GUP_TEST,
> provide stub implementations that trigger a test failure if the
> configuration is missing.
>
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
nit below, otherwise:
Reviewed-by: Fuad Tabba <tabba@google.com>
Cheers,
/fuad
> ---
> tools/testing/selftests/kvm/include/kvm_util.h | 3 +++
> tools/testing/selftests/kvm/lib/kvm_util.c | 23 +++++++++++++++++++++++
> 2 files changed, 26 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
> index 323d06b5699ec..79ab64ac8b869 100644
> --- a/tools/testing/selftests/kvm/include/kvm_util.h
> +++ b/tools/testing/selftests/kvm/include/kvm_util.h
> @@ -1195,6 +1195,9 @@ static inline int pin_self_to_any_cpu(void)
> return pin_task_to_any_cpu(pthread_self());
> }
>
> +void pin_pages(void *vaddr, uint64_t size);
> +void unpin_pages(void);
> +
> void kvm_print_vcpu_pinning_help(void);
> void kvm_parse_vcpu_pinning(const char *pcpus_string, u32 vcpu_to_pcpu[],
> int nr_vcpus);
> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> index b73817f7bc803..524ef97d634bf 100644
> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> @@ -18,6 +18,8 @@
> #include <unistd.h>
> #include <linux/kernel.h>
>
> +#include "../../../../mm/gup_test.h"
> +
> #define KVM_UTIL_MIN_PFN 2
>
> u32 guest_random_seed;
> @@ -639,6 +641,27 @@ int __pin_task_to_cpu(pthread_t task, int cpu)
> return pthread_setaffinity_np(task, sizeof(cpuset), &cpuset);
> }
>
> +static int gup_test_fd = -1;
> +
> +void pin_pages(void *vaddr, uint64_t size)
> +{
> + const struct pin_longterm_test args = {
> + .addr = (uint64_t)vaddr,
> + .size = size,
> + .flags = PIN_LONGTERM_TEST_FLAG_USE_WRITE,
> + };
> +
> + gup_test_fd = __open_path_or_exit("/sys/kernel/debug/gup_test", O_RDWR,
> + "Is CONFIG_GUP_TEST enabled?");
nit: should you close this/reset it to -1 after the tests?
> +
> + TEST_ASSERT_EQ(ioctl(gup_test_fd, PIN_LONGTERM_TEST_START, &args), 0);
> +}
> +
> +void unpin_pages(void)
> +{
> + TEST_ASSERT_EQ(ioctl(gup_test_fd, PIN_LONGTERM_TEST_STOP), 0);
> +}
> +
> static u32 parse_pcpu(const char *cpu_str, const cpu_set_t *allowed_mask)
> {
> u32 pcpu = atoi_non_negative("CPU number", cpu_str);
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH v16 04/14] lib: kstrtox: add initial value to _parse_integer_limit()
From: Rodrigo Alencar @ 2026-06-25 7:30 UTC (permalink / raw)
To: Jonathan Cameron, Rodrigo Alencar
Cc: rodrigo.alencar, linux-kernel, linux-iio, devicetree, linux-doc,
linux, David Lechner, Andy Shevchenko, Lars-Peter Clausen,
Michael Hennerich, Rob Herring, Krzysztof Kozlowski, Conor Dooley,
Jonathan Corbet, Andrew Morton, Petr Mladek, Steven Rostedt,
Andy Shevchenko, Rasmus Villemoes, Sergey Senozhatsky, Shuah Khan
In-Reply-To: <20260624155414.61755e9a@jic23-huawei>
On 24/06/26 15:54, Jonathan Cameron wrote:
> On Sun, 14 Jun 2026 21:00:44 +0100
> Jonathan Cameron <jic23@kernel.org> wrote:
>
> > On Thu, 4 Jun 2026 11:09:33 +0100
> > Rodrigo Alencar <455.rodrigo.alencar@gmail.com> wrote:
> >
> > > On 26/06/04 10:58AM, Rodrigo Alencar via B4 Relay wrote:
> > > > From: Rodrigo Alencar <rodrigo.alencar@analog.com>
> > > >
> > > > Add init parameter to _parse_integer_limit() that defines an initial
> > > > value for the accumulated result when parsing an 64-bit integer. The
> > > > new function prototype is adjusted so that the _parse_integer() macros
> > > > stay consistent allowing for one more argument, which defaults to 0.
> > >
> > > ...
> > >
> > > > noinline
> > > > unsigned int _parse_integer_limit(const char *s, unsigned int base, unsigned long long *p,
> > > > - size_t max_chars)
> > > > + size_t max_chars, unsigned long long init)
> > > > {
> > > > unsigned long long res;
> > > > unsigned int rv;
> > > >
> > > > - res = 0;
> > > > + res = init;
> > >
> > > This might generate conflict, as the code around have changed in linux-next.
> > > It is an easy fix though.
> > >
> > Thanks for the heads up. Hopefully that will all fall out when I rebase testing
> > on rc1 once that is out.
> I've done a mid merge cycle rebase as the char-misc branches have merged.
> So this should be resolve on my testing branch now.
https://lore.kernel.org/oe-kbuild-all/202606250230.etPGuolf-lkp@intel.com/
Apparently, the documentation header now includes parameter descriptions.
The new one is missing.
--
Kind regards,
Rodrigo Alencar
^ permalink raw reply
* Re: [PATCH 1/7] dt-bindings: adm1275: ROHM BD12780 hot-swap controller
From: Krzysztof Kozlowski @ 2026-06-25 7:21 UTC (permalink / raw)
To: Matti Vaittinen
Cc: Matti Vaittinen, Matti Vaittinen, Guenter Roeck, Rob Herring,
Krzysztof Kozlowski, Conor Dooley, Jonathan Corbet, Shuah Khan,
Wensheng Wang, Ashish Yadav, Kim Seer Paller, Cedric Encarnacion,
Chris Packham, Yuxi Wang, Charles Hsu, ChiShih Tsai, linux-hwmon,
devicetree, linux-kernel, linux-doc
In-Reply-To: <bd9419aa-1a21-4ca2-990b-ad1bebf5c9c8@gmail.com>
On 25/06/2026 09:05, Matti Vaittinen wrote:
>>> + - adi,adm1075
>>> + - adi,adm1272
>>> + - adi,adm1273
>>> + - adi,adm1275
>>> + - adi,adm1276
>>> + - adi,adm1278
>>> + - adi,adm1281
>>> + - adi,adm1293
>>> + - adi,adm1294
>>> + - rohm,bd12780
>>> + - silergy,mc09c
>>> +
>>> +# Require BD12780 as a fall-back for BD12780A.
>>
>> No need for the comment, schema is quite explicit.
>
> Eh... I know it is explicit for one who fluently reads yaml. Not all of
> us do that :| (See my reply to the previous comment...) I am not sure
> the comment hurts - while I am sure it helps occasional binding reader
> like me. Can you please reconsider keeping the comment?
This one does not, but if people take the existing code as a starting
point or even as an example in arguments ("he did like that, so I am
allowed as well"), it gets multiplied and we have more bindings with
redundant data.
That's said, if you insist then fine with me, keep it.
Best regards,
Krzysztof
^ permalink raw reply
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