Re: [PATCH] kernel: trace: preemptirq_delay_test: add MODULE_DESCRIPTION()

[Google]

On Sat, 18 May 2024 15:54:49 -0700
Jeff Johnson  wrote:

> Fix the 'make W=1' warning:
> 
> WARNING: modpost: missing MODULE_DESCRIPTION() in 
> kernel/trace/preemptirq_delay_test.o
> 

Looks good to me.

Acked-by: Masami Hiramatsu (Google) 

Fixes: f96e8577da10 ("lib: Add module for testing preemptoff/irqsoff latency 
tracers")

Thanks,

> Signed-off-by: Jeff Johnson 
> ---
>  kernel/trace/preemptirq_delay_test.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/kernel/trace/preemptirq_delay_test.c 
> b/kernel/trace/preemptirq_delay_test.c
> index 8c4ffd076162..cb0871fbdb07 100644
> --- a/kernel/trace/preemptirq_delay_test.c
> +++ b/kernel/trace/preemptirq_delay_test.c
> @@ -215,4 +215,5 @@ static void __exit preemptirq_delay_exit(void)
>  
>  module_init(preemptirq_delay_init)
>  module_exit(preemptirq_delay_exit)
> +MODULE_DESCRIPTION("Preempt / IRQ disable delay thread to test latency 
> tracers");
>  MODULE_LICENSE("GPL v2");
> 
> ---
> base-commit: 674143feb6a8c02d899e64e2ba0f992896afd532
> change-id: 20240518-md-preemptirq_delay_test-552cd20e7b0b
> 


-- 
Masami Hiramatsu (Google) 

[PATCH] kernel: trace: preemptirq_delay_test: add MODULE_DESCRIPTION()

[Jeff Johnson]

Fix the 'make W=1' warning:

WARNING: modpost: missing MODULE_DESCRIPTION() in 
kernel/trace/preemptirq_delay_test.o

Signed-off-by: Jeff Johnson 
---
 kernel/trace/preemptirq_delay_test.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/trace/preemptirq_delay_test.c 
b/kernel/trace/preemptirq_delay_test.c
index 8c4ffd076162..cb0871fbdb07 100644
--- a/kernel/trace/preemptirq_delay_test.c
+++ b/kernel/trace/preemptirq_delay_test.c
@@ -215,4 +215,5 @@ static void __exit preemptirq_delay_exit(void)
 
 module_init(preemptirq_delay_init)
 module_exit(preemptirq_delay_exit)
+MODULE_DESCRIPTION("Preempt / IRQ disable delay thread to test latency 
tracers");
 MODULE_LICENSE("GPL v2");

---
base-commit: 674143feb6a8c02d899e64e2ba0f992896afd532
change-id: 20240518-md-preemptirq_delay_test-552cd20e7b0b

Re: [PATCH v3 2/2] remoteproc: k3-r5: Do not allow core1 to power up before core0 via sysfs

[Christophe JAILLET]

Le 30/04/2024 à 12:53, Beleswar Padhi a écrit :

PSC controller has a limitation that it can only power-up the second
core when the first core is in ON state. Power-state for core0 should be
equal to or higher than core1.

Therefore, prevent core1 from powering up before core0 during the start
process from sysfs. Similarly, prevent core0 from shutting down before
core1 has been shut down from sysfs.

Fixes: 6dedbd1d5443 ("remoteproc: k3-r5: Add a remoteproc driver for R5F 
subsystem")

Signed-off-by: Beleswar Padhi 
---
  drivers/remoteproc/ti_k3_r5_remoteproc.c | 23 +--
  1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c 
b/drivers/remoteproc/ti_k3_r5_remoteproc.c
index 6d6afd6beb3a..1799b4f6d11e 100644
--- a/drivers/remoteproc/ti_k3_r5_remoteproc.c
+++ b/drivers/remoteproc/ti_k3_r5_remoteproc.c
@@ -548,7 +548,7 @@ static int k3_r5_rproc_start(struct rproc *rproc)
struct k3_r5_rproc *kproc = rproc->priv;
struct k3_r5_cluster *cluster = kproc->cluster;
struct device *dev = kproc->dev;
-   struct k3_r5_core *core;
+   struct k3_r5_core *core0, *core;
u32 boot_addr;
int ret;
  
@@ -574,6 +574,15 @@ static int k3_r5_rproc_start(struct rproc *rproc)

goto unroll_core_run;
}
} else {
+   /* do not allow core 1 to start before core 0 */
+   core0 = list_first_entry(&cluster->cores, struct k3_r5_core,
+elem);
+   if (core != core0 && core0->rproc->state == RPROC_OFFLINE) {
+   dev_err(dev, "%s: can not start core 1 before core 0\n",
+   __func__);
+   return -EPERM;
+   }
+
ret = k3_r5_core_run(core);
if (ret)
goto put_mbox;
@@ -619,7 +628,8 @@ static int k3_r5_rproc_stop(struct rproc *rproc)
  {
struct k3_r5_rproc *kproc = rproc->priv;
struct k3_r5_cluster *cluster = kproc->cluster;
-   struct k3_r5_core *core = kproc->core;
+   struct device *dev = kproc->dev;
+   struct k3_r5_core *core1, *core = kproc->core;
int ret;
  
  	/* halt all applicable cores */

@@ -632,6 +642,15 @@ static int k3_r5_rproc_stop(struct rproc *rproc)
}
}
} else {
+   /* do not allow core 0 to stop before core 1 */
+   core1 = list_last_entry(&cluster->cores, struct k3_r5_core,
+   elem);
+   if (core != core1 && core1->rproc->state != RPROC_OFFLINE) {
+   dev_err(dev, "%s: can not stop core 0 before core 1\n",
+   __func__);
+   return -EPERM;


Hi,

this patch has already reached -next, but should this "return -EPERM;" be :
ret = -EPERM;
goto put_mbox;

instead?

CJ


+   }
+
ret = k3_r5_core_halt(core);
if (ret)
goto out;

[PATCH v1 2/2] virt: pvmemcontrol: add Yuanchu and Pasha as maintainers

[Yuanchu Xie]

The pvmemcontrol driver lives under drivers/virt/pvmemcontrol. We
specify maintainers for the driver.

Signed-off-by: Yuanchu Xie 
---
 MAINTAINERS | 7 +++
 1 file changed, 7 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 3fdc3b09c171..fd77ce0c1328 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -18048,6 +18048,13 @@ L: linux-wirel...@vger.kernel.org
 S: Supported
 F: drivers/net/wireless/purelifi/plfxlc/
 
+PVMEMCONTROL GUEST DRIVER
+M: Yuanchu Xie 
+M: Pasha Tatashin 
+L: linux-kernel@vger.kernel.org
+S: Supported
+F: drivers/virt/pvmemcontrol/
+
 PVRUSB2 VIDEO4LINUX DRIVER
 M: Mike Isely 
 L: pvru...@isely.net   (subscribers-only)
-- 
2.45.0.rc1.225.g2a3ae87e7f-goog

[PATCH v1 1/2] virt: pvmemcontrol: control guest physical memory properties

[Yuanchu Xie]

Pvmemcontrol provides a way for the guest to control its physical memory
properties, and enables optimizations and security features. For
example, the guest can provide information to the host where parts of a
hugepage may be unbacked, or sensitive data may not be swapped out, etc.

Pvmemcontrol allows guests to manipulate its gPTE entries in the SLAT,
and also some other properties of the memory map the back's host memory.
This is achieved by using the KVM_CAP_SYNC_MMU capability. When this
capability is available, the changes in the backing of the memory region
on the host are automatically reflected into the guest. For example, an
mmap() or madvise() that affects the region will be made visible
immediately.

There are two components of the implementation: the guest Linux driver
and Virtual Machine Monitor (VMM) device. A guest-allocated shared
buffer is negotiated per-cpu through a few PCI MMIO registers, the VMM
device assigns a unique command for each per-cpu buffer. The guest
writes its pvmemcontrol request in the per-cpu buffer, then writes the
corresponding command into the command register, calling into the VMM
device to perform the pvmemcontrol request.

The synchronous per-cpu shared buffer approach avoids the kick and busy
waiting that the guest would have to do with virtio virtqueue transport.

User API
>From the userland, the pvmemcontrol guest driver is controlled via
ioctl(2) call. It requires CAP_SYS_ADMIN.

ioctl(fd, PVMEMCONTROL_IOCTL, struct pvmemcontrol_buf *buf);

Guest userland applications can tag VMAs and guest hugepages, or advise
the host on how to handle sensitive guest pages.

Supported function codes and their use cases:
PVMEMCONTROL_FREE/REMOVE/DONTNEED/PAGEOUT. For the guest. One can reduce
the struct page and page table lookup overhead by using hugepages backed
by smaller pages on the host. These pvmemcontrol commands can allow for
partial freeing of private guest hugepages to save memory. They also
allow kernel memory, such as kernel stacks and task_structs to be
paravirtualized if we expose kernel APIs.

PVMEMCONTROL_UNMERGEABLE is useful for security, when the VM does not
want to share its backing pages.
The same with PVMEMCONTROL_DONTDUMP, so sensitive pages are not included
in a dump.
MLOCK/UNLOCK can advise the host that sensitive information is not
swapped out on the host.

PVMEMCONTROL_MPROTECT_NONE/R/W/RW. For guest stacks backed by hugepages,
stack guard pages can be handled in the host and memory can be saved in
the hugepage.

PVMEMCONTROL_SET_VMA_ANON_NAME is useful for observability and debugging
how guest memory is being mapped on the host.

Sample program making use of PVMEMCONTROL_DONTNEED:
https://github.com/Dummyc0m/pvmemcontrol-user

The VMM implementation is being proposed for Cloud Hypervisor:
https://github.com/Dummyc0m/cloud-hypervisor/

Cloud Hypervisor issue:
https://github.com/cloud-hypervisor/cloud-hypervisor/issues/6318

-
Changelog
RFC v1 -> PATCH v1
- renamed memctl to pvmemcontrol
- defined device endianness as little endian

Signed-off-by: Yuanchu Xie 
---
 .../userspace-api/ioctl/ioctl-number.rst  |   2 +
 drivers/virt/Kconfig  |   2 +
 drivers/virt/Makefile |   1 +
 drivers/virt/pvmemcontrol/Kconfig |  10 +
 drivers/virt/pvmemcontrol/Makefile|   2 +
 drivers/virt/pvmemcontrol/pvmemcontrol.c  | 460 ++
 include/uapi/linux/pvmemcontrol.h |  75 +++
 7 files changed, 552 insertions(+)
 create mode 100644 drivers/virt/pvmemcontrol/Kconfig
 create mode 100644 drivers/virt/pvmemcontrol/Makefile
 create mode 100644 drivers/virt/pvmemcontrol/pvmemcontrol.c
 create mode 100644 include/uapi/linux/pvmemcontrol.h

diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst 
b/Documentation/userspace-api/ioctl/ioctl-number.rst
index c472423412bf..65bef09406d5 100644
--- a/Documentation/userspace-api/ioctl/ioctl-number.rst
+++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
@@ -370,6 +370,8 @@ Code  Seq#Include File  
 Comments
 0xCD  01 linux/reiserfs_fs.h
 0xCE  01-02  uapi/linux/cxl_mem.hCompute 
Express Link Memory Devices
 0xCF  02 fs/smb/client/cifs_ioctl.h
+0xDA  00 uapi/linux/pvmemcontrol.h   
Pvmemcontrol Device
+ 

 0xDB  00-0F  drivers/char/mwave/mwavepub.h
 0xDD  00-3F  ZFCP 
device driver see drivers/s390/scsi/
  

diff --git a/drivers/virt/Kconfig b/drivers/virt/Kconfig
index 40129b6f0eca..9e242216cde8 100644
--- a/drivers/virt/Kconfig
+++ b/drivers/virt/Kconfig
@@ -50,4 +50,6 @@ source "drivers/virt/acrn/Kconfig"
 
 source "drivers/virt/coco/Kconfig"
 
+source "drive