[regression]Boot Hang on Kernel 6.1.83+ with Dell PowerEdge R770 and Intel Xeon 6710E

[regression]Boot Hang on Kernel 6.1.83+ with Dell PowerEdge R770 and Intel Xeon 6710E

[Jinpu Wang]

Hello all,

We are experiencing a boot hang issue when booting kernel version
6.1.83+ on a Dell Inc. PowerEdge R770 equipped with an Intel Xeon
6710E processor. After extensive testing and use of `git bisect`, we
have traced the issue to commit:

`586e19c88a0c ("iommu/vt-d: Retrieve IOMMU perfmon capability information")`

This commit appears to be part of a larger patchset, which can be found here:
[Patchset on lore.kernel.org](https://lore.kernel.org/lkml/7c4b3e4e-1c5d-04f1-1891-84f686c94736@linux.intel.com/T/)

We attempted to boot with the `intel_iommu=off` option, but the system
hangs in the same manner. However, the system boots successfully after
disabling `CONFIG_INTEL_IOMMU_PERF_EVENTS`.

I'm reporting here in case others hit the same issue.

Any assistance or guidance on understanding/resolving this issue would
be greatly appreciated.

Thank you.
Jinpu Wang @ IONOS Cloud

Re: [regression]Boot Hang on Kernel 6.1.83+ with Dell PowerEdge R770 and Intel Xeon 6710E

[Greg KH]

On Thu, Oct 10, 2024 at 09:31:37AM +0200, Jinpu Wang wrote:
> Hello all,
> 
> We are experiencing a boot hang issue when booting kernel version
> 6.1.83+ on a Dell Inc. PowerEdge R770 equipped with an Intel Xeon
> 6710E processor. After extensive testing and use of `git bisect`, we
> have traced the issue to commit:
> 
> `586e19c88a0c ("iommu/vt-d: Retrieve IOMMU perfmon capability information")`
> 
> This commit appears to be part of a larger patchset, which can be found here:
> [Patchset on lore.kernel.org](https://lore.kernel.org/lkml/7c4b3e4e-1c5d-04f1-1891-84f686c94736@linux.intel.com/T/)
> 
> We attempted to boot with the `intel_iommu=off` option, but the system
> hangs in the same manner. However, the system boots successfully after
> disabling `CONFIG_INTEL_IOMMU_PERF_EVENTS`.

Is there any error messages?  Does the latest 6.6.y tree work properly?
If so, why not just use that, no new hardware should be using older
kernel trees anyway :)

thanks,

greg k-h

Re: [regression]Boot Hang on Kernel 6.1.83+ with Dell PowerEdge R770 and Intel Xeon 6710E

[Jinpu Wang]

Hi Greg,

On Thu, Oct 10, 2024 at 11:07 AM Greg KH <gregkh@linuxfoundation.org> wrote:
>
> On Thu, Oct 10, 2024 at 09:31:37AM +0200, Jinpu Wang wrote:
> > Hello all,
> >
> > We are experiencing a boot hang issue when booting kernel version
> > 6.1.83+ on a Dell Inc. PowerEdge R770 equipped with an Intel Xeon
> > 6710E processor. After extensive testing and use of `git bisect`, we
> > have traced the issue to commit:
> >
> > `586e19c88a0c ("iommu/vt-d: Retrieve IOMMU perfmon capability information")`
> >
> > This commit appears to be part of a larger patchset, which can be found here:
> > [Patchset on lore.kernel.org](https://lore.kernel.org/lkml/7c4b3e4e-1c5d-04f1-1891-84f686c94736@linux.intel.com/T/)
> >
> > We attempted to boot with the `intel_iommu=off` option, but the system
> > hangs in the same manner. However, the system boots successfully after
> > disabling `CONFIG_INTEL_IOMMU_PERF_EVENTS`.
>
> Is there any error messages?  Does the latest 6.6.y tree work properly?
> If so, why not just use that, no new hardware should be using older
> kernel trees anyway :)
No error, just hang, I've removed "quiet" and added "debug".
Yes, the latest 6.6.y tree works for this, but there are other
problems/dependency we have to solve.

>
> thanks,
Thanks!
>
> greg k-h

Re: [regression]Boot Hang on Kernel 6.1.83+ with Dell PowerEdge R770 and Intel Xeon 6710E

[Greg KH]

On Thu, Oct 10, 2024 at 11:13:42AM +0200, Jinpu Wang wrote:
> Hi Greg,
> 
> On Thu, Oct 10, 2024 at 11:07 AM Greg KH <gregkh@linuxfoundation.org> wrote:
> >
> > On Thu, Oct 10, 2024 at 09:31:37AM +0200, Jinpu Wang wrote:
> > > Hello all,
> > >
> > > We are experiencing a boot hang issue when booting kernel version
> > > 6.1.83+ on a Dell Inc. PowerEdge R770 equipped with an Intel Xeon
> > > 6710E processor. After extensive testing and use of `git bisect`, we
> > > have traced the issue to commit:
> > >
> > > `586e19c88a0c ("iommu/vt-d: Retrieve IOMMU perfmon capability information")`
> > >
> > > This commit appears to be part of a larger patchset, which can be found here:
> > > [Patchset on lore.kernel.org](https://lore.kernel.org/lkml/7c4b3e4e-1c5d-04f1-1891-84f686c94736@linux.intel.com/T/)
> > >
> > > We attempted to boot with the `intel_iommu=off` option, but the system
> > > hangs in the same manner. However, the system boots successfully after
> > > disabling `CONFIG_INTEL_IOMMU_PERF_EVENTS`.
> >
> > Is there any error messages?  Does the latest 6.6.y tree work properly?
> > If so, why not just use that, no new hardware should be using older
> > kernel trees anyway :)
> No error, just hang, I've removed "quiet" and added "debug".
> Yes, the latest 6.6.y tree works for this, but there are other
> problems/dependency we have to solve.

Ok, that implies that we need to add some other patch to 6.1.y, OR we
can revert it from 6.1.y.  Let me know what you think is the better
thing to do.

thanks,

greg k-h

Re: [regression]Boot Hang on Kernel 6.1.83+ with Dell PowerEdge R770 and Intel Xeon 6710E

[Jinpu Wang]

Hi Greg,


On Thu, Oct 10, 2024 at 11:31 AM Greg KH <gregkh@linuxfoundation.org> wrote:
>
> On Thu, Oct 10, 2024 at 11:13:42AM +0200, Jinpu Wang wrote:
> > Hi Greg,
> >
> > On Thu, Oct 10, 2024 at 11:07 AM Greg KH <gregkh@linuxfoundation.org> wrote:
> > >
> > > On Thu, Oct 10, 2024 at 09:31:37AM +0200, Jinpu Wang wrote:
> > > > Hello all,
> > > >
> > > > We are experiencing a boot hang issue when booting kernel version
> > > > 6.1.83+ on a Dell Inc. PowerEdge R770 equipped with an Intel Xeon
> > > > 6710E processor. After extensive testing and use of `git bisect`, we
> > > > have traced the issue to commit:
> > > >
> > > > `586e19c88a0c ("iommu/vt-d: Retrieve IOMMU perfmon capability information")`
> > > >
> > > > This commit appears to be part of a larger patchset, which can be found here:
> > > > [Patchset on lore.kernel.org](https://lore.kernel.org/lkml/7c4b3e4e-1c5d-04f1-1891-84f686c94736@linux.intel.com/T/)
> > > >
> > > > We attempted to boot with the `intel_iommu=off` option, but the system
> > > > hangs in the same manner. However, the system boots successfully after
> > > > disabling `CONFIG_INTEL_IOMMU_PERF_EVENTS`.
> > >
> > > Is there any error messages?  Does the latest 6.6.y tree work properly?
> > > If so, why not just use that, no new hardware should be using older
> > > kernel trees anyway :)
> > No error, just hang, I've removed "quiet" and added "debug".
> > Yes, the latest 6.6.y tree works for this, but there are other
> > problems/dependency we have to solve.
>
> Ok, that implies that we need to add some other patch to 6.1.y, OR we
> can revert it from 6.1.y.  Let me know what you think is the better
> thing to do.
>
I think better to revert both:
8c91a4bfc7f8 ("iommu: Fix compilation without CONFIG_IOMMU_INTEL")
586e19c88a0c ("iommu/vt-d: Retrieve IOMMU perfmon capability information")

unless other guys have a different opinon.
> thanks,
>
> greg k-h
Thanks!

Re: [regression]Boot Hang on Kernel 6.1.83+ with Dell PowerEdge R770 and Intel Xeon 6710E

[Liang, Kan]

On 2024-10-10 6:10 a.m., Jinpu Wang wrote:
> Hi Greg,
> 
> 
> On Thu, Oct 10, 2024 at 11:31 AM Greg KH <gregkh@linuxfoundation.org> wrote:
>>
>> On Thu, Oct 10, 2024 at 11:13:42AM +0200, Jinpu Wang wrote:
>>> Hi Greg,
>>>
>>> On Thu, Oct 10, 2024 at 11:07 AM Greg KH <gregkh@linuxfoundation.org> wrote:
>>>>
>>>> On Thu, Oct 10, 2024 at 09:31:37AM +0200, Jinpu Wang wrote:
>>>>> Hello all,
>>>>>
>>>>> We are experiencing a boot hang issue when booting kernel version
>>>>> 6.1.83+ on a Dell Inc. PowerEdge R770 equipped with an Intel Xeon
>>>>> 6710E processor. After extensive testing and use of `git bisect`, we
>>>>> have traced the issue to commit:
>>>>>
>>>>> `586e19c88a0c ("iommu/vt-d: Retrieve IOMMU perfmon capability information")`
>>>>>
>>>>> This commit appears to be part of a larger patchset, which can be found here:
>>>>> [Patchset on lore.kernel.org](https://lore.kernel.org/lkml/7c4b3e4e-1c5d-04f1-1891-84f686c94736@linux.intel.com/T/)
>>>>>
>>>>> We attempted to boot with the `intel_iommu=off` option, but the system
>>>>> hangs in the same manner. However, the system boots successfully after
>>>>> disabling `CONFIG_INTEL_IOMMU_PERF_EVENTS`.
>>>>
>>>> Is there any error messages?  Does the latest 6.6.y tree work properly?
>>>> If so, why not just use that, no new hardware should be using older
>>>> kernel trees anyway :)
>>> No error, just hang, I've removed "quiet" and added "debug".
>>> Yes, the latest 6.6.y tree works for this, but there are other
>>> problems/dependency we have to solve.
>>
>> Ok, that implies that we need to add some other patch to 6.1.y, OR we
>> can revert it from 6.1.y.  Let me know what you think is the better
>> thing to do.
>>
> I think better to revert both:
> 8c91a4bfc7f8 ("iommu: Fix compilation without CONFIG_IOMMU_INTEL")

I'm not sure about this one. May need baolu's comments.

> 586e19c88a0c ("iommu/vt-d: Retrieve IOMMU perfmon capability information")
>

7 patches are required to enable the IOMMU perfmon.
https://lore.kernel.org/all/20230128200428.1459118-1-kan.liang@linux.intel.com/
But it looks like only the above 1 patch is back ported to the 6.1.y.
Unless we can back port the rest of 6 patches, I think it should be ok
to revert it for 6.1.y.

Thanks,
Kan


> unless other guys have a different opinon.
>> thanks,
>>
>> greg k-h
> Thanks!

Re: [regression]Boot Hang on Kernel 6.1.83+ with Dell PowerEdge R770 and Intel Xeon 6710E

[Baolu Lu]

On 2024/10/10 21:25, Liang, Kan wrote:
> On 2024-10-10 6:10 a.m., Jinpu Wang wrote:
>> Hi Greg,
>>
>>
>> On Thu, Oct 10, 2024 at 11:31 AM Greg KH<gregkh@linuxfoundation.org> wrote:
>>> On Thu, Oct 10, 2024 at 11:13:42AM +0200, Jinpu Wang wrote:
>>>> Hi Greg,
>>>>
>>>> On Thu, Oct 10, 2024 at 11:07 AM Greg KH<gregkh@linuxfoundation.org> wrote:
>>>>> On Thu, Oct 10, 2024 at 09:31:37AM +0200, Jinpu Wang wrote:
>>>>>> Hello all,
>>>>>>
>>>>>> We are experiencing a boot hang issue when booting kernel version
>>>>>> 6.1.83+ on a Dell Inc. PowerEdge R770 equipped with an Intel Xeon
>>>>>> 6710E processor. After extensive testing and use of `git bisect`, we
>>>>>> have traced the issue to commit:
>>>>>>
>>>>>> `586e19c88a0c ("iommu/vt-d: Retrieve IOMMU perfmon capability information")`
>>>>>>
>>>>>> This commit appears to be part of a larger patchset, which can be found here:
>>>>>> [Patchset on lore.kernel.org](https://lore.kernel.org/ 
>>>>>> lkml/7c4b3e4e-1c5d-04f1-1891-84f686c94736@linux.intel.com/T/)
>>>>>>
>>>>>> We attempted to boot with the `intel_iommu=off` option, but the system
>>>>>> hangs in the same manner. However, the system boots successfully after
>>>>>> disabling `CONFIG_INTEL_IOMMU_PERF_EVENTS`.
>>>>> Is there any error messages?  Does the latest 6.6.y tree work properly?
>>>>> If so, why not just use that, no new hardware should be using older
>>>>> kernel trees anyway 🙂
>>>> No error, just hang, I've removed "quiet" and added "debug".
>>>> Yes, the latest 6.6.y tree works for this, but there are other
>>>> problems/dependency we have to solve.
>>> Ok, that implies that we need to add some other patch to 6.1.y, OR we
>>> can revert it from 6.1.y.  Let me know what you think is the better
>>> thing to do.
>>>
>> I think better to revert both:
>> 8c91a4bfc7f8 ("iommu: Fix compilation without CONFIG_IOMMU_INTEL")
> I'm not sure about this one. May need baolu's comments.

I can't find this commit in the mainline kernel. I guess it fixes a
compilation issue in the stable tree? If so, it depends on whether the
issue is still there.

Thanks,
baolu

Re: [regression]Boot Hang on Kernel 6.1.83+ with Dell PowerEdge R770 and Intel Xeon 6710E

[Jinpu Wang]

[-- Attachment #1: Type: text/plain, Size: 2665 bytes --]

Hi Baolu, Liang

Thanks for the reply.

On Thu, Oct 10, 2024 at 4:01 PM Baolu Lu <baolu.lu@linux.intel.com> wrote:
>
> On 2024/10/10 21:25, Liang, Kan wrote:
> > On 2024-10-10 6:10 a.m., Jinpu Wang wrote:
> >> Hi Greg,
> >>
> >>
> >> On Thu, Oct 10, 2024 at 11:31 AM Greg KH<gregkh@linuxfoundation.org> wrote:
> >>> On Thu, Oct 10, 2024 at 11:13:42AM +0200, Jinpu Wang wrote:
> >>>> Hi Greg,
> >>>>
> >>>> On Thu, Oct 10, 2024 at 11:07 AM Greg KH<gregkh@linuxfoundation.org> wrote:
> >>>>> On Thu, Oct 10, 2024 at 09:31:37AM +0200, Jinpu Wang wrote:
> >>>>>> Hello all,
> >>>>>>
> >>>>>> We are experiencing a boot hang issue when booting kernel version
> >>>>>> 6.1.83+ on a Dell Inc. PowerEdge R770 equipped with an Intel Xeon
> >>>>>> 6710E processor. After extensive testing and use of `git bisect`, we
> >>>>>> have traced the issue to commit:
> >>>>>>
> >>>>>> `586e19c88a0c ("iommu/vt-d: Retrieve IOMMU perfmon capability information")`
> >>>>>>
> >>>>>> This commit appears to be part of a larger patchset, which can be found here:
> >>>>>> [Patchset on lore.kernel.org](https://lore.kernel.org/
> >>>>>> lkml/7c4b3e4e-1c5d-04f1-1891-84f686c94736@linux.intel.com/T/)
> >>>>>>
> >>>>>> We attempted to boot with the `intel_iommu=off` option, but the system
> >>>>>> hangs in the same manner. However, the system boots successfully after
> >>>>>> disabling `CONFIG_INTEL_IOMMU_PERF_EVENTS`.
> >>>>> Is there any error messages?  Does the latest 6.6.y tree work properly?
> >>>>> If so, why not just use that, no new hardware should be using older
> >>>>> kernel trees anyway 🙂
> >>>> No error, just hang, I've removed "quiet" and added "debug".
> >>>> Yes, the latest 6.6.y tree works for this, but there are other
> >>>> problems/dependency we have to solve.
> >>> Ok, that implies that we need to add some other patch to 6.1.y, OR we
> >>> can revert it from 6.1.y.  Let me know what you think is the better
> >>> thing to do.
> >>>
> >> I think better to revert both:
> >> 8c91a4bfc7f8 ("iommu: Fix compilation without CONFIG_IOMMU_INTEL")
> > I'm not sure about this one. May need baolu's comments.
>
> I can't find this commit in the mainline kernel. I guess it fixes a
> compilation issue in the stable tree? If so, it depends on whether the
> issue is still there.
>
> Thanks,
> baolu

Both commits are hash from stable tree for linux-6.1.y branch.
I tried only revert  586e19c88a0c ("iommu/vt-d: Retrieve IOMMU perfmon
capability information")

There is a minor conflict in the Makefile, but it's easy to fix. I
attached the patch below,
Greg please consider including it.

Thx!

[-- Attachment #2: 0001-Revert-iommu-vt-d-Retrieve-IOMMU-perfmon-capability-.patch --]
[-- Type: text/x-patch, Size: 12813 bytes --]

From 286b2d88de310423b2cda454f327b3fd3600b56d Mon Sep 17 00:00:00 2001
From: Jack Wang <jinpu.wang@ionos.com>
Date: Fri, 11 Oct 2024 07:10:34 +0200
Subject: [PATCH] Revert "iommu/vt-d: Retrieve IOMMU perfmon capability
 information"

This reverts commit 586e19c88a0cb58b6ff45ae085b3dd200d862153.

This commit is pulled in due to dependency for:
8c91a4bfc7f8 ("iommu: Fix compilation without CONFIG_IOMMU_INTEL")

But the patch itself is part of a patchset, should not only include one,
and it lead to boot hang on on Kernel 6.1.83+ with Dell PowerEdge R770
and Intel Xeon 6710E, so revert it for stable 6.1.112

Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
---
 drivers/iommu/intel/Kconfig   |  11 ---
 drivers/iommu/intel/Makefile  |   1 -
 drivers/iommu/intel/dmar.c    |   7 --
 drivers/iommu/intel/iommu.h   |  43 +--------
 drivers/iommu/intel/perfmon.c | 172 ----------------------------------
 drivers/iommu/intel/perfmon.h |  40 --------
 6 files changed, 1 insertion(+), 273 deletions(-)
 delete mode 100644 drivers/iommu/intel/perfmon.c
 delete mode 100644 drivers/iommu/intel/perfmon.h

diff --git a/drivers/iommu/intel/Kconfig b/drivers/iommu/intel/Kconfig
index 12e1e90fdae1..b7dff5092fd2 100644
--- a/drivers/iommu/intel/Kconfig
+++ b/drivers/iommu/intel/Kconfig
@@ -96,15 +96,4 @@ config INTEL_IOMMU_SCALABLE_MODE_DEFAULT_ON
 	  passing intel_iommu=sm_on to the kernel. If not sure, please use
 	  the default value.
 
-config INTEL_IOMMU_PERF_EVENTS
-	def_bool y
-	bool "Intel IOMMU performance events"
-	depends on INTEL_IOMMU && PERF_EVENTS
-	help
-	  Selecting this option will enable the performance monitoring
-	  infrastructure in the Intel IOMMU. It collects information about
-	  key events occurring during operation of the remapping hardware,
-	  to aid performance tuning and debug. These are available on modern
-	  processors which support Intel VT-d 4.0 and later.
-
 endif # INTEL_IOMMU
diff --git a/drivers/iommu/intel/Makefile b/drivers/iommu/intel/Makefile
index 29d26a437132..1e592655759d 100644
--- a/drivers/iommu/intel/Makefile
+++ b/drivers/iommu/intel/Makefile
@@ -8,4 +8,3 @@ obj-$(CONFIG_INTEL_IOMMU_SVM) += svm.o
 ifdef CONFIG_INTEL_IOMMU
 obj-$(CONFIG_IRQ_REMAP) += irq_remapping.o
 endif
-obj-$(CONFIG_INTEL_IOMMU_PERF_EVENTS) += perfmon.o
diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c
index 345c161ffb27..9c33f1d62ed9 100644
--- a/drivers/iommu/intel/dmar.c
+++ b/drivers/iommu/intel/dmar.c
@@ -34,7 +34,6 @@
 #include "../irq_remapping.h"
 #include "perf.h"
 #include "trace.h"
-#include "perfmon.h"
 
 typedef int (*dmar_res_handler_t)(struct acpi_dmar_header *, void *);
 struct dmar_res_callback {
@@ -1105,9 +1104,6 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd)
 	if (sts & DMA_GSTS_QIES)
 		iommu->gcmd |= DMA_GCMD_QIE;
 
-	if (alloc_iommu_pmu(iommu))
-		pr_debug("Cannot alloc PMU for iommu (seq_id = %d)\n", iommu->seq_id);
-
 	raw_spin_lock_init(&iommu->register_lock);
 
 	/*
@@ -1135,7 +1131,6 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd)
 err_sysfs:
 	iommu_device_sysfs_remove(&iommu->iommu);
 err_unmap:
-	free_iommu_pmu(iommu);
 	unmap_iommu(iommu);
 error_free_seq_id:
 	ida_free(&dmar_seq_ids, iommu->seq_id);
@@ -1151,8 +1146,6 @@ static void free_iommu(struct intel_iommu *iommu)
 		iommu_device_sysfs_remove(&iommu->iommu);
 	}
 
-	free_iommu_pmu(iommu);
-
 	if (iommu->irq) {
 		if (iommu->pr_irq) {
 			free_irq(iommu->pr_irq, iommu);
diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index c1348bedab3b..c99cb715bd9a 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -125,11 +125,6 @@
 #define DMAR_MTRR_PHYSMASK8_REG 0x208
 #define DMAR_MTRR_PHYSBASE9_REG 0x210
 #define DMAR_MTRR_PHYSMASK9_REG 0x218
-#define DMAR_PERFCAP_REG	0x300
-#define DMAR_PERFCFGOFF_REG	0x310
-#define DMAR_PERFOVFOFF_REG	0x318
-#define DMAR_PERFCNTROFF_REG	0x31c
-#define DMAR_PERFEVNTCAP_REG	0x380
 #define DMAR_VCCAP_REG		0xe30 /* Virtual command capability register */
 #define DMAR_VCMD_REG		0xe00 /* Virtual command register */
 #define DMAR_VCRSP_REG		0xe10 /* Virtual command response register */
@@ -153,7 +148,6 @@
  */
 #define cap_esrtps(c)		(((c) >> 63) & 1)
 #define cap_esirtps(c)		(((c) >> 62) & 1)
-#define cap_ecmds(c)		(((c) >> 61) & 1)
 #define cap_fl5lp_support(c)	(((c) >> 60) & 1)
 #define cap_pi_support(c)	(((c) >> 59) & 1)
 #define cap_fl1gp_support(c)	(((c) >> 56) & 1)
@@ -185,8 +179,7 @@
  * Extended Capability Register
  */
 
-#define ecap_pms(e)		(((e) >> 51) & 0x1)
-#define ecap_rps(e)		(((e) >> 49) & 0x1)
+#define	ecap_rps(e)		(((e) >> 49) & 0x1)
 #define ecap_smpwc(e)		(((e) >> 48) & 0x1)
 #define ecap_flts(e)		(((e) >> 47) & 0x1)
 #define ecap_slts(e)		(((e) >> 46) & 0x1)
@@ -217,22 +210,6 @@
 #define ecap_max_handle_mask(e) (((e) >> 20) & 0xf)
 #define ecap_sc_support(e)	(((e) >> 7) & 0x1) /* Snooping Control */
 
-/*
- * Decoding Perf Capability Register
- */
-#define pcap_num_cntr(p)	((p) & 0xffff)
-#define pcap_cntr_width(p)	(((p) >> 16) & 0x7f)
-#define pcap_num_event_group(p)	(((p) >> 24) & 0x1f)
-#define pcap_filters_mask(p)	(((p) >> 32) & 0x1f)
-#define pcap_interrupt(p)	(((p) >> 50) & 0x1)
-/* The counter stride is calculated as 2 ^ (x+10) bytes */
-#define pcap_cntr_stride(p)	(1ULL << ((((p) >> 52) & 0x7) + 10))
-
-/*
- * Decoding Perf Event Capability Register
- */
-#define pecap_es(p)		((p) & 0xfffffff)
-
 /* Virtual command interface capability */
 #define vccap_pasid(v)		(((v) & DMA_VCS_PAS)) /* PASID allocation */
 
@@ -584,22 +561,6 @@ struct dmar_domain {
 					   iommu core */
 };
 
-struct iommu_pmu {
-	struct intel_iommu	*iommu;
-	u32			num_cntr;	/* Number of counters */
-	u32			num_eg;		/* Number of event group */
-	u32			cntr_width;	/* Counter width */
-	u32			cntr_stride;	/* Counter Stride */
-	u32			filter;		/* Bitmask of filter support */
-	void __iomem		*base;		/* the PerfMon base address */
-	void __iomem		*cfg_reg;	/* counter configuration base address */
-	void __iomem		*cntr_reg;	/* counter 0 address*/
-	void __iomem		*overflow;	/* overflow status register */
-
-	u64			*evcap;		/* Indicates all supported events */
-	u32			**cntr_evcap;	/* Supported events of each counter. */
-};
-
 struct intel_iommu {
 	void __iomem	*reg; /* Pointer to hardware regs, virtual addr */
 	u64 		reg_phys; /* physical address of hw register set */
@@ -647,8 +608,6 @@ struct intel_iommu {
 
 	struct dmar_drhd_unit *drhd;
 	void *perf_statistic;
-
-	struct iommu_pmu *pmu;
 };
 
 /* PCI domain-device relationship */
diff --git a/drivers/iommu/intel/perfmon.c b/drivers/iommu/intel/perfmon.c
deleted file mode 100644
index db5791a54455..000000000000
--- a/drivers/iommu/intel/perfmon.c
+++ /dev/null
@@ -1,172 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * Support Intel IOMMU PerfMon
- * Copyright(c) 2023 Intel Corporation.
- */
-#define pr_fmt(fmt)	"DMAR: " fmt
-#define dev_fmt(fmt)	pr_fmt(fmt)
-
-#include <linux/dmar.h>
-#include "iommu.h"
-#include "perfmon.h"
-
-static inline void __iomem *
-get_perf_reg_address(struct intel_iommu *iommu, u32 offset)
-{
-	u32 off = dmar_readl(iommu->reg + offset);
-
-	return iommu->reg + off;
-}
-
-int alloc_iommu_pmu(struct intel_iommu *iommu)
-{
-	struct iommu_pmu *iommu_pmu;
-	int i, j, ret;
-	u64 perfcap;
-	u32 cap;
-
-	if (!ecap_pms(iommu->ecap))
-		return 0;
-
-	/* The IOMMU PMU requires the ECMD support as well */
-	if (!cap_ecmds(iommu->cap))
-		return -ENODEV;
-
-	perfcap = dmar_readq(iommu->reg + DMAR_PERFCAP_REG);
-	/* The performance monitoring is not supported. */
-	if (!perfcap)
-		return -ENODEV;
-
-	/* Sanity check for the number of the counters and event groups */
-	if (!pcap_num_cntr(perfcap) || !pcap_num_event_group(perfcap))
-		return -ENODEV;
-
-	/* The interrupt on overflow is required */
-	if (!pcap_interrupt(perfcap))
-		return -ENODEV;
-
-	iommu_pmu = kzalloc(sizeof(*iommu_pmu), GFP_KERNEL);
-	if (!iommu_pmu)
-		return -ENOMEM;
-
-	iommu_pmu->num_cntr = pcap_num_cntr(perfcap);
-	iommu_pmu->cntr_width = pcap_cntr_width(perfcap);
-	iommu_pmu->filter = pcap_filters_mask(perfcap);
-	iommu_pmu->cntr_stride = pcap_cntr_stride(perfcap);
-	iommu_pmu->num_eg = pcap_num_event_group(perfcap);
-
-	iommu_pmu->evcap = kcalloc(iommu_pmu->num_eg, sizeof(u64), GFP_KERNEL);
-	if (!iommu_pmu->evcap) {
-		ret = -ENOMEM;
-		goto free_pmu;
-	}
-
-	/* Parse event group capabilities */
-	for (i = 0; i < iommu_pmu->num_eg; i++) {
-		u64 pcap;
-
-		pcap = dmar_readq(iommu->reg + DMAR_PERFEVNTCAP_REG +
-				  i * IOMMU_PMU_CAP_REGS_STEP);
-		iommu_pmu->evcap[i] = pecap_es(pcap);
-	}
-
-	iommu_pmu->cntr_evcap = kcalloc(iommu_pmu->num_cntr, sizeof(u32 *), GFP_KERNEL);
-	if (!iommu_pmu->cntr_evcap) {
-		ret = -ENOMEM;
-		goto free_pmu_evcap;
-	}
-	for (i = 0; i < iommu_pmu->num_cntr; i++) {
-		iommu_pmu->cntr_evcap[i] = kcalloc(iommu_pmu->num_eg, sizeof(u32), GFP_KERNEL);
-		if (!iommu_pmu->cntr_evcap[i]) {
-			ret = -ENOMEM;
-			goto free_pmu_cntr_evcap;
-		}
-		/*
-		 * Set to the global capabilities, will adjust according
-		 * to per-counter capabilities later.
-		 */
-		for (j = 0; j < iommu_pmu->num_eg; j++)
-			iommu_pmu->cntr_evcap[i][j] = (u32)iommu_pmu->evcap[j];
-	}
-
-	iommu_pmu->cfg_reg = get_perf_reg_address(iommu, DMAR_PERFCFGOFF_REG);
-	iommu_pmu->cntr_reg = get_perf_reg_address(iommu, DMAR_PERFCNTROFF_REG);
-	iommu_pmu->overflow = get_perf_reg_address(iommu, DMAR_PERFOVFOFF_REG);
-
-	/*
-	 * Check per-counter capabilities. All counters should have the
-	 * same capabilities on Interrupt on Overflow Support and Counter
-	 * Width.
-	 */
-	for (i = 0; i < iommu_pmu->num_cntr; i++) {
-		cap = dmar_readl(iommu_pmu->cfg_reg +
-				 i * IOMMU_PMU_CFG_OFFSET +
-				 IOMMU_PMU_CFG_CNTRCAP_OFFSET);
-		if (!iommu_cntrcap_pcc(cap))
-			continue;
-
-		/*
-		 * It's possible that some counters have a different
-		 * capability because of e.g., HW bug. Check the corner
-		 * case here and simply drop those counters.
-		 */
-		if ((iommu_cntrcap_cw(cap) != iommu_pmu->cntr_width) ||
-		    !iommu_cntrcap_ios(cap)) {
-			iommu_pmu->num_cntr = i;
-			pr_warn("PMU counter capability inconsistent, counter number reduced to %d\n",
-				iommu_pmu->num_cntr);
-		}
-
-		/* Clear the pre-defined events group */
-		for (j = 0; j < iommu_pmu->num_eg; j++)
-			iommu_pmu->cntr_evcap[i][j] = 0;
-
-		/* Override with per-counter event capabilities */
-		for (j = 0; j < iommu_cntrcap_egcnt(cap); j++) {
-			cap = dmar_readl(iommu_pmu->cfg_reg + i * IOMMU_PMU_CFG_OFFSET +
-					 IOMMU_PMU_CFG_CNTREVCAP_OFFSET +
-					 (j * IOMMU_PMU_OFF_REGS_STEP));
-			iommu_pmu->cntr_evcap[i][iommu_event_group(cap)] = iommu_event_select(cap);
-			/*
-			 * Some events may only be supported by a specific counter.
-			 * Track them in the evcap as well.
-			 */
-			iommu_pmu->evcap[iommu_event_group(cap)] |= iommu_event_select(cap);
-		}
-	}
-
-	iommu_pmu->iommu = iommu;
-	iommu->pmu = iommu_pmu;
-
-	return 0;
-
-free_pmu_cntr_evcap:
-	for (i = 0; i < iommu_pmu->num_cntr; i++)
-		kfree(iommu_pmu->cntr_evcap[i]);
-	kfree(iommu_pmu->cntr_evcap);
-free_pmu_evcap:
-	kfree(iommu_pmu->evcap);
-free_pmu:
-	kfree(iommu_pmu);
-
-	return ret;
-}
-
-void free_iommu_pmu(struct intel_iommu *iommu)
-{
-	struct iommu_pmu *iommu_pmu = iommu->pmu;
-
-	if (!iommu_pmu)
-		return;
-
-	if (iommu_pmu->evcap) {
-		int i;
-
-		for (i = 0; i < iommu_pmu->num_cntr; i++)
-			kfree(iommu_pmu->cntr_evcap[i]);
-		kfree(iommu_pmu->cntr_evcap);
-	}
-	kfree(iommu_pmu->evcap);
-	kfree(iommu_pmu);
-	iommu->pmu = NULL;
-}
diff --git a/drivers/iommu/intel/perfmon.h b/drivers/iommu/intel/perfmon.h
deleted file mode 100644
index 4b0d9c1fea6f..000000000000
--- a/drivers/iommu/intel/perfmon.h
+++ /dev/null
@@ -1,40 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-
-/*
- * PERFCFGOFF_REG, PERFFRZOFF_REG
- * PERFOVFOFF_REG, PERFCNTROFF_REG
- */
-#define IOMMU_PMU_NUM_OFF_REGS			4
-#define IOMMU_PMU_OFF_REGS_STEP			4
-
-#define IOMMU_PMU_CFG_OFFSET			0x100
-#define IOMMU_PMU_CFG_CNTRCAP_OFFSET		0x80
-#define IOMMU_PMU_CFG_CNTREVCAP_OFFSET		0x84
-#define IOMMU_PMU_CFG_SIZE			0x8
-#define IOMMU_PMU_CFG_FILTERS_OFFSET		0x4
-
-#define IOMMU_PMU_CAP_REGS_STEP			8
-
-#define iommu_cntrcap_pcc(p)			((p) & 0x1)
-#define iommu_cntrcap_cw(p)			(((p) >> 8) & 0xff)
-#define iommu_cntrcap_ios(p)			(((p) >> 16) & 0x1)
-#define iommu_cntrcap_egcnt(p)			(((p) >> 28) & 0xf)
-
-#define iommu_event_select(p)			((p) & 0xfffffff)
-#define iommu_event_group(p)			(((p) >> 28) & 0xf)
-
-#ifdef CONFIG_INTEL_IOMMU_PERF_EVENTS
-int alloc_iommu_pmu(struct intel_iommu *iommu);
-void free_iommu_pmu(struct intel_iommu *iommu);
-#else
-static inline int
-alloc_iommu_pmu(struct intel_iommu *iommu)
-{
-	return 0;
-}
-
-static inline void
-free_iommu_pmu(struct intel_iommu *iommu)
-{
-}
-#endif /* CONFIG_INTEL_IOMMU_PERF_EVENTS */
-- 
2.43.0

Re: [regression]Boot Hang on Kernel 6.1.83+ with Dell PowerEdge R770 and Intel Xeon 6710E

[Greg KH]

On Thu, Oct 10, 2024 at 10:00:21PM +0800, Baolu Lu wrote:
> On 2024/10/10 21:25, Liang, Kan wrote:
> > On 2024-10-10 6:10 a.m., Jinpu Wang wrote:
> > > Hi Greg,
> > > 
> > > 
> > > On Thu, Oct 10, 2024 at 11:31 AM Greg KH<gregkh@linuxfoundation.org> wrote:
> > > > On Thu, Oct 10, 2024 at 11:13:42AM +0200, Jinpu Wang wrote:
> > > > > Hi Greg,
> > > > > 
> > > > > On Thu, Oct 10, 2024 at 11:07 AM Greg KH<gregkh@linuxfoundation.org> wrote:
> > > > > > On Thu, Oct 10, 2024 at 09:31:37AM +0200, Jinpu Wang wrote:
> > > > > > > Hello all,
> > > > > > > 
> > > > > > > We are experiencing a boot hang issue when booting kernel version
> > > > > > > 6.1.83+ on a Dell Inc. PowerEdge R770 equipped with an Intel Xeon
> > > > > > > 6710E processor. After extensive testing and use of `git bisect`, we
> > > > > > > have traced the issue to commit:
> > > > > > > 
> > > > > > > `586e19c88a0c ("iommu/vt-d: Retrieve IOMMU perfmon capability information")`
> > > > > > > 
> > > > > > > This commit appears to be part of a larger patchset, which can be found here:
> > > > > > > [Patchset on
> > > > > > > lore.kernel.org](https://lore.kernel.org/
> > > > > > > lkml/7c4b3e4e-1c5d-04f1-1891-84f686c94736@linux.intel.com/T/)
> > > > > > > 
> > > > > > > We attempted to boot with the `intel_iommu=off` option, but the system
> > > > > > > hangs in the same manner. However, the system boots successfully after
> > > > > > > disabling `CONFIG_INTEL_IOMMU_PERF_EVENTS`.
> > > > > > Is there any error messages?  Does the latest 6.6.y tree work properly?
> > > > > > If so, why not just use that, no new hardware should be using older
> > > > > > kernel trees anyway 🙂
> > > > > No error, just hang, I've removed "quiet" and added "debug".
> > > > > Yes, the latest 6.6.y tree works for this, but there are other
> > > > > problems/dependency we have to solve.
> > > > Ok, that implies that we need to add some other patch to 6.1.y, OR we
> > > > can revert it from 6.1.y.  Let me know what you think is the better
> > > > thing to do.
> > > > 
> > > I think better to revert both:
> > > 8c91a4bfc7f8 ("iommu: Fix compilation without CONFIG_IOMMU_INTEL")
> > I'm not sure about this one. May need baolu's comments.
> 
> I can't find this commit in the mainline kernel. I guess it fixes a
> compilation issue in the stable tree? If so, it depends on whether the
> issue is still there.

It is commit 70bad345e622 ("iommu: Fix compilation without
CONFIG_IOMMU_INTEL") in Linus's tree.

thanks,

greg k-h

Re: [regression]Boot Hang on Kernel 6.1.83+ with Dell PowerEdge R770 and Intel Xeon 6710E

[Greg KH]

On Thu, Oct 10, 2024 at 12:10:49PM +0200, Jinpu Wang wrote:
> Hi Greg,
> 
> 
> On Thu, Oct 10, 2024 at 11:31 AM Greg KH <gregkh@linuxfoundation.org> wrote:
> >
> > On Thu, Oct 10, 2024 at 11:13:42AM +0200, Jinpu Wang wrote:
> > > Hi Greg,
> > >
> > > On Thu, Oct 10, 2024 at 11:07 AM Greg KH <gregkh@linuxfoundation.org> wrote:
> > > >
> > > > On Thu, Oct 10, 2024 at 09:31:37AM +0200, Jinpu Wang wrote:
> > > > > Hello all,
> > > > >
> > > > > We are experiencing a boot hang issue when booting kernel version
> > > > > 6.1.83+ on a Dell Inc. PowerEdge R770 equipped with an Intel Xeon
> > > > > 6710E processor. After extensive testing and use of `git bisect`, we
> > > > > have traced the issue to commit:
> > > > >
> > > > > `586e19c88a0c ("iommu/vt-d: Retrieve IOMMU perfmon capability information")`
> > > > >
> > > > > This commit appears to be part of a larger patchset, which can be found here:
> > > > > [Patchset on lore.kernel.org](https://lore.kernel.org/lkml/7c4b3e4e-1c5d-04f1-1891-84f686c94736@linux.intel.com/T/)
> > > > >
> > > > > We attempted to boot with the `intel_iommu=off` option, but the system
> > > > > hangs in the same manner. However, the system boots successfully after
> > > > > disabling `CONFIG_INTEL_IOMMU_PERF_EVENTS`.
> > > >
> > > > Is there any error messages?  Does the latest 6.6.y tree work properly?
> > > > If so, why not just use that, no new hardware should be using older
> > > > kernel trees anyway :)
> > > No error, just hang, I've removed "quiet" and added "debug".
> > > Yes, the latest 6.6.y tree works for this, but there are other
> > > problems/dependency we have to solve.
> >
> > Ok, that implies that we need to add some other patch to 6.1.y, OR we
> > can revert it from 6.1.y.  Let me know what you think is the better
> > thing to do.
> >
> I think better to revert both:
> 8c91a4bfc7f8 ("iommu: Fix compilation without CONFIG_IOMMU_INTEL")
> 586e19c88a0c ("iommu/vt-d: Retrieve IOMMU perfmon capability information")

Can you send reverts for these, or do you need us to do this for you?

thanks,

greg k-h

Re: [regression]Boot Hang on Kernel 6.1.83+ with Dell PowerEdge R770 and Intel Xeon 6710E

[Jinpu Wang]

[-- Attachment #1: Type: text/plain, Size: 2994 bytes --]

Hi Greg,


On Fri, Oct 11, 2024 at 7:22 AM Jinpu Wang <jinpu.wang@ionos.com> wrote:
>
> Hi Baolu, Liang
>
> Thanks for the reply.
>
> On Thu, Oct 10, 2024 at 4:01 PM Baolu Lu <baolu.lu@linux.intel.com> wrote:
> >
> > On 2024/10/10 21:25, Liang, Kan wrote:
> > > On 2024-10-10 6:10 a.m., Jinpu Wang wrote:
> > >> Hi Greg,
> > >>
> > >>
> > >> On Thu, Oct 10, 2024 at 11:31 AM Greg KH<gregkh@linuxfoundation.org> wrote:
> > >>> On Thu, Oct 10, 2024 at 11:13:42AM +0200, Jinpu Wang wrote:
> > >>>> Hi Greg,
> > >>>>
> > >>>> On Thu, Oct 10, 2024 at 11:07 AM Greg KH<gregkh@linuxfoundation.org> wrote:
> > >>>>> On Thu, Oct 10, 2024 at 09:31:37AM +0200, Jinpu Wang wrote:
> > >>>>>> Hello all,
> > >>>>>>
> > >>>>>> We are experiencing a boot hang issue when booting kernel version
> > >>>>>> 6.1.83+ on a Dell Inc. PowerEdge R770 equipped with an Intel Xeon
> > >>>>>> 6710E processor. After extensive testing and use of `git bisect`, we
> > >>>>>> have traced the issue to commit:
> > >>>>>>
> > >>>>>> `586e19c88a0c ("iommu/vt-d: Retrieve IOMMU perfmon capability information")`
> > >>>>>>
> > >>>>>> This commit appears to be part of a larger patchset, which can be found here:
> > >>>>>> [Patchset on lore.kernel.org](https://lore.kernel.org/
> > >>>>>> lkml/7c4b3e4e-1c5d-04f1-1891-84f686c94736@linux.intel.com/T/)
> > >>>>>>
> > >>>>>> We attempted to boot with the `intel_iommu=off` option, but the system
> > >>>>>> hangs in the same manner. However, the system boots successfully after
> > >>>>>> disabling `CONFIG_INTEL_IOMMU_PERF_EVENTS`.
> > >>>>> Is there any error messages?  Does the latest 6.6.y tree work properly?
> > >>>>> If so, why not just use that, no new hardware should be using older
> > >>>>> kernel trees anyway 🙂
> > >>>> No error, just hang, I've removed "quiet" and added "debug".
> > >>>> Yes, the latest 6.6.y tree works for this, but there are other
> > >>>> problems/dependency we have to solve.
> > >>> Ok, that implies that we need to add some other patch to 6.1.y, OR we
> > >>> can revert it from 6.1.y.  Let me know what you think is the better
> > >>> thing to do.
> > >>>
> > >> I think better to revert both:
> > >> 8c91a4bfc7f8 ("iommu: Fix compilation without CONFIG_IOMMU_INTEL")
> > > I'm not sure about this one. May need baolu's comments.
> >
> > I can't find this commit in the mainline kernel. I guess it fixes a
> > compilation issue in the stable tree? If so, it depends on whether the
> > issue is still there.
> >
> > Thanks,
> > baolu
>
> Both commits are hash from stable tree for linux-6.1.y branch.
> I tried only revert  586e19c88a0c ("iommu/vt-d: Retrieve IOMMU perfmon
> capability information")
>
> There is a minor conflict in the Makefile, but it's easy to fix. I
> attached the patch below,
> Greg please consider including it.
>
> Thx!
I'm attaching the revert here again, maybe you missed the email,
please consider to include it in 6.1.y.

Thx!

[-- Attachment #2: 0001-Revert-iommu-vt-d-Retrieve-IOMMU-perfmon-capability-.patch --]
[-- Type: text/x-patch, Size: 12813 bytes --]

From 286b2d88de310423b2cda454f327b3fd3600b56d Mon Sep 17 00:00:00 2001
From: Jack Wang <jinpu.wang@ionos.com>
Date: Fri, 11 Oct 2024 07:10:34 +0200
Subject: [PATCH] Revert "iommu/vt-d: Retrieve IOMMU perfmon capability
 information"

This reverts commit 586e19c88a0cb58b6ff45ae085b3dd200d862153.

This commit is pulled in due to dependency for:
8c91a4bfc7f8 ("iommu: Fix compilation without CONFIG_IOMMU_INTEL")

But the patch itself is part of a patchset, should not only include one,
and it lead to boot hang on on Kernel 6.1.83+ with Dell PowerEdge R770
and Intel Xeon 6710E, so revert it for stable 6.1.112

Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
---
 drivers/iommu/intel/Kconfig   |  11 ---
 drivers/iommu/intel/Makefile  |   1 -
 drivers/iommu/intel/dmar.c    |   7 --
 drivers/iommu/intel/iommu.h   |  43 +--------
 drivers/iommu/intel/perfmon.c | 172 ----------------------------------
 drivers/iommu/intel/perfmon.h |  40 --------
 6 files changed, 1 insertion(+), 273 deletions(-)
 delete mode 100644 drivers/iommu/intel/perfmon.c
 delete mode 100644 drivers/iommu/intel/perfmon.h

diff --git a/drivers/iommu/intel/Kconfig b/drivers/iommu/intel/Kconfig
index 12e1e90fdae1..b7dff5092fd2 100644
--- a/drivers/iommu/intel/Kconfig
+++ b/drivers/iommu/intel/Kconfig
@@ -96,15 +96,4 @@ config INTEL_IOMMU_SCALABLE_MODE_DEFAULT_ON
 	  passing intel_iommu=sm_on to the kernel. If not sure, please use
 	  the default value.
 
-config INTEL_IOMMU_PERF_EVENTS
-	def_bool y
-	bool "Intel IOMMU performance events"
-	depends on INTEL_IOMMU && PERF_EVENTS
-	help
-	  Selecting this option will enable the performance monitoring
-	  infrastructure in the Intel IOMMU. It collects information about
-	  key events occurring during operation of the remapping hardware,
-	  to aid performance tuning and debug. These are available on modern
-	  processors which support Intel VT-d 4.0 and later.
-
 endif # INTEL_IOMMU
diff --git a/drivers/iommu/intel/Makefile b/drivers/iommu/intel/Makefile
index 29d26a437132..1e592655759d 100644
--- a/drivers/iommu/intel/Makefile
+++ b/drivers/iommu/intel/Makefile
@@ -8,4 +8,3 @@ obj-$(CONFIG_INTEL_IOMMU_SVM) += svm.o
 ifdef CONFIG_INTEL_IOMMU
 obj-$(CONFIG_IRQ_REMAP) += irq_remapping.o
 endif
-obj-$(CONFIG_INTEL_IOMMU_PERF_EVENTS) += perfmon.o
diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c
index 345c161ffb27..9c33f1d62ed9 100644
--- a/drivers/iommu/intel/dmar.c
+++ b/drivers/iommu/intel/dmar.c
@@ -34,7 +34,6 @@
 #include "../irq_remapping.h"
 #include "perf.h"
 #include "trace.h"
-#include "perfmon.h"
 
 typedef int (*dmar_res_handler_t)(struct acpi_dmar_header *, void *);
 struct dmar_res_callback {
@@ -1105,9 +1104,6 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd)
 	if (sts & DMA_GSTS_QIES)
 		iommu->gcmd |= DMA_GCMD_QIE;
 
-	if (alloc_iommu_pmu(iommu))
-		pr_debug("Cannot alloc PMU for iommu (seq_id = %d)\n", iommu->seq_id);
-
 	raw_spin_lock_init(&iommu->register_lock);
 
 	/*
@@ -1135,7 +1131,6 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd)
 err_sysfs:
 	iommu_device_sysfs_remove(&iommu->iommu);
 err_unmap:
-	free_iommu_pmu(iommu);
 	unmap_iommu(iommu);
 error_free_seq_id:
 	ida_free(&dmar_seq_ids, iommu->seq_id);
@@ -1151,8 +1146,6 @@ static void free_iommu(struct intel_iommu *iommu)
 		iommu_device_sysfs_remove(&iommu->iommu);
 	}
 
-	free_iommu_pmu(iommu);
-
 	if (iommu->irq) {
 		if (iommu->pr_irq) {
 			free_irq(iommu->pr_irq, iommu);
diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index c1348bedab3b..c99cb715bd9a 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -125,11 +125,6 @@
 #define DMAR_MTRR_PHYSMASK8_REG 0x208
 #define DMAR_MTRR_PHYSBASE9_REG 0x210
 #define DMAR_MTRR_PHYSMASK9_REG 0x218
-#define DMAR_PERFCAP_REG	0x300
-#define DMAR_PERFCFGOFF_REG	0x310
-#define DMAR_PERFOVFOFF_REG	0x318
-#define DMAR_PERFCNTROFF_REG	0x31c
-#define DMAR_PERFEVNTCAP_REG	0x380
 #define DMAR_VCCAP_REG		0xe30 /* Virtual command capability register */
 #define DMAR_VCMD_REG		0xe00 /* Virtual command register */
 #define DMAR_VCRSP_REG		0xe10 /* Virtual command response register */
@@ -153,7 +148,6 @@
  */
 #define cap_esrtps(c)		(((c) >> 63) & 1)
 #define cap_esirtps(c)		(((c) >> 62) & 1)
-#define cap_ecmds(c)		(((c) >> 61) & 1)
 #define cap_fl5lp_support(c)	(((c) >> 60) & 1)
 #define cap_pi_support(c)	(((c) >> 59) & 1)
 #define cap_fl1gp_support(c)	(((c) >> 56) & 1)
@@ -185,8 +179,7 @@
  * Extended Capability Register
  */
 
-#define ecap_pms(e)		(((e) >> 51) & 0x1)
-#define ecap_rps(e)		(((e) >> 49) & 0x1)
+#define	ecap_rps(e)		(((e) >> 49) & 0x1)
 #define ecap_smpwc(e)		(((e) >> 48) & 0x1)
 #define ecap_flts(e)		(((e) >> 47) & 0x1)
 #define ecap_slts(e)		(((e) >> 46) & 0x1)
@@ -217,22 +210,6 @@
 #define ecap_max_handle_mask(e) (((e) >> 20) & 0xf)
 #define ecap_sc_support(e)	(((e) >> 7) & 0x1) /* Snooping Control */
 
-/*
- * Decoding Perf Capability Register
- */
-#define pcap_num_cntr(p)	((p) & 0xffff)
-#define pcap_cntr_width(p)	(((p) >> 16) & 0x7f)
-#define pcap_num_event_group(p)	(((p) >> 24) & 0x1f)
-#define pcap_filters_mask(p)	(((p) >> 32) & 0x1f)
-#define pcap_interrupt(p)	(((p) >> 50) & 0x1)
-/* The counter stride is calculated as 2 ^ (x+10) bytes */
-#define pcap_cntr_stride(p)	(1ULL << ((((p) >> 52) & 0x7) + 10))
-
-/*
- * Decoding Perf Event Capability Register
- */
-#define pecap_es(p)		((p) & 0xfffffff)
-
 /* Virtual command interface capability */
 #define vccap_pasid(v)		(((v) & DMA_VCS_PAS)) /* PASID allocation */
 
@@ -584,22 +561,6 @@ struct dmar_domain {
 					   iommu core */
 };
 
-struct iommu_pmu {
-	struct intel_iommu	*iommu;
-	u32			num_cntr;	/* Number of counters */
-	u32			num_eg;		/* Number of event group */
-	u32			cntr_width;	/* Counter width */
-	u32			cntr_stride;	/* Counter Stride */
-	u32			filter;		/* Bitmask of filter support */
-	void __iomem		*base;		/* the PerfMon base address */
-	void __iomem		*cfg_reg;	/* counter configuration base address */
-	void __iomem		*cntr_reg;	/* counter 0 address*/
-	void __iomem		*overflow;	/* overflow status register */
-
-	u64			*evcap;		/* Indicates all supported events */
-	u32			**cntr_evcap;	/* Supported events of each counter. */
-};
-
 struct intel_iommu {
 	void __iomem	*reg; /* Pointer to hardware regs, virtual addr */
 	u64 		reg_phys; /* physical address of hw register set */
@@ -647,8 +608,6 @@ struct intel_iommu {
 
 	struct dmar_drhd_unit *drhd;
 	void *perf_statistic;
-
-	struct iommu_pmu *pmu;
 };
 
 /* PCI domain-device relationship */
diff --git a/drivers/iommu/intel/perfmon.c b/drivers/iommu/intel/perfmon.c
deleted file mode 100644
index db5791a54455..000000000000
--- a/drivers/iommu/intel/perfmon.c
+++ /dev/null
@@ -1,172 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * Support Intel IOMMU PerfMon
- * Copyright(c) 2023 Intel Corporation.
- */
-#define pr_fmt(fmt)	"DMAR: " fmt
-#define dev_fmt(fmt)	pr_fmt(fmt)
-
-#include <linux/dmar.h>
-#include "iommu.h"
-#include "perfmon.h"
-
-static inline void __iomem *
-get_perf_reg_address(struct intel_iommu *iommu, u32 offset)
-{
-	u32 off = dmar_readl(iommu->reg + offset);
-
-	return iommu->reg + off;
-}
-
-int alloc_iommu_pmu(struct intel_iommu *iommu)
-{
-	struct iommu_pmu *iommu_pmu;
-	int i, j, ret;
-	u64 perfcap;
-	u32 cap;
-
-	if (!ecap_pms(iommu->ecap))
-		return 0;
-
-	/* The IOMMU PMU requires the ECMD support as well */
-	if (!cap_ecmds(iommu->cap))
-		return -ENODEV;
-
-	perfcap = dmar_readq(iommu->reg + DMAR_PERFCAP_REG);
-	/* The performance monitoring is not supported. */
-	if (!perfcap)
-		return -ENODEV;
-
-	/* Sanity check for the number of the counters and event groups */
-	if (!pcap_num_cntr(perfcap) || !pcap_num_event_group(perfcap))
-		return -ENODEV;
-
-	/* The interrupt on overflow is required */
-	if (!pcap_interrupt(perfcap))
-		return -ENODEV;
-
-	iommu_pmu = kzalloc(sizeof(*iommu_pmu), GFP_KERNEL);
-	if (!iommu_pmu)
-		return -ENOMEM;
-
-	iommu_pmu->num_cntr = pcap_num_cntr(perfcap);
-	iommu_pmu->cntr_width = pcap_cntr_width(perfcap);
-	iommu_pmu->filter = pcap_filters_mask(perfcap);
-	iommu_pmu->cntr_stride = pcap_cntr_stride(perfcap);
-	iommu_pmu->num_eg = pcap_num_event_group(perfcap);
-
-	iommu_pmu->evcap = kcalloc(iommu_pmu->num_eg, sizeof(u64), GFP_KERNEL);
-	if (!iommu_pmu->evcap) {
-		ret = -ENOMEM;
-		goto free_pmu;
-	}
-
-	/* Parse event group capabilities */
-	for (i = 0; i < iommu_pmu->num_eg; i++) {
-		u64 pcap;
-
-		pcap = dmar_readq(iommu->reg + DMAR_PERFEVNTCAP_REG +
-				  i * IOMMU_PMU_CAP_REGS_STEP);
-		iommu_pmu->evcap[i] = pecap_es(pcap);
-	}
-
-	iommu_pmu->cntr_evcap = kcalloc(iommu_pmu->num_cntr, sizeof(u32 *), GFP_KERNEL);
-	if (!iommu_pmu->cntr_evcap) {
-		ret = -ENOMEM;
-		goto free_pmu_evcap;
-	}
-	for (i = 0; i < iommu_pmu->num_cntr; i++) {
-		iommu_pmu->cntr_evcap[i] = kcalloc(iommu_pmu->num_eg, sizeof(u32), GFP_KERNEL);
-		if (!iommu_pmu->cntr_evcap[i]) {
-			ret = -ENOMEM;
-			goto free_pmu_cntr_evcap;
-		}
-		/*
-		 * Set to the global capabilities, will adjust according
-		 * to per-counter capabilities later.
-		 */
-		for (j = 0; j < iommu_pmu->num_eg; j++)
-			iommu_pmu->cntr_evcap[i][j] = (u32)iommu_pmu->evcap[j];
-	}
-
-	iommu_pmu->cfg_reg = get_perf_reg_address(iommu, DMAR_PERFCFGOFF_REG);
-	iommu_pmu->cntr_reg = get_perf_reg_address(iommu, DMAR_PERFCNTROFF_REG);
-	iommu_pmu->overflow = get_perf_reg_address(iommu, DMAR_PERFOVFOFF_REG);
-
-	/*
-	 * Check per-counter capabilities. All counters should have the
-	 * same capabilities on Interrupt on Overflow Support and Counter
-	 * Width.
-	 */
-	for (i = 0; i < iommu_pmu->num_cntr; i++) {
-		cap = dmar_readl(iommu_pmu->cfg_reg +
-				 i * IOMMU_PMU_CFG_OFFSET +
-				 IOMMU_PMU_CFG_CNTRCAP_OFFSET);
-		if (!iommu_cntrcap_pcc(cap))
-			continue;
-
-		/*
-		 * It's possible that some counters have a different
-		 * capability because of e.g., HW bug. Check the corner
-		 * case here and simply drop those counters.
-		 */
-		if ((iommu_cntrcap_cw(cap) != iommu_pmu->cntr_width) ||
-		    !iommu_cntrcap_ios(cap)) {
-			iommu_pmu->num_cntr = i;
-			pr_warn("PMU counter capability inconsistent, counter number reduced to %d\n",
-				iommu_pmu->num_cntr);
-		}
-
-		/* Clear the pre-defined events group */
-		for (j = 0; j < iommu_pmu->num_eg; j++)
-			iommu_pmu->cntr_evcap[i][j] = 0;
-
-		/* Override with per-counter event capabilities */
-		for (j = 0; j < iommu_cntrcap_egcnt(cap); j++) {
-			cap = dmar_readl(iommu_pmu->cfg_reg + i * IOMMU_PMU_CFG_OFFSET +
-					 IOMMU_PMU_CFG_CNTREVCAP_OFFSET +
-					 (j * IOMMU_PMU_OFF_REGS_STEP));
-			iommu_pmu->cntr_evcap[i][iommu_event_group(cap)] = iommu_event_select(cap);
-			/*
-			 * Some events may only be supported by a specific counter.
-			 * Track them in the evcap as well.
-			 */
-			iommu_pmu->evcap[iommu_event_group(cap)] |= iommu_event_select(cap);
-		}
-	}
-
-	iommu_pmu->iommu = iommu;
-	iommu->pmu = iommu_pmu;
-
-	return 0;
-
-free_pmu_cntr_evcap:
-	for (i = 0; i < iommu_pmu->num_cntr; i++)
-		kfree(iommu_pmu->cntr_evcap[i]);
-	kfree(iommu_pmu->cntr_evcap);
-free_pmu_evcap:
-	kfree(iommu_pmu->evcap);
-free_pmu:
-	kfree(iommu_pmu);
-
-	return ret;
-}
-
-void free_iommu_pmu(struct intel_iommu *iommu)
-{
-	struct iommu_pmu *iommu_pmu = iommu->pmu;
-
-	if (!iommu_pmu)
-		return;
-
-	if (iommu_pmu->evcap) {
-		int i;
-
-		for (i = 0; i < iommu_pmu->num_cntr; i++)
-			kfree(iommu_pmu->cntr_evcap[i]);
-		kfree(iommu_pmu->cntr_evcap);
-	}
-	kfree(iommu_pmu->evcap);
-	kfree(iommu_pmu);
-	iommu->pmu = NULL;
-}
diff --git a/drivers/iommu/intel/perfmon.h b/drivers/iommu/intel/perfmon.h
deleted file mode 100644
index 4b0d9c1fea6f..000000000000
--- a/drivers/iommu/intel/perfmon.h
+++ /dev/null
@@ -1,40 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-
-/*
- * PERFCFGOFF_REG, PERFFRZOFF_REG
- * PERFOVFOFF_REG, PERFCNTROFF_REG
- */
-#define IOMMU_PMU_NUM_OFF_REGS			4
-#define IOMMU_PMU_OFF_REGS_STEP			4
-
-#define IOMMU_PMU_CFG_OFFSET			0x100
-#define IOMMU_PMU_CFG_CNTRCAP_OFFSET		0x80
-#define IOMMU_PMU_CFG_CNTREVCAP_OFFSET		0x84
-#define IOMMU_PMU_CFG_SIZE			0x8
-#define IOMMU_PMU_CFG_FILTERS_OFFSET		0x4
-
-#define IOMMU_PMU_CAP_REGS_STEP			8
-
-#define iommu_cntrcap_pcc(p)			((p) & 0x1)
-#define iommu_cntrcap_cw(p)			(((p) >> 8) & 0xff)
-#define iommu_cntrcap_ios(p)			(((p) >> 16) & 0x1)
-#define iommu_cntrcap_egcnt(p)			(((p) >> 28) & 0xf)
-
-#define iommu_event_select(p)			((p) & 0xfffffff)
-#define iommu_event_group(p)			(((p) >> 28) & 0xf)
-
-#ifdef CONFIG_INTEL_IOMMU_PERF_EVENTS
-int alloc_iommu_pmu(struct intel_iommu *iommu);
-void free_iommu_pmu(struct intel_iommu *iommu);
-#else
-static inline int
-alloc_iommu_pmu(struct intel_iommu *iommu)
-{
-	return 0;
-}
-
-static inline void
-free_iommu_pmu(struct intel_iommu *iommu)
-{
-}
-#endif /* CONFIG_INTEL_IOMMU_PERF_EVENTS */
-- 
2.43.0

Re: [regression]Boot Hang on Kernel 6.1.83+ with Dell PowerEdge R770 and Intel Xeon 6710E

[Greg KH]

On Mon, Oct 14, 2024 at 11:39:57AM +0200, Jinpu Wang wrote:
> Hi Greg,
> 
> 
> On Fri, Oct 11, 2024 at 7:22 AM Jinpu Wang <jinpu.wang@ionos.com> wrote:
> >
> > Hi Baolu, Liang
> >
> > Thanks for the reply.
> >
> > On Thu, Oct 10, 2024 at 4:01 PM Baolu Lu <baolu.lu@linux.intel.com> wrote:
> > >
> > > On 2024/10/10 21:25, Liang, Kan wrote:
> > > > On 2024-10-10 6:10 a.m., Jinpu Wang wrote:
> > > >> Hi Greg,
> > > >>
> > > >>
> > > >> On Thu, Oct 10, 2024 at 11:31 AM Greg KH<gregkh@linuxfoundation.org> wrote:
> > > >>> On Thu, Oct 10, 2024 at 11:13:42AM +0200, Jinpu Wang wrote:
> > > >>>> Hi Greg,
> > > >>>>
> > > >>>> On Thu, Oct 10, 2024 at 11:07 AM Greg KH<gregkh@linuxfoundation.org> wrote:
> > > >>>>> On Thu, Oct 10, 2024 at 09:31:37AM +0200, Jinpu Wang wrote:
> > > >>>>>> Hello all,
> > > >>>>>>
> > > >>>>>> We are experiencing a boot hang issue when booting kernel version
> > > >>>>>> 6.1.83+ on a Dell Inc. PowerEdge R770 equipped with an Intel Xeon
> > > >>>>>> 6710E processor. After extensive testing and use of `git bisect`, we
> > > >>>>>> have traced the issue to commit:
> > > >>>>>>
> > > >>>>>> `586e19c88a0c ("iommu/vt-d: Retrieve IOMMU perfmon capability information")`
> > > >>>>>>
> > > >>>>>> This commit appears to be part of a larger patchset, which can be found here:
> > > >>>>>> [Patchset on lore.kernel.org](https://lore.kernel.org/
> > > >>>>>> lkml/7c4b3e4e-1c5d-04f1-1891-84f686c94736@linux.intel.com/T/)
> > > >>>>>>
> > > >>>>>> We attempted to boot with the `intel_iommu=off` option, but the system
> > > >>>>>> hangs in the same manner. However, the system boots successfully after
> > > >>>>>> disabling `CONFIG_INTEL_IOMMU_PERF_EVENTS`.
> > > >>>>> Is there any error messages?  Does the latest 6.6.y tree work properly?
> > > >>>>> If so, why not just use that, no new hardware should be using older
> > > >>>>> kernel trees anyway 🙂
> > > >>>> No error, just hang, I've removed "quiet" and added "debug".
> > > >>>> Yes, the latest 6.6.y tree works for this, but there are other
> > > >>>> problems/dependency we have to solve.
> > > >>> Ok, that implies that we need to add some other patch to 6.1.y, OR we
> > > >>> can revert it from 6.1.y.  Let me know what you think is the better
> > > >>> thing to do.
> > > >>>
> > > >> I think better to revert both:
> > > >> 8c91a4bfc7f8 ("iommu: Fix compilation without CONFIG_IOMMU_INTEL")
> > > > I'm not sure about this one. May need baolu's comments.
> > >
> > > I can't find this commit in the mainline kernel. I guess it fixes a
> > > compilation issue in the stable tree? If so, it depends on whether the
> > > issue is still there.
> > >
> > > Thanks,
> > > baolu
> >
> > Both commits are hash from stable tree for linux-6.1.y branch.
> > I tried only revert  586e19c88a0c ("iommu/vt-d: Retrieve IOMMU perfmon
> > capability information")
> >
> > There is a minor conflict in the Makefile, but it's easy to fix. I
> > attached the patch below,
> > Greg please consider including it.
> >
> > Thx!
> I'm attaching the revert here again, maybe you missed the email,
> please consider to include it in 6.1.y.

I did miss that, sorry, now queued up!

greg k-h