[for-4.13] x86/VT-d: Drop unhelpful information in diagnostics
diff mbox series

Message ID 20191011150253.29457-1-andrew.cooper3@citrix.com
State New
Headers show
Series
  • [for-4.13] x86/VT-d: Drop unhelpful information in diagnostics
Related show

Commit Message

Andrew Cooper Oct. 11, 2019, 3:02 p.m. UTC
The virtual address of the base of the IOMMU's regsters is not useful for
diagnostic purposes, and is quite voluminous.  The PCI coordinates is by far
the most useful piece of identifying information.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Wei Liu <wl@xen.org>
CC: Roger Pau Monné <roger.pau@citrix.com>
CC: Jun Nakajima <jun.nakajima@intel.com>
CC: Kevin Tian <kevin.tian@intel.com>
CC: Juergen Gross <jgross@suse.com>

Surrounding printk()s also identify the IOMMU by Xen's internal ID, but that
is also pretty useless information when diagnosing problems.

RFC for-4.13.  This is a nice to have stylistic improvement.
---
 xen/drivers/passthrough/vtd/iommu.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

Comments

Roger Pau Monné Oct. 11, 2019, 3:33 p.m. UTC | #1
On Fri, Oct 11, 2019 at 04:02:53PM +0100, Andrew Cooper wrote:
> The virtual address of the base of the IOMMU's regsters is not useful for
> diagnostic purposes, and is quite voluminous.  The PCI coordinates is by far
> the most useful piece of identifying information.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> ---
> CC: Jan Beulich <JBeulich@suse.com>
> CC: Wei Liu <wl@xen.org>
> CC: Roger Pau Monné <roger.pau@citrix.com>
> CC: Jun Nakajima <jun.nakajima@intel.com>
> CC: Kevin Tian <kevin.tian@intel.com>
> CC: Juergen Gross <jgross@suse.com>
> 
> Surrounding printk()s also identify the IOMMU by Xen's internal ID, but that
> is also pretty useless information when diagnosing problems.
> 
> RFC for-4.13.  This is a nice to have stylistic improvement.

I don't think the register is useful for debugging, at least I have
never used it myself, so:

Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>

Thanks, Roger.
Juergen Gross Oct. 14, 2019, 1:44 p.m. UTC | #2
On 11.10.19 17:02, Andrew Cooper wrote:
> The virtual address of the base of the IOMMU's regsters is not useful for
> diagnostic purposes, and is quite voluminous.  The PCI coordinates is by far
> the most useful piece of identifying information.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

Release-acked-by: Juergen Gross <jgross@suse.com>


Juergen
Jan Beulich Oct. 23, 2019, 2 p.m. UTC | #3
On 11.10.2019 17:33, Roger Pau Monné  wrote:
> On Fri, Oct 11, 2019 at 04:02:53PM +0100, Andrew Cooper wrote:
>> The virtual address of the base of the IOMMU's regsters is not useful for
>> diagnostic purposes, and is quite voluminous.  The PCI coordinates is by far
>> the most useful piece of identifying information.
>>
>> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
>> ---
>> CC: Jan Beulich <JBeulich@suse.com>
>> CC: Wei Liu <wl@xen.org>
>> CC: Roger Pau Monné <roger.pau@citrix.com>
>> CC: Jun Nakajima <jun.nakajima@intel.com>
>> CC: Kevin Tian <kevin.tian@intel.com>
>> CC: Juergen Gross <jgross@suse.com>
>>
>> Surrounding printk()s also identify the IOMMU by Xen's internal ID, but that
>> is also pretty useless information when diagnosing problems.
>>
>> RFC for-4.13.  This is a nice to have stylistic improvement.
> 
> I don't think the register is useful for debugging, at least I have
> never used it myself, so:
> 
> Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>

Seeing that there hasn't been an ack from Kevin, perhaps this
rather simple change can go in without? Just in case
Acked-by: Jan Beulich <jbeulich@suse.com>

Jan
Tian, Kevin Oct. 24, 2019, 12:58 a.m. UTC | #4
> From: Jan Beulich [mailto:jbeulich@suse.com]
> Sent: Wednesday, October 23, 2019 10:00 PM
> 
> On 11.10.2019 17:33, Roger Pau Monné  wrote:
> > On Fri, Oct 11, 2019 at 04:02:53PM +0100, Andrew Cooper wrote:
> >> The virtual address of the base of the IOMMU's regsters is not useful for
> >> diagnostic purposes, and is quite voluminous.  The PCI coordinates is by
> far
> >> the most useful piece of identifying information.
> >>
> >> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> >> ---
> >> CC: Jan Beulich <JBeulich@suse.com>
> >> CC: Wei Liu <wl@xen.org>
> >> CC: Roger Pau Monné <roger.pau@citrix.com>
> >> CC: Jun Nakajima <jun.nakajima@intel.com>
> >> CC: Kevin Tian <kevin.tian@intel.com>
> >> CC: Juergen Gross <jgross@suse.com>
> >>
> >> Surrounding printk()s also identify the IOMMU by Xen's internal ID, but
> that
> >> is also pretty useless information when diagnosing problems.
> >>
> >> RFC for-4.13.  This is a nice to have stylistic improvement.
> >
> > I don't think the register is useful for debugging, at least I have
> > never used it myself, so:
> >
> > Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
> 
> Seeing that there hasn't been an ack from Kevin, perhaps this
> rather simple change can go in without? Just in case
> Acked-by: Jan Beulich <jbeulich@suse.com>
> 

I overlooked at it. Acked-by: Kevin Tian <kevin.tian@intel.com>

Patch
diff mbox series

diff --git a/xen/drivers/passthrough/vtd/iommu.c b/xen/drivers/passthrough/vtd/iommu.c
index f08eec070d..0522ecd3bc 100644
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -842,26 +842,26 @@  static int iommu_page_fault_do_one(struct vtd_iommu *iommu, int type,
     case DMA_REMAP:
         printk(XENLOG_G_WARNING VTDPREFIX
                "DMAR:[%s] Request device [%04x:%02x:%02x.%u] "
-               "fault addr %"PRIx64", iommu reg = %p\n",
+               "fault addr %"PRIx64"\n",
                (type ? "DMA Read" : "DMA Write"),
                seg, PCI_BUS(source_id), PCI_SLOT(source_id),
-               PCI_FUNC(source_id), addr, iommu->reg);
+               PCI_FUNC(source_id), addr);
         kind = "DMAR";
         break;
     case INTR_REMAP:
         printk(XENLOG_G_WARNING VTDPREFIX
                "INTR-REMAP: Request device [%04x:%02x:%02x.%u] "
-               "fault index %"PRIx64", iommu reg = %p\n",
+               "fault index %"PRIx64"\n",
                seg, PCI_BUS(source_id), PCI_SLOT(source_id),
-               PCI_FUNC(source_id), addr >> 48, iommu->reg);
+               PCI_FUNC(source_id), addr >> 48);
         kind = "INTR-REMAP";
         break;
     default:
         printk(XENLOG_G_WARNING VTDPREFIX
                "UNKNOWN: Request device [%04x:%02x:%02x.%u] "
-               "fault addr %"PRIx64", iommu reg = %p\n",
+               "fault addr %"PRIx64"\n",
                seg, PCI_BUS(source_id), PCI_SLOT(source_id),
-               PCI_FUNC(source_id), addr, iommu->reg);
+               PCI_FUNC(source_id), addr);
         kind = "UNKNOWN";
         break;
     }