All of lore.kernel.org
 help / color / mirror / Atom feed
* [PATCH] usertools: add check for IOMMU support in dpdk-devbind
@ 2022-03-08 12:49 Fidaullah Noonari
  2022-03-08 12:56 ` Bruce Richardson
  0 siblings, 1 reply; 3+ messages in thread
From: Fidaullah Noonari @ 2022-03-08 12:49 UTC (permalink / raw)
  To: stephen; +Cc: dev, Fidaullah Noonari

binding with vfio driver, when IOMMU is disabled, causes program to crash.
this patch checks for IOMMU support, if it is disabled, changes vfio
into unsafe noiommu mode and prints a warning message.

Signed-off-by: Fidaullah Noonari <fidaullah.noonari@gmai.com>
---
 usertools/dpdk-devbind.py | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/usertools/dpdk-devbind.py b/usertools/dpdk-devbind.py
index ace4627218..f42eead0c4 100755
--- a/usertools/dpdk-devbind.py
+++ b/usertools/dpdk-devbind.py
@@ -466,6 +466,26 @@ def unbind_all(dev_list, force=False):
         unbind_one(d, force)
 
 
+def check_iommu():
+    """Check if IOMMU is enabled on system"""
+    if len(os.listdir("/sys/class/iommu")) != 0:
+        return True
+    print("Warning: IOMMU support disabled")
+    return False
+
+
+def enable_noiommu_mode():
+    """Enables the noiommu mode for vfio drivers"""
+    filename = "/sys/module/vfio/parameters/enable_unsafe_noiommu_mode"
+    try:
+        f = open(filename, "w")
+    except:
+        sys.exit("Error: unable to enable noiommu mode, could not open '%s'" % filename)
+    f.write("1")
+    f.close()
+    print("Warning: enabling unsafe no IOMMU mode for vfio drivers")
+
+
 def bind_all(dev_list, driver, force=False):
     """Bind method, takes a list of device locations"""
     global devices
@@ -492,6 +512,11 @@ def bind_all(dev_list, driver, force=False):
     except ValueError as ex:
         sys.exit(ex)
 
+    # check for IOMMU support
+    if not check_iommu():
+        if driver == "vfio-pci":
+            enable_noiommu_mode()
+
     for d in dev_list:
         bind_one(d, driver, force)
 
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH] usertools: add check for IOMMU support in dpdk-devbind
  2022-03-08 12:49 [PATCH] usertools: add check for IOMMU support in dpdk-devbind Fidaullah Noonari
@ 2022-03-08 12:56 ` Bruce Richardson
  2022-03-10  4:08   ` Fidaullah Noonari
  0 siblings, 1 reply; 3+ messages in thread
From: Bruce Richardson @ 2022-03-08 12:56 UTC (permalink / raw)
  To: Fidaullah Noonari; +Cc: stephen, dev, Fidaullah Noonari

On Tue, Mar 08, 2022 at 05:49:01PM +0500, Fidaullah Noonari wrote:
> binding with vfio driver, when IOMMU is disabled, causes program to crash.
> this patch checks for IOMMU support, if it is disabled, changes vfio
> into unsafe noiommu mode and prints a warning message.
> 
> Signed-off-by: Fidaullah Noonari <fidaullah.noonari@gmai.com>
> ---
>  usertools/dpdk-devbind.py | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/usertools/dpdk-devbind.py b/usertools/dpdk-devbind.py
> index ace4627218..f42eead0c4 100755
> --- a/usertools/dpdk-devbind.py
> +++ b/usertools/dpdk-devbind.py
> @@ -466,6 +466,26 @@ def unbind_all(dev_list, force=False):
>          unbind_one(d, force)
>  
>  
> +def check_iommu():
> +    """Check if IOMMU is enabled on system"""
> +    if len(os.listdir("/sys/class/iommu")) != 0:
> +        return True
> +    print("Warning: IOMMU support disabled")
> +    return False
> +
> +
> +def enable_noiommu_mode():
> +    """Enables the noiommu mode for vfio drivers"""
> +    filename = "/sys/module/vfio/parameters/enable_unsafe_noiommu_mode"
> +    try:
> +        f = open(filename, "w")
> +    except:
> +        sys.exit("Error: unable to enable noiommu mode, could not open '%s'" % filename)
> +    f.write("1")
> +    f.close()
> +    print("Warning: enabling unsafe no IOMMU mode for vfio drivers")
> +
> +
>  def bind_all(dev_list, driver, force=False):
>      """Bind method, takes a list of device locations"""
>      global devices
> @@ -492,6 +512,11 @@ def bind_all(dev_list, driver, force=False):
>      except ValueError as ex:
>          sys.exit(ex)
>  
> +    # check for IOMMU support
> +    if not check_iommu():
> +        if driver == "vfio-pci":
> +            enable_noiommu_mode()
> +
>      for d in dev_list:
>          bind_one(d, driver, force)
>  
I like the idea of doing this from the script, but I would rather it not
happen by default, since no-iommu reduces the security of the system. In
the normal case, I think it would be best if the script printed an error
message asking the user to enable iommu. We can also then add a flag to
allow the user to explicitly ask for no-iommu mode and take the risk.

/Bruce

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] usertools: add check for IOMMU support in dpdk-devbind
  2022-03-08 12:56 ` Bruce Richardson
@ 2022-03-10  4:08   ` Fidaullah Noonari
  0 siblings, 0 replies; 3+ messages in thread
From: Fidaullah Noonari @ 2022-03-10  4:08 UTC (permalink / raw)
  To: Bruce Richardson; +Cc: stephen, dev

I agree with your suggestion. I would add new flag for noiommu and
submit v2 for the patch.


On Tue, Mar 8, 2022 at 5:57 PM Bruce Richardson
<bruce.richardson@intel.com> wrote:
>
> On Tue, Mar 08, 2022 at 05:49:01PM +0500, Fidaullah Noonari wrote:
> > binding with vfio driver, when IOMMU is disabled, causes program to crash.
> > this patch checks for IOMMU support, if it is disabled, changes vfio
> > into unsafe noiommu mode and prints a warning message.
> >
> > Signed-off-by: Fidaullah Noonari <fidaullah.noonari@gmai.com>
> > ---
> >  usertools/dpdk-devbind.py | 25 +++++++++++++++++++++++++
> >  1 file changed, 25 insertions(+)
> >
> > diff --git a/usertools/dpdk-devbind.py b/usertools/dpdk-devbind.py
> > index ace4627218..f42eead0c4 100755
> > --- a/usertools/dpdk-devbind.py
> > +++ b/usertools/dpdk-devbind.py
> > @@ -466,6 +466,26 @@ def unbind_all(dev_list, force=False):
> >          unbind_one(d, force)
> >
> >
> > +def check_iommu():
> > +    """Check if IOMMU is enabled on system"""
> > +    if len(os.listdir("/sys/class/iommu")) != 0:
> > +        return True
> > +    print("Warning: IOMMU support disabled")
> > +    return False
> > +
> > +
> > +def enable_noiommu_mode():
> > +    """Enables the noiommu mode for vfio drivers"""
> > +    filename = "/sys/module/vfio/parameters/enable_unsafe_noiommu_mode"
> > +    try:
> > +        f = open(filename, "w")
> > +    except:
> > +        sys.exit("Error: unable to enable noiommu mode, could not open '%s'" % filename)
> > +    f.write("1")
> > +    f.close()
> > +    print("Warning: enabling unsafe no IOMMU mode for vfio drivers")
> > +
> > +
> >  def bind_all(dev_list, driver, force=False):
> >      """Bind method, takes a list of device locations"""
> >      global devices
> > @@ -492,6 +512,11 @@ def bind_all(dev_list, driver, force=False):
> >      except ValueError as ex:
> >          sys.exit(ex)
> >
> > +    # check for IOMMU support
> > +    if not check_iommu():
> > +        if driver == "vfio-pci":
> > +            enable_noiommu_mode()
> > +
> >      for d in dev_list:
> >          bind_one(d, driver, force)
> >
> I like the idea of doing this from the script, but I would rather it not
> happen by default, since no-iommu reduces the security of the system. In
> the normal case, I think it would be best if the script printed an error
> message asking the user to enable iommu. We can also then add a flag to
> allow the user to explicitly ask for no-iommu mode and take the risk.
>
> /Bruce

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2022-03-10  4:08 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-03-08 12:49 [PATCH] usertools: add check for IOMMU support in dpdk-devbind Fidaullah Noonari
2022-03-08 12:56 ` Bruce Richardson
2022-03-10  4:08   ` Fidaullah Noonari

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.