Since commit 903cd0f315fe ("swiotlb: Use is_swiotlb_force_bounce for
swiotlb data bouncing") if code sets swiotlb_force it needs to do so
before the swiotlb is initialised. Otherwise
io_tlb_default_mem->force_bounce will not get set to true, and devices
that use (the default) swiotlb will not bounce despite switolb_force
having the value of SWIOTLB_FORCE.
Let us restore swiotlb functionality for PV by fulfilling this new
requirement.
This change addresses what turned out to be a fragility in
commit 64e1f0c531d1 ("s390/mm: force swiotlb for protected
virtualization"), which ain't exactly broken in its original context,
but could give us some more headache if people backport the broken
change and forget this fix.
Signed-off-by: Halil Pasic <[email protected]>
Tested-by: Christian Borntraeger <[email protected]>
Reviewed-by: Christian Borntraeger <[email protected]>
Fixes: 903cd0f315fe ("swiotlb: Use is_swiotlb_force_bounce for swiotlb data bouncing")
Fixes: 64e1f0c531d1 ("s390/mm: force swiotlb for protected virtualization")
Cc: [email protected] #5.3+
---
I'm aware that this fix does not really satisfy the formal requirements
for the stable process. But to avoid problems with backports we would
like this fix applied to 5.3+ stable kernels.
---
arch/s390/mm/init.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index d85bd7f5d8dc..1c8f8ccebfb7 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -186,9 +186,9 @@ static void pv_init(void)
return;
/* make sure bounce buffers are shared */
+ swiotlb_force = SWIOTLB_FORCE;
swiotlb_init(1);
swiotlb_update_mem_attributes();
- swiotlb_force = SWIOTLB_FORCE;
}
void __init mem_init(void)
base-commit: 90d856e71443a2fcacca8e7539bac44d9cb3f7ab
--
2.25.1
On Sat, Jul 24, 2021 at 01:17:46AM +0200, Halil Pasic wrote:
> Since commit 903cd0f315fe ("swiotlb: Use is_swiotlb_force_bounce for
> swiotlb data bouncing") if code sets swiotlb_force it needs to do so
> before the swiotlb is initialised. Otherwise
> io_tlb_default_mem->force_bounce will not get set to true, and devices
> that use (the default) swiotlb will not bounce despite switolb_force
> having the value of SWIOTLB_FORCE.
>
> Let us restore swiotlb functionality for PV by fulfilling this new
> requirement.
>
> This change addresses what turned out to be a fragility in
> commit 64e1f0c531d1 ("s390/mm: force swiotlb for protected
> virtualization"), which ain't exactly broken in its original context,
> but could give us some more headache if people backport the broken
> change and forget this fix.
>
> Signed-off-by: Halil Pasic <[email protected]>
> Tested-by: Christian Borntraeger <[email protected]>
> Reviewed-by: Christian Borntraeger <[email protected]>
> Fixes: 903cd0f315fe ("swiotlb: Use is_swiotlb_force_bounce for swiotlb data bouncing")
> Fixes: 64e1f0c531d1 ("s390/mm: force swiotlb for protected virtualization")
> Cc: [email protected] #5.3+
>
> ---
Picked it up and stuck it in linux-next with the other set of patches (Will's fixes).
On Fri, 23 Jul 2021 20:27:56 -0400
Konrad Rzeszutek Wilk <[email protected]> wrote:
> On Sat, Jul 24, 2021 at 01:17:46AM +0200, Halil Pasic wrote:
> > Since commit 903cd0f315fe ("swiotlb: Use is_swiotlb_force_bounce for
> > swiotlb data bouncing") if code sets swiotlb_force it needs to do so
> > before the swiotlb is initialised. Otherwise
> > io_tlb_default_mem->force_bounce will not get set to true, and devices
> > that use (the default) swiotlb will not bounce despite switolb_force
> > having the value of SWIOTLB_FORCE.
> >
> > Let us restore swiotlb functionality for PV by fulfilling this new
> > requirement.
> >
> > This change addresses what turned out to be a fragility in
> > commit 64e1f0c531d1 ("s390/mm: force swiotlb for protected
> > virtualization"), which ain't exactly broken in its original context,
> > but could give us some more headache if people backport the broken
> > change and forget this fix.
> >
> > Signed-off-by: Halil Pasic <[email protected]>
> > Tested-by: Christian Borntraeger <[email protected]>
> > Reviewed-by: Christian Borntraeger <[email protected]>
> > Fixes: 903cd0f315fe ("swiotlb: Use is_swiotlb_force_bounce for swiotlb data bouncing")
> > Fixes: 64e1f0c531d1 ("s390/mm: force swiotlb for protected virtualization")
> > Cc: [email protected] #5.3+
> >
> > ---
>
> Picked it up and stuck it in linux-next with the other set of patches (Will's fixes).
Thanks!
On 24.07.21 02:27, Konrad Rzeszutek Wilk wrote:
> On Sat, Jul 24, 2021 at 01:17:46AM +0200, Halil Pasic wrote:
>> Since commit 903cd0f315fe ("swiotlb: Use is_swiotlb_force_bounce for
>> swiotlb data bouncing") if code sets swiotlb_force it needs to do so
>> before the swiotlb is initialised. Otherwise
>> io_tlb_default_mem->force_bounce will not get set to true, and devices
>> that use (the default) swiotlb will not bounce despite switolb_force
>> having the value of SWIOTLB_FORCE.
>>
>> Let us restore swiotlb functionality for PV by fulfilling this new
>> requirement.
>>
>> This change addresses what turned out to be a fragility in
>> commit 64e1f0c531d1 ("s390/mm: force swiotlb for protected
>> virtualization"), which ain't exactly broken in its original context,
>> but could give us some more headache if people backport the broken
>> change and forget this fix.
>>
>> Signed-off-by: Halil Pasic <[email protected]>
>> Tested-by: Christian Borntraeger <[email protected]>
>> Reviewed-by: Christian Borntraeger <[email protected]>
>> Fixes: 903cd0f315fe ("swiotlb: Use is_swiotlb_force_bounce for swiotlb data bouncing")
>> Fixes: 64e1f0c531d1 ("s390/mm: force swiotlb for protected virtualization")
>> Cc: [email protected] #5.3+
>>
>> ---
>
> Picked it up and stuck it in linux-next with the other set of patches (Will's fixes).
Can you push out to kernel.org?
On 27.07.21 14:57, Will Deacon wrote:
> On Tue, Jul 27, 2021 at 02:54:14PM +0200, Christian Borntraeger wrote:
>>
>> On 24.07.21 02:27, Konrad Rzeszutek Wilk wrote:
>>> On Sat, Jul 24, 2021 at 01:17:46AM +0200, Halil Pasic wrote:
>>>> Since commit 903cd0f315fe ("swiotlb: Use is_swiotlb_force_bounce for
>>>> swiotlb data bouncing") if code sets swiotlb_force it needs to do so
>>>> before the swiotlb is initialised. Otherwise
>>>> io_tlb_default_mem->force_bounce will not get set to true, and devices
>>>> that use (the default) swiotlb will not bounce despite switolb_force
>>>> having the value of SWIOTLB_FORCE.
>>>>
>>>> Let us restore swiotlb functionality for PV by fulfilling this new
>>>> requirement.
>>>>
>>>> This change addresses what turned out to be a fragility in
>>>> commit 64e1f0c531d1 ("s390/mm: force swiotlb for protected
>>>> virtualization"), which ain't exactly broken in its original context,
>>>> but could give us some more headache if people backport the broken
>>>> change and forget this fix.
>>>>
>>>> Signed-off-by: Halil Pasic <[email protected]>
>>>> Tested-by: Christian Borntraeger <[email protected]>
>>>> Reviewed-by: Christian Borntraeger <[email protected]>
>>>> Fixes: 903cd0f315fe ("swiotlb: Use is_swiotlb_force_bounce for swiotlb data bouncing")
>>>> Fixes: 64e1f0c531d1 ("s390/mm: force swiotlb for protected virtualization")
>>>> Cc: [email protected] #5.3+
>>>>
>>>> ---
>>>
>>> Picked it up and stuck it in linux-next with the other set of patches (Will's fixes).
>>
>> Can you push out to kernel.org?
>
> It's pushed to the swiotlb tree:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb.git/log/?h=devel/for-linus-5.15
>
> Since none of the restricted DMA series is in mainline yet, I don't think
> it's needed anywhere else.
Ah right. It is not yet in todays next, so it might just be that yesterdays next pulled
from Konrad too early. Sorry for the noise.
On Tue, Jul 27, 2021 at 02:54:14PM +0200, Christian Borntraeger wrote:
>
> On 24.07.21 02:27, Konrad Rzeszutek Wilk wrote:
> > On Sat, Jul 24, 2021 at 01:17:46AM +0200, Halil Pasic wrote:
> > > Since commit 903cd0f315fe ("swiotlb: Use is_swiotlb_force_bounce for
> > > swiotlb data bouncing") if code sets swiotlb_force it needs to do so
> > > before the swiotlb is initialised. Otherwise
> > > io_tlb_default_mem->force_bounce will not get set to true, and devices
> > > that use (the default) swiotlb will not bounce despite switolb_force
> > > having the value of SWIOTLB_FORCE.
> > >
> > > Let us restore swiotlb functionality for PV by fulfilling this new
> > > requirement.
> > >
> > > This change addresses what turned out to be a fragility in
> > > commit 64e1f0c531d1 ("s390/mm: force swiotlb for protected
> > > virtualization"), which ain't exactly broken in its original context,
> > > but could give us some more headache if people backport the broken
> > > change and forget this fix.
> > >
> > > Signed-off-by: Halil Pasic <[email protected]>
> > > Tested-by: Christian Borntraeger <[email protected]>
> > > Reviewed-by: Christian Borntraeger <[email protected]>
> > > Fixes: 903cd0f315fe ("swiotlb: Use is_swiotlb_force_bounce for swiotlb data bouncing")
> > > Fixes: 64e1f0c531d1 ("s390/mm: force swiotlb for protected virtualization")
> > > Cc: [email protected] #5.3+
> > >
> > > ---
> >
> > Picked it up and stuck it in linux-next with the other set of patches (Will's fixes).
>
> Can you push out to kernel.org?
It's pushed to the swiotlb tree:
https://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb.git/log/?h=devel/for-linus-5.15
Since none of the restricted DMA series is in mainline yet, I don't think
it's needed anywhere else.
Will