From: Halil Pasic pasic@linux.ibm.com
commit 93ebb6828723b8aef114415c4dc3518342f7dcad upstream.
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 pasic@linux.ibm.com Tested-by: Christian Borntraeger borntraeger@de.ibm.com Reviewed-by: Christian Borntraeger borntraeger@de.ibm.com Fixes: 903cd0f315fe ("swiotlb: Use is_swiotlb_force_bounce for swiotlb data bouncing") Fixes: 64e1f0c531d1 ("s390/mm: force swiotlb for protected virtualization") Cc: stable@vger.kernel.org #5.3+ Signed-off-by: Konrad Rzeszutek Wilk konrad@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/s390/mm/init.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- 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)