The VT-d specification (section 7.6) requires that the value in the Private Data field of a Page Group Response Descriptor must match the value in the Private Data field of the respective Page Request Descriptor.
The private data field of a page group response descriptor is set then immediately cleared in prq_event_thread(). This breaks the rule defined by the VT-d specification. Fix it by moving clearing code up. Fixes: 5b438f4ba315d ("iommu/vt-d: Support page request in scalable mode") Cc: Jacob Pan <jacob.jun....@linux.intel.com> Reviewed-by: Liu Yi L <yi.l....@intel.com> Signed-off-by: Lu Baolu <baolu...@linux.intel.com> --- drivers/iommu/intel/svm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) Log: v1->v2: - v1: https://lore.kernel.org/linux-iommu/20210309004641.3809653-1-baolu...@linux.intel.com/ - Refine the commit title to make the affected field clear. - Refine the commit message to declare why the change matters. diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c index 677d7f6b43bb..5d590d63ab52 100644 --- a/drivers/iommu/intel/svm.c +++ b/drivers/iommu/intel/svm.c @@ -1034,12 +1034,12 @@ static irqreturn_t prq_event_thread(int irq, void *d) QI_PGRP_RESP_TYPE; resp.qw1 = QI_PGRP_IDX(req->prg_index) | QI_PGRP_LPIG(req->lpig); + resp.qw2 = 0; + resp.qw3 = 0; if (req->priv_data_present) memcpy(&resp.qw2, req->priv_data, sizeof(req->priv_data)); - resp.qw2 = 0; - resp.qw3 = 0; qi_submit_sync(iommu, &resp, 1, 0); } prq_advance: -- 2.25.1