On Sun, Jul 10, 2016 at 07:40:53PM +0800, Wan Zongshun wrote: > Do you mean we need enable the V and TV bits to DTE entry after all > DTEs tables were initialized completely? Yes, this is what my patch does and what fixes the bug that was reported on machines which have unity-mapping entries. > I checked this function 'init_device_table_dma', and find it just set > V and TV bit, to set translation info valid and DTE bits127:1 valid. Right, if no other bits are set this blocks all DMA from the gives device-id. > So I just think all things it should to do are to allow DMA access, > GPA-to-SPA translation should be active, why you add function > comments below is to not allow DMA access and suppress all page > faults? > > /* > * Init the device table to not allow DMA access for devices and > * suppress all page faults > */ Yeah, that comment needs to be updated. Not all DMA is blocked and page-faults are not suppressed at all. Thanks for noticing. Joerg -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html