Hi Tony, I love your patch! Perhaps something to improve: [auto build test WARNING on s390/features] [also build test WARNING on mst-vhost/linux-next linus/master v5.19-rc5 next-20220704] [cannot apply to kvms390/next] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/intel-lab-lkp/linux/commits/Tony-Krowiak/s390-vfio-ap-dynamic-configuration-support/20220621-235654 base: https://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git features reproduce: make htmldocs If you fix the issue, kindly add following tag where applicable Reported-by: kernel test robot <lkp@xxxxxxxxx> All warnings (new ones prefixed by >>): >> Documentation/s390/vfio-ap.rst:684: WARNING: Inline strong start-string without end-string. >> Documentation/s390/vfio-ap.rst:684: WARNING: Inline emphasis start-string without end-string. >> Documentation/s390/vfio-ap.rst:943: WARNING: Title underline too short. >> Documentation/s390/vfio-ap.rst:998: WARNING: Definition list ends without a blank line; unexpected unindent. vim +684 Documentation/s390/vfio-ap.rst 538 539 1. Install the vfio_ap module on the linux host. The dependency chain for the 540 vfio_ap module is: 541 * iommu 542 * s390 543 * zcrypt 544 * vfio 545 * vfio_mdev 546 * vfio_mdev_device 547 * KVM 548 549 To build the vfio_ap module, the kernel build must be configured with the 550 following Kconfig elements selected: 551 * IOMMU_SUPPORT 552 * S390 553 * ZCRYPT 554 * S390_AP_IOMMU 555 * VFIO 556 * VFIO_MDEV 557 * KVM 558 559 If using make menuconfig select the following to build the vfio_ap module:: 560 561 -> Device Drivers 562 -> IOMMU Hardware Support 563 select S390 AP IOMMU Support 564 -> VFIO Non-Privileged userspace driver framework 565 -> Mediated device driver frramework 566 -> VFIO driver for Mediated devices 567 -> I/O subsystem 568 -> VFIO support for AP devices 569 570 2. Secure the AP queues to be used by the three guests so that the host can not 571 access them. To secure them, there are two sysfs files that specify 572 bitmasks marking a subset of the APQN range as usable only by the default AP 573 queue device drivers. All remaining APQNs are available for use by 574 any other device driver. The vfio_ap device driver is currently the only 575 non-default device driver. The location of the sysfs files containing the 576 masks are:: 577 578 /sys/bus/ap/apmask 579 /sys/bus/ap/aqmask 580 581 The 'apmask' is a 256-bit mask that identifies a set of AP adapter IDs 582 (APID). Each bit in the mask, from left to right, corresponds to an APID from 583 0-255. If a bit is set, the APID belongs to the subset of APQNs marked as 584 available only to the default AP queue device drivers. 585 586 The 'aqmask' is a 256-bit mask that identifies a set of AP queue indexes 587 (APQI). Each bit in the mask, from left to right, corresponds to an APQI from 588 0-255. If a bit is set, the APQI belongs to the subset of APQNs marked as 589 available only to the default AP queue device drivers. 590 591 The Cartesian product of the APIDs corresponding to the bits set in the 592 apmask and the APQIs corresponding to the bits set in the aqmask comprise 593 the subset of APQNs that can be used only by the host default device drivers. 594 All other APQNs are available to the non-default device drivers such as the 595 vfio_ap driver. 596 597 Take, for example, the following masks:: 598 599 apmask: 600 0x7d00000000000000000000000000000000000000000000000000000000000000 601 602 aqmask: 603 0x8000000000000000000000000000000000000000000000000000000000000000 604 605 The masks indicate: 606 607 * Adapters 1, 2, 3, 4, 5, and 7 are available for use by the host default 608 device drivers. 609 610 * Domain 0 is available for use by the host default device drivers 611 612 * The subset of APQNs available for use only by the default host device 613 drivers are: 614 615 (1,0), (2,0), (3,0), (4.0), (5,0) and (7,0) 616 617 * All other APQNs are available for use by the non-default device drivers. 618 619 The APQN of each AP queue device assigned to the linux host is checked by the 620 AP bus against the set of APQNs derived from the Cartesian product of APIDs 621 and APQIs marked as available to the default AP queue device drivers. If a 622 match is detected, only the default AP queue device drivers will be probed; 623 otherwise, the vfio_ap device driver will be probed. 624 625 By default, the two masks are set to reserve all APQNs for use by the default 626 AP queue device drivers. There are two ways the default masks can be changed: 627 628 1. The sysfs mask files can be edited by echoing a string into the 629 respective sysfs mask file in one of two formats: 630 631 * An absolute hex string starting with 0x - like "0x12345678" - sets 632 the mask. If the given string is shorter than the mask, it is padded 633 with 0s on the right; for example, specifying a mask value of 0x41 is 634 the same as specifying:: 635 636 0x4100000000000000000000000000000000000000000000000000000000000000 637 638 Keep in mind that the mask reads from left to right, so the mask 639 above identifies device numbers 1 and 7 (01000001). 640 641 If the string is longer than the mask, the operation is terminated with 642 an error (EINVAL). 643 644 * Individual bits in the mask can be switched on and off by specifying 645 each bit number to be switched in a comma separated list. Each bit 646 number string must be prepended with a ('+') or minus ('-') to indicate 647 the corresponding bit is to be switched on ('+') or off ('-'). Some 648 valid values are: 649 650 - "+0" switches bit 0 on 651 - "-13" switches bit 13 off 652 - "+0x41" switches bit 65 on 653 - "-0xff" switches bit 255 off 654 655 The following example: 656 657 +0,-6,+0x47,-0xf0 658 659 Switches bits 0 and 71 (0x47) on 660 661 Switches bits 6 and 240 (0xf0) off 662 663 Note that the bits not specified in the list remain as they were before 664 the operation. 665 666 2. The masks can also be changed at boot time via parameters on the kernel 667 command line like this: 668 669 ap.apmask=0xffff ap.aqmask=0x40 670 671 This would create the following masks:: 672 673 apmask: 674 0xffff000000000000000000000000000000000000000000000000000000000000 675 676 aqmask: 677 0x4000000000000000000000000000000000000000000000000000000000000000 678 679 Resulting in these two pools:: 680 681 default drivers pool: adapter 0-15, domain 1 682 alternate drivers pool: adapter 16-255, domains 0, 2-255 683 > 684 Note ***: 685 Changing a mask such that one or more APQNs will be taken from a vfio_ap 686 mediated device (see below) will fail with an error (EBUSY). A message 687 is logged to the kernel ring buffer which can be viewed with the 'dmesg' 688 command. The output identifies each APQN flagged as 'in use' and identifies 689 the vfio_ap mediated device to which it is assigned; for example: 690 691 Userspace may not re-assign queue 05.0054 already assigned to 62177883-f1bb-47f0-914d-32a22e3a8804 692 Userspace may not re-assign queue 04.0054 already assigned to cef03c3c-903d-4ecc-9a83-40694cb8aee4 693 -- 0-DAY CI Kernel Test Service https://01.org/lkp
