On Sun, Oct 31, 2021 at 9:14 AM Marc Orr <marcorr@xxxxxxxxxx> wrote: > > On Sun, Oct 31, 2021 at 12:28 AM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > > > > On 31/10/21 06:56, Zixuan Wang wrote: > > > Hello, > > > > > > This patch series refactors the x86_64 UEFI set up process and fixes the > > > `run-tests.sh` script to run under UEFI. The patches are organized as > > > three parts. > > > > > > The first part (patches 1-2) refactors the x86_64 UEFI set up process. > > > The previous UEFI setup calls arch-specific setup functions twice and > > > generates arch-specific data structure. As Andrew suggested [1], we > > > refactor this process to make only one call to the arch-specific > > > function and generate arch-neutral data structures. This simplifies the > > > set up process and makes it easier to develop UEFI support for other > > > architectures. > > > > > > The second part (patch 3) converts several x86 test cases to > > > Position-Independent Code (PIC) to run under UEFI. This patch is ported > > > from the initial UEFI support patchset [2] with fixes to the 32-bit > > > compilation. > > > > > > The third part (patches 4-7) fixes the UEFI runner scripts. Patch 4 sets > > > UEFI OVMF image as readonly. Patch 5 fixes test cases' return code under > > > UEFI, enabling Patch 6-7 to fix the `run-tests.sh` script under UEFI. > > > > > > This patch set is based on the `uefi` branch. > > > > Thank you, for patches 1-6 I have squashed the patches when applicable > > (1, 4, 5, 6) and queued the others (2 and 3). > > > > I did not queue patch 7 yet, it seems okay but I want to understand > > better the changes it needs in the harness and what is missing. I'll > > take a look during the week. > > SGTM, thank you! Zixuan and I discussed a few things that are missing: > > 1. Test cases that take the `-append` arg are currently marked `SKIP`. > Two issues need to be resolved here. First, we're not using QEMU's > `-kernel` flag for EFI test cases [1]. And the `-append` flag does not > work without the `-kernel` flag. I don't understand the details on why > we don't use the `-kernel` flag myself. Maybe Zixuan can elaborate. > Second, assuming we fix the first issue, then we need to enlighten the > KVM-Unit-Tests under UEFI to parse kernel command line arguments and > pass them down to the test cases via `argv`. Zixuan pointed out to me > that there is some prior work from Drew [2] that we should be able to > follow to make this work. So I'm hoping that Zixuan and I can work > together on solving these issues to get the argument passing working > next. Thank you for the detailed summary! Current kvm-unit-tests pass an EFI binary as part of a disk image, instead of using the `-kernel` argument. I just tested the `-kernel` argument and it seems to work with EFI binaries, and more importantly, it's really fast (bypassing the default 5-second user input waiting). I will update the `x86/efi/run` to use `-kernel` argument to pass the EFI binaries. Since `-kernel` is working, I can start to investigate how to use `-append` to pass arguments. If that doesn't work well, an alternative approach could be: 1. (host) create a file `args.txt` in the disk image, which contains all the arguments needed 2. (guest) call UEFI filesystem interface to read this `args.txt` from the disk image, parse it and pass the arguments to `main()` > 2. We need a way to annotate test cases in `x86/unittests.cfg` as > known to work under SEV. I'm thinking of doing this via new (very > broad) test groups in `unittests.cfg`. I _think_ SEV is the primary > scenario we care about. However, folks may care about running the test > cases under UEFI outside of SEV. For example, last time I checked, > emulator runs OK under UEFI minus SEV-ES but fails under SEV-ES. And > similarly, while most test cases work under UEFI minus SEV, there are > a few that do mis-behave -- and it probably makes sense to document > this (e.g., via annotations in `unittests.cfg`). Also, there are many > variations of SEV (SEV, SEV-ES, SEV-SNP)... And hopefully some of this > will eventually be applicable to TDX as well. So many testgroups is > not a good solution. I'm not sure. Adding an `efi` group seems helpful. E.g., the current `x86/smap.c` does not work under UEFI; but the `run-tests.sh` still tries to run this test case, even if this test case is not compiled. > 3. Multi-CPU needs to be made to work under UEFI. For now, patch #7 > forces all EFI test cases to run with 1 vCPU. I chatted with Brijesh, > and he mentioned that Varad would like to work on this. However, if > anything here changes, please let me know, because we can work on this > as well. But for now, I'm not planning to work on it so we can avoid > duplicating work. > 4. UEFI runs a lot slower than SEABIOS. It doesn't help that the test > harness launches QEMU more than once for each test case (i.e., it runs > the `_NO_FILE_4Uhere_` scenario to check QEMU arguments). I'm not sure > how much of an issue this is in practice. Depending on the answer, I > know Zixuan had some ideas on how to speed this up in the current test > harness. Or maybe we can explore an alternative to the > `_NO_FILE_4Uhere_` approach instead. As the `-kernel` argument now works with the EFI binaries and is significantly faster, this should not be an issue anymore. We just need to update the runner scripts to use `-kernel` argument. > Zixuan: Please add/correct anything as needed! > > [1] https://gitlab.com/kvm-unit-tests/kvm-unit-tests/-/blob/uefi/x86/run#L42-44 > [2] https://github.com/rhdrjones/kvm-unit-tests/blob/target-efi/scripts/mkefi.sh > > Thanks, > Marc Best regards, Zixuan
