On Fri, Nov 20, 2020 at 3:30 PM Ard Biesheuvel <ardb@xxxxxxxxxx> wrote: > > On Fri, 20 Nov 2020 at 21:19, Nick Desaulniers <ndesaulniers@xxxxxxxxxx> wrote: > > > > On Fri, Nov 20, 2020 at 2:30 AM Ard Biesheuvel <ardb@xxxxxxxxxx> wrote: > > > > > > On Thu, 19 Nov 2020 at 00:42, Nick Desaulniers <ndesaulniers@xxxxxxxxxx> wrote: > > > > > > > > Thanks for continuing to drive this series Sami. For the series, > > > > > > > > Tested-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> > > > > > > > > I did virtualized boot tests with the series applied to aarch64 > > > > defconfig without CONFIG_LTO, with CONFIG_LTO_CLANG, and a third time > > > > with CONFIG_THINLTO. If you make changes to the series in follow ups, > > > > please drop my tested by tag from the modified patches and I'll help > > > > re-test. Some minor feedback on the Kconfig change, but I'll post it > > > > off of that patch. > > > > > > > > > > When you say 'virtualized" do you mean QEMU on x86? Or actual > > > virtualization on an AArch64 KVM host? > > > > aarch64 guest on x86_64 host. If you have additional configurations > > that are important to you, additional testing help would be > > appreciated. > > > > Could you run this on an actual phone? Or does Android already ship > with this stuff? By `this`, if you mean "the LTO series", it has been shipping on Android phones for years now, I think it's even required in the latest release. If you mean "the LTO series + mainline" on a phone, well there's the android-mainline of https://android.googlesource.com/kernel/common/, in which this series was recently removed in order to facilitate rebasing Android's patches on ToT-mainline until getting the series landed upstream. Bit of a chicken and the egg problem there. If you mean "the LTO series + mainline + KVM" on a phone; I don't know the precise state of aarch64 KVM and Android (Will or Marc would know). We did experiment recently with RockPI's for aach64 KVM, IIRC; I think Android is tricky as it still requires A64+A32/T32 chipsets, Alistair would know more. Might be interesting to boot a virtualized (or paravirtualized?) guest built with LTO in a host built with LTO for sure, but I don't know if we have tried that yet (I think we did try LTO guests of android kernels, but I think they were on the stock RockPI host BSP image IIRC). > > > The distinction is important here, given the potential impact of LTO > > > on things that QEMU simply does not model when it runs in TCG mode on > > > a foreign host architecture. -- Thanks, ~Nick Desaulniers
