On Tue, 22 Nov 2022 at 22:37, Ard Biesheuvel <ardb@xxxxxxxxxx> wrote: > > On Tue, 22 Nov 2022 at 21:48, Tom Lendacky <thomas.lendacky@xxxxxxx> wrote: > > > > On 11/22/22 10:10, Ard Biesheuvel wrote: > > > After doing some cleanup work on the EFI code in head_64.S, the mixed > > > mode code in particular, I noticed that the memory encryption pieces > > > could use some attention as well, so I cleaned that up too. > > > > > > Changes since v2: > > > - add some clarifying comments to the EFI mixed mode changes > > > - include patch to make the EFI handover protocol optional that was sent > > > out separately before > > > - rebase onto tip/master > > > > > > Changes since v1: > > > - at Boris's request, split the patches into smaller ones that are > > > easier to review > > > > > > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > > > Cc: Ingo Molnar <mingo@xxxxxxxxxx> > > > Cc: Borislav Petkov <bp@xxxxxxxxx> > > > Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> > > > Cc: Michael Roth <michael.roth@xxxxxxx> > > > > This causes an SEV guest to blow up on boot in the early boot code. It > > looks like the stack pointer is not valid and it triple faults on a pushq > > instruction (pushq $__KERNEL_CS in arch/x86/boot/compressed/head_64.S of > > startup_64). > > > > Thanks for the report. > > So the mystery here (at least to me) is that all the changes are to > the 32-bit code, and startup_64 reloads the stack pointer from the > symbol > > Does your config have CONFIG_EFI_MIXED enabled? > > Can I reproduce this fully emulated with QEMU? Or do I need a SEV host? > Also, mind giving this a quick spin? diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c index cb5f0befee57..1af11d34bc6c 100644 --- a/drivers/firmware/efi/libstub/x86-stub.c +++ b/drivers/firmware/efi/libstub/x86-stub.c @@ -23,7 +23,7 @@ const efi_system_table_t *efi_system_table; const efi_dxe_services_table_t *efi_dxe_table; -u32 image_offset; +u32 __section(".data") image_offset; static efi_loaded_image_t *image = NULL; static efi_status_t Thanks, Ard.