| Message ID | CAG8fp8Te=oT1JJhTpOZvgWJrgcTq2DXan8UOVZ=KYCYNa8cKog@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | efi: bump efistub version from 1.1 to 3.0 for VZLinuxBootLoader compatibility | expand |
> > I'll queue this as a fix, but I'm going to tweak the comment (and the > > commit log) a bit, if you don't mind Thank you for rewriting my comments, but the new comments seem slightly incorrect: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=36e4fc57fc1619f462e669e939209c45763bc8f5 > efi: Bump stub image version for macOS HVF compatibility The commit is about Virtualization.framework, not about Hypervisor.framework (HVF). Virtualization.framework = high-level VMM, similar to QEMU (/usr/bin/qemu-system-*) Hypervisor.framework = low-level VMM, similar to kvm.ko > The macOS hypervisor framework includes a host-side VMM called VZLinuxBootLoader VZLinuxBootLoader is a part of Virtualization.framework, not Hypervisor.framework. Also, VZLinuxBootLoader is not a VMM; it is just an API for loading vmlinuz into Virtualization.framework. (similar to the `-kernel` and the `-initrd` flags of QEMU) > On x86, it incorporates a BIOS style loader that does not implement or expose EFI to the loaded kernel. AFAICS, it does not seem to use real mode BIOS. 2023年5月29日(月) 9:51 Akihiro Suda <suda.kyoto@gmail.com>: > > > > The next version will be 7 (0b111). > > > > How so? If this is going to be a monotonically increasing sequence > > after all, it is still not a bit mask, and this change defeats the > > purpose. > > Sorry, I forgot to append ", if it will retain compatibility with 0b11". > > > I'll queue this as a fix, but I'm going to tweak the comment (and the > > commit log) a bit, if you don't mind > > Thanks, please feel free to tweak that. > > > I'd appreciate it if you still report this as a bug with Apple, though. > > Reported via https://www.apple.com/feedback/macos.html > > > 2023年5月29日(月) 3:48 Ard Biesheuvel <ardb@kernel.org>: > > > > On Sun, 28 May 2023 at 09:59, Akihiro Suda <suda.kyoto@gmail.com> wrote: > > > > > > - LINUX_EFISTUB_MAJOR_VERSION is bumped from 1 (0b1) to 3 (0b11). > > > The value is now a bitfield. > > > > > > > OK > > > > > The next version will be 7 (0b111). > > > > How so? If this is going to be a monotonically increasing sequence > > after all, it is still not a bit mask, and this change defeats the > > purpose. > > > > > - LINUX_EFISTUB_MINOR_VERSION is pinned to 0x0, because Apple's > > > VZLinuxBootLoader [1] cannot boot a kernel with other minor version value [2], > > > even though it does not use UEFI. Tested with macOS 13.4 (x86_64). > > > > > > [1] https://developer.apple.com/documentation/virtualization/vzlinuxbootloader > > > [2] https://lore.kernel.org/linux-efi/CAG8fp8Teu4G9JuenQrqGndFt2Gy+V4YgJ=hN1xX7AD940YKf3A@mail.gmail.com/ > > > > > > Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217485 > > > Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp> > > > > I'll queue this as a fix, but I'm going to tweak the comment (and the > > commit log) a bit, if you don't mind > > > > I'd appreciate it if you still report this as a bug with Apple, though. > > > > Thanks, > > Ard. > > > > > --- > > > include/linux/pe.h | 20 ++++++++++++++++++-- > > > 1 file changed, 18 insertions(+), 2 deletions(-) > > > > > > diff --git a/include/linux/pe.h b/include/linux/pe.h > > > index 5e1e11540870..ee5ade19b7eb 100644 > > > --- a/include/linux/pe.h > > > +++ b/include/linux/pe.h > > > @@ -27,9 +27,25 @@ > > > * On x86, LoadImage() and StartImage() can be omitted if the EFI handover > > > * protocol is implemented, which can be inferred from the version, > > > * handover_offset and xloadflags fields in the bootparams structure. > > > + * > > > + * Linux EFI stub v1.1 unconditionally enabled initrd command line loader, > > > + * which was previously gated by CONFIG_EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER. > > > + * > > > + * Linux EFI stub v3.0 changed the major version to be a bitfield (0b11). > > > + * The rightmost bit means that it is compatible with v1.0 at least. > > > + * The second rightmost bit means that initrd command line loader is enabled. > > > + * So, there is no v2.0 (0b10), and the next version will be v7.0 (0b111). > > > + */ > > > +#define LINUX_EFISTUB_MAJOR_VERSION 0x3 > > > + > > > +/* > > > + * LINUX_EFISTUB_MINOR_VERSION is pinned to 0x0, because Apple's > > > + * VZLinuxBootLoader cannot boot a kernel with other minor version value, even > > > + * though it does not use UEFI. Tested with macOS 13.4 (x86_64). > > > + * > > > + * https://lore.kernel.org/linux-efi/CAG8fp8Teu4G9JuenQrqGndFt2Gy+V4YgJ=hN1xX7AD940YKf3A@mail.gmail.com/ > > > */ > > > -#define LINUX_EFISTUB_MAJOR_VERSION 0x1 > > > -#define LINUX_EFISTUB_MINOR_VERSION 0x1 > > > +#define LINUX_EFISTUB_MINOR_VERSION 0x0 > > > > > > /* > > > * LINUX_PE_MAGIC appears at offset 0x38 into the MS-DOS header of EFI bootable > > > -- > > > 2.39.2
On Fri, 2 Jun 2023 at 22:30, Akihiro Suda <suda.kyoto@gmail.com> wrote: > > > > I'll queue this as a fix, but I'm going to tweak the comment (and the > > > commit log) a bit, if you don't mind > > Thank you for rewriting my comments, but the new comments seem > slightly incorrect: > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=36e4fc57fc1619f462e669e939209c45763bc8f5 > > > efi: Bump stub image version for macOS HVF compatibility > > The commit is about Virtualization.framework, not about > Hypervisor.framework (HVF). > > Virtualization.framework = high-level VMM, similar to QEMU > (/usr/bin/qemu-system-*) > Hypervisor.framework = low-level VMM, similar to kvm.ko > > > The macOS hypervisor framework includes a host-side VMM called VZLinuxBootLoader > > VZLinuxBootLoader is a part of Virtualization.framework, not > Hypervisor.framework. > Also, VZLinuxBootLoader is not a VMM; it is just an API for loading > vmlinuz into Virtualization.framework. > (similar to the `-kernel` and the `-initrd` flags of QEMU) > Apologies for these mistakes. Unfortunately, this patch has been merged now so there is nothing we can do about it. > > On x86, it incorporates a BIOS style loader that does not implement or expose EFI to the loaded kernel. > > AFAICS, it does not seem to use real mode BIOS. > I never mentioned real mode, did I?
> > > On x86, it incorporates a BIOS style loader that does not implement or expose EFI to the loaded kernel. > > > > AFAICS, it does not seem to use real mode BIOS. > > > > I never mentioned real mode, did I? Sorry, I just misinterpreted "BIOS style loader". 2023年6月3日(土) 7:52 Ard Biesheuvel <ardb@kernel.org>: > > On Fri, 2 Jun 2023 at 22:30, Akihiro Suda <suda.kyoto@gmail.com> wrote: > > > > > > I'll queue this as a fix, but I'm going to tweak the comment (and the > > > > commit log) a bit, if you don't mind > > > > Thank you for rewriting my comments, but the new comments seem > > slightly incorrect: > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=36e4fc57fc1619f462e669e939209c45763bc8f5 > > > > > efi: Bump stub image version for macOS HVF compatibility > > > > The commit is about Virtualization.framework, not about > > Hypervisor.framework (HVF). > > > > Virtualization.framework = high-level VMM, similar to QEMU > > (/usr/bin/qemu-system-*) > > Hypervisor.framework = low-level VMM, similar to kvm.ko > > > > > The macOS hypervisor framework includes a host-side VMM called VZLinuxBootLoader > > > > VZLinuxBootLoader is a part of Virtualization.framework, not > > Hypervisor.framework. > > Also, VZLinuxBootLoader is not a VMM; it is just an API for loading > > vmlinuz into Virtualization.framework. > > (similar to the `-kernel` and the `-initrd` flags of QEMU) > > > > Apologies for these mistakes. Unfortunately, this patch has been > merged now so there is nothing we can do about it. > > > > On x86, it incorporates a BIOS style loader that does not implement or expose EFI to the loaded kernel. > > > > AFAICS, it does not seem to use real mode BIOS. > > > > I never mentioned real mode, did I?
diff --git a/include/linux/pe.h b/include/linux/pe.h index 5e1e11540870..ee5ade19b7eb 100644 --- a/include/linux/pe.h +++ b/include/linux/pe.h @@ -27,9 +27,25 @@ * On x86, LoadImage() and StartImage() can be omitted if the EFI handover * protocol is implemented, which can be inferred from the version, * handover_offset and xloadflags fields in the bootparams structure. + * + * Linux EFI stub v1.1 unconditionally enabled initrd command line loader, + * which was previously gated by CONFIG_EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER. + * + * Linux EFI stub v3.0 changed the major version to be a bitfield (0b11). + * The rightmost bit means that it is compatible with v1.0 at least. + * The second rightmost bit means that initrd command line loader is enabled. + * So, there is no v2.0 (0b10), and the next version will be v7.0 (0b111). + */ +#define LINUX_EFISTUB_MAJOR_VERSION 0x3 + +/* + * LINUX_EFISTUB_MINOR_VERSION is pinned to 0x0, because Apple's + * VZLinuxBootLoader cannot boot a kernel with other minor version value, even + * though it does not use UEFI. Tested with macOS 13.4 (x86_64). + * + * https://lore.kernel.org/linux-efi/CAG8fp8Teu4G9JuenQrqGndFt2Gy+V4YgJ=hN1xX7AD940YKf3A@mail.gmail.com/ */ -#define LINUX_EFISTUB_MAJOR_VERSION 0x1 -#define LINUX_EFISTUB_MINOR_VERSION 0x1 +#define LINUX_EFISTUB_MINOR_VERSION 0x0 /* * LINUX_PE_MAGIC appears at offset 0x38 into the MS-DOS header of EFI bootable
- LINUX_EFISTUB_MAJOR_VERSION is bumped from 1 (0b1) to 3 (0b11). The value is now a bitfield. The next version will be 7 (0b111). - LINUX_EFISTUB_MINOR_VERSION is pinned to 0x0, because Apple's VZLinuxBootLoader [1] cannot boot a kernel with other minor version value [2], even though it does not use UEFI. Tested with macOS 13.4 (x86_64). [1] https://developer.apple.com/documentation/virtualization/vzlinuxbootloader [2] https://lore.kernel.org/linux-efi/CAG8fp8Teu4G9JuenQrqGndFt2Gy+V4YgJ=hN1xX7AD940YKf3A@mail.gmail.com/ Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217485 Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp> --- include/linux/pe.h | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-)