Re: [GIT PULL] EFI urgent fixes

From: Ingo Molnar
Date: Wed Feb 18 2015 - 08:44:09 EST



* Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx> wrote:

> Folks, please pull the following fixes. The revert addresses a
> regression that Ard hit when booting Qemu and Xen, and the other patch
> ensures that we don't triple fault when receiving an NMI or MCE during
> an EFI mixed mode call, which may happen, for instance, when running
> perf.
>
> The pull is against tip/x86/efi because tip/x86/urgent doesn't contain
> commit d1a8d66b9177 ("efi/libstub: Call get_memory_map() to obtain map
> and desc sizes") needed for the revert.
>
> If you'd prefer for me to resend this after the merge window closes,
> just let me know.
>
> The following changes since commit 3c01b74e818a7a3b2ee9b0d584cca0bc154a031c:
>
> Merge tag 'efi-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into x86/efi (2015-01-29 19:16:40 +0100)
>
> are available in the git repository at:
>
>
> git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi.git tags/efi-urgent
>
> for you to fetch changes up to 43a9f69692b232d1c64c913a27507eb14a1c47fd:
>
> Revert "efi/libstub: Call get_memory_map() to obtain map and desc sizes" (2015-02-18 11:38:13 +0000)
>
> ----------------------------------------------------------------
> * Leave a valid 64-bit IDT installed during runtime EFI mixed mode
> calls to avoid triple faults if an NMI/MCE is received.
>
> * Revert Ard's change to the libstub get_memory_map() that went into
> the v3.20 merge window because it causes boot regressions on Qemu and
> Xen.
>
> ----------------------------------------------------------------
> Matt Fleming (2):
> x86/efi: Avoid triple faults during EFI mixed mode calls
> Revert "efi/libstub: Call get_memory_map() to obtain map and desc sizes"
>
> arch/x86/boot/compressed/Makefile | 1 +
> arch/x86/boot/compressed/efi_stub_64.S | 25 ----
> arch/x86/boot/compressed/efi_thunk_64.S | 196 +++++++++++++++++++++++++
> arch/x86/platform/efi/efi_stub_64.S | 161 --------------------
> arch/x86/platform/efi/efi_thunk_64.S | 121 ++++++++++++---
> drivers/firmware/efi/libstub/efi-stub-helper.c | 16 +-
> 6 files changed, 307 insertions(+), 213 deletions(-)
> create mode 100644 arch/x86/boot/compressed/efi_thunk_64.S

Pulled, thanks Matt!

Btw., I find the revert a bit sad: in most cases breaking
virtualized environments isn't a regression really, it's
_them_ who couple to the kernel in an incestuous way that
causes the problem: fixes should come from them ...

Thanks,

Ingo
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