Messages in this thread | | | Date | Thu, 6 Jun 2013 14:14:39 +0100 | From | Matt Fleming <> | Subject | Re: [PATCH 4/4] x86, efi: Map runtime services 1:1 |
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On Sun, 02 Jun, at 02:56:10PM, Borislav Petkov wrote: > From: Borislav Petkov <bp@suse.de> > > Due to the braindead design of EFI, we cannot map runtime services more > than once for the duration of a booted system. Thus, if we want to use > EFI runtime services in a kexec'ed kernel, maybe the only possible and > sensible approach would be to map them 1:1 so that when the kexec kernel > loads, it can simply call those addresses without the need for remapping > (which doesn't work anyway). > > Furthermore, this mapping approach could be of help with b0rked EFI > implementations for a different set of reasons. > > This implementation is 64-bit only for now and it boots fine in kvm with > OVMF BIOS. > > Signed-off-by: Borislav Petkov <bp@suse.de> > --- > arch/x86/include/asm/efi.h | 2 + > arch/x86/platform/efi/efi.c | 161 +++++++++++++++++++++++++++++------- > arch/x86/platform/efi/efi_stub_64.S | 48 +++++++++++ > 3 files changed, 180 insertions(+), 31 deletions(-)
This patch makes my TunnelMountain machine spin in handle_pte_fault() when triggering one of the "firmware makes references to physical addresses" code paths.
I'll try and dig into this tomorrow to figure out what's going on.
-- Matt Fleming, Intel Open Source Technology Center
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