The functions are needed to map the GHCB for SEV-ES guests. The GHCB
is used for communication with the hypervisor, so its content must not
be encrypted. After the GHCB is not needed anymore it must be mapped
encrypted again so that the running kernel image can safely re-use the
memory.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-23-joro@8bytes.org
Call set_sev_encryption_mask() while still on the stage 1 #VC-handler
because the stage 2 handler needs the kernel's own page tables to be
set up, to which calling set_sev_encryption_mask() is a prerequisite.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-21-joro@8bytes.org
Changing the function to take start and end as parameters instead of
start and size simplifies the callers which don't need to calculate the
size if they already have start and end.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20200907131613.12703-19-joro@8bytes.org
With the page-fault handler in place, he identity mapping can be built
on-demand. So remove the code which manually creates the mappings and
unexport/remove the functions used for it.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20200907131613.12703-18-joro@8bytes.org
When booted through startup_64(), the kernel keeps running on the EFI
page table until the KASLR code sets up its own page table. Without
KASLR, the pre-decompression boot code never switches off the EFI page
table. Change that by unconditionally switching to a kernel-controlled
page table after relocation.
This makes sure the kernel can make changes to the mapping when
necessary, for example map pages unencrypted in SEV and SEV-ES guests.
Also, remove the debug_putstr() calls in initialize_identity_maps()
because the function now runs before console_init() is called.
[ bp: Massage commit message. ]
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20200907131613.12703-17-joro@8bytes.org
Install a page-fault handler to add an identity mapping to addresses
not yet mapped. Also do some checking whether the error code is sane.
This makes non SEV-ES machines use the exception handling
infrastructure in the pre-decompressions boot code too, making it less
likely to break in the future.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20200907131613.12703-16-joro@8bytes.org
The file contains only code related to identity-mapped page tables.
Rename the file and compile it always in.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20200907131613.12703-15-joro@8bytes.org
