tree a7add55ca321c68c3116de09762d567b9b7786f0
parent e311a92da18cbdd4972dab0cda88b1b8484b8fef
author Anshuman Khandual <khandual@linux.vnet.ibm.com> 1566267198 -0300
committer Michael Ellerman <mpe@ellerman.id.au> 1567122940 +1000

powerpc/pseries/svm: Use shared memory for LPPACA structures

LPPACA structures need to be shared with the host. Hence they need to be in
shared memory. Instead of allocating individual chunks of memory for a
given structure from memblock, a contiguous chunk of memory is allocated
and then converted into shared memory. Subsequent allocation requests will
come from the contiguous chunk which will be always shared memory for all
structures.

While we are able to use a kmem_cache constructor for the Debug Trace Log,
LPPACAs are allocated very early in the boot process (before SLUB is
available) so we need to use a simpler scheme here.

Introduce helper is_svm_platform() which uses the S bit of the MSR to tell
whether we're running as a secure guest.

Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190820021326.6884-9-bauerman@linux.ibm.com