On Thu, Feb 16, 2017 at 09:43:48AM -0600, Tom Lendacky wrote:
Add to the early_memremap support to be able to specify encrypted and
Please append "()" to function names in your commit messages text.
decrypted mappings with and without write-protection. The use of
write-protection is necessary when encrypting data "in place". The
write-protect attribute is considered cacheable for loads, but not
stores. This implies that the hardware will never give the core a
dirty line with this memtype.
By "hardware will never give" you mean that WP writes won't land dirty
in the cache but will go out to mem and when some other core needs them,
they will have to come from memory?
Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
arch/x86/Kconfig | 4 +++
arch/x86/include/asm/fixmap.h | 13 ++++++++++
arch/x86/include/asm/pgtable_types.h | 8 ++++++
arch/x86/mm/ioremap.c | 44 ++++++++++++++++++++++++++++++++++
include/asm-generic/early_ioremap.h | 2 ++
mm/early_ioremap.c | 10 ++++++++
6 files changed, 81 insertions(+)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index a3b8c71..581eae4 100644
@@ -1417,6 +1417,10 @@ config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
If set to N, then the encryption of system memory can be
activated with the mem_encrypt=on command line option.
+ def_bool y
+ depends on AMD_MEM_ENCRYPT
Why do we need this?
IOW, all those helpers below will end up being defined unconditionally,
in practice. Think distro kernels. Then saving the couple of bytes is
not really worth the overhead.