On 11/26/2016 2:47 PM, Borislav Petkov wrote: > On Wed, Nov 09, 2016 at 06:38:38PM -0600, Tom Lendacky wrote: >> This patch adds the support to check if SME has been enabled and if the >> mem_encrypt=on command line option is set. If both of these conditions >> are true, then the encryption mask is set and the kernel is encrypted >> "in place." >> >> Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx> >> --- >> arch/x86/kernel/head_64.S | 1 + >> arch/x86/kernel/mem_encrypt_init.c | 60 +++++++++++++++++++++++++++++++++++- >> arch/x86/mm/mem_encrypt.c | 2 + >> 3 files changed, 62 insertions(+), 1 deletion(-) >> >> diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S >> index e8a7272..c225433 100644 >> --- a/arch/x86/kernel/head_64.S >> +++ b/arch/x86/kernel/head_64.S >> @@ -100,6 +100,7 @@ startup_64: >> * to include it in the page table fixups. >> */ >> push %rsi >> + movq %rsi, %rdi >> call sme_enable >> pop %rsi >> movq %rax, %r12 >> diff --git a/arch/x86/kernel/mem_encrypt_init.c b/arch/x86/kernel/mem_encrypt_init.c >> index 7bdd159..c94ceb8 100644 >> --- a/arch/x86/kernel/mem_encrypt_init.c >> +++ b/arch/x86/kernel/mem_encrypt_init.c >> @@ -16,9 +16,14 @@ >> #include <linux/mm.h> >> >> #include <asm/sections.h> >> +#include <asm/processor-flags.h> >> +#include <asm/msr.h> >> +#include <asm/cmdline.h> >> >> #ifdef CONFIG_AMD_MEM_ENCRYPT >> >> +static char sme_cmdline_arg[] __initdata = "mem_encrypt=on"; > > One more thing: just like we're adding an =on switch, we'd need an =off > switch in case something's wrong with the SME code. IOW, if a user > supplies "mem_encrypt=off", we do not encrypt. Well, we can document "off", but if the exact string "mem_encrypt=on" isn't specified on the command line then the encryption won't occur. The cmdline_find_option_bool() function looks for the exact string and isn't interpreting the value on the right side of the equal sign. So omitting mem_encrypt=on or using mem_encrypt=off is the same. Thanks, Tom > > Thanks. > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>