diff options
| author | Michael Roth <michael.roth@amd.com> | 2022-02-09 12:10:01 -0600 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2022-04-06 13:02:21 +0200 |
| commit | ec1c66af3a30d45c2420da0974c01d3515dba26e (patch) | |
| tree | 34bb1217b891df832cff98f6b9988a6f276c734d /arch/x86/boot/compressed/mem_encrypt.S | |
| parent | 950d00558a920227b5703d1fcc4751cfe03853cd (diff) | |
x86/compressed/64: Detect/setup SEV/SME features earlier during boot
With upcoming SEV-SNP support, SEV-related features need to be
initialized earlier during boot, at the same point the initial #VC
handler is set up, so that the SEV-SNP CPUID table can be utilized
during the initial feature checks. Also, SEV-SNP feature detection
will rely on EFI helper functions to scan the EFI config table for the
Confidential Computing blob, and so would need to be implemented at
least partially in C.
Currently set_sev_encryption_mask() is used to initialize the
sev_status and sme_me_mask globals that advertise what SEV/SME features
are available in a guest. Rename it to sev_enable() to better reflect
that (SME is only enabled in the case of SEV guests in the
boot/compressed kernel), and move it to just after the stage1 #VC
handler is set up so that it can be used to initialize SEV-SNP as well
in future patches.
While at it, re-implement it as C code so that all SEV feature
detection can be better consolidated with upcoming SEV-SNP feature
detection, which will also be in C.
The 32-bit entry path remains unchanged, as it never relied on the
set_sev_encryption_mask() initialization to begin with.
[ bp: Massage commit message. ]
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-8-brijesh.singh@amd.com
Diffstat (limited to 'arch/x86/boot/compressed/mem_encrypt.S')
| -rw-r--r-- | arch/x86/boot/compressed/mem_encrypt.S | 36 |
1 files changed, 0 insertions, 36 deletions
diff --git a/arch/x86/boot/compressed/mem_encrypt.S b/arch/x86/boot/compressed/mem_encrypt.S index a63424d13627..a73e4d783cae 100644 --- a/arch/x86/boot/compressed/mem_encrypt.S +++ b/arch/x86/boot/compressed/mem_encrypt.S @@ -187,42 +187,6 @@ SYM_CODE_END(startup32_vc_handler) .code64 #include "../../kernel/sev_verify_cbit.S" -SYM_FUNC_START(set_sev_encryption_mask) -#ifdef CONFIG_AMD_MEM_ENCRYPT - push %rbp - push %rdx - - movq %rsp, %rbp /* Save current stack pointer */ - - call get_sev_encryption_bit /* Get the encryption bit position */ - testl %eax, %eax - jz .Lno_sev_mask - - bts %rax, sme_me_mask(%rip) /* Create the encryption mask */ - - /* - * Read MSR_AMD64_SEV again and store it to sev_status. Can't do this in - * get_sev_encryption_bit() because this function is 32-bit code and - * shared between 64-bit and 32-bit boot path. - */ - movl $MSR_AMD64_SEV, %ecx /* Read the SEV MSR */ - rdmsr - - /* Store MSR value in sev_status */ - shlq $32, %rdx - orq %rdx, %rax - movq %rax, sev_status(%rip) - -.Lno_sev_mask: - movq %rbp, %rsp /* Restore original stack pointer */ - - pop %rdx - pop %rbp -#endif - - xor %rax, %rax - RET -SYM_FUNC_END(set_sev_encryption_mask) .data |