On 6/18/2021 1:08 AM, Borislav Petkov wrote: > On Wed, Jun 02, 2021 at 09:04:14AM -0500, Brijesh Singh wrote: >> While launching the encrypted guests, the hypervisor may need to provide >> some additional information that will used during the guest boot. In the >> case of AMD SEV-SNP the information includes the address of the secrets >> and CPUID pages. The secrets page contains information such as a VM to >> PSP communication key and CPUID page contain PSP filtered CPUID values. >> >> When booting under the EFI based BIOS, the EFI configuration table >> contains an entry for the confidential computing blob. In order to support >> booting encrypted guests on non EFI VM, the hypervisor to pass these >> additional information to the kernel with different method. >> >> For this purpose expand the struct setup_header to hold the physical >> address of the confidential computing blob location. Being zero means it >> isn't passed. >> >> Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx> >> --- >> Documentation/x86/boot.rst | 27 +++++++++++++++++++++++++++ >> arch/x86/boot/header.S | 7 ++++++- >> arch/x86/include/uapi/asm/bootparam.h | 1 + >> 3 files changed, 34 insertions(+), 1 deletion(-) >> >> diff --git a/Documentation/x86/boot.rst b/Documentation/x86/boot.rst >> index fc844913dece..9b32805617bb 100644 >> --- a/Documentation/x86/boot.rst >> +++ b/Documentation/x86/boot.rst >> @@ -75,6 +75,8 @@ Protocol 2.14 BURNT BY INCORRECT COMMIT >> DO NOT USE!!! ASSUME SAME AS 2.13. >> >> Protocol 2.15 (Kernel 5.5) Added the kernel_info and kernel_info.setup_type_max. >> + >> +Protocol 2.16 (Kernel 5.14) Added the confidential computing blob address >> ============= ============================================================ >> >> .. note:: >> @@ -226,6 +228,7 @@ Offset/Size Proto Name Meaning >> 0260/4 2.10+ init_size Linear memory required during initialization >> 0264/4 2.11+ handover_offset Offset of handover entry point >> 0268/4 2.15+ kernel_info_offset Offset of the kernel_info >> +026C/4 2.16+ cc_blob_address Physical address of the confidential computing blob > > Why is this a separate thing instead of being passed as setup_data? > Don't have any strong reason to keep it separate, I can define a new type and use the setup_data to pass this information. -Brijesh
