527a534c73
Secure Arbitration Mode (SEAM) is an extension of VMX architecture. It defines a new VMX root operation (SEAM VMX root) and a new VMX non-root operation (SEAM VMX non-root) which are both isolated from the legacy VMX operation where the host kernel runs. A CPU-attested software module (called 'TDX module') runs in SEAM VMX root to manage and protect VMs running in SEAM VMX non-root. SEAM VMX root is also used to host another CPU-attested software module (called 'P-SEAMLDR') to load and update the TDX module. Host kernel transits to either P-SEAMLDR or TDX module via the new SEAMCALL instruction, which is essentially a VMExit from VMX root mode to SEAM VMX root mode. SEAMCALLs are leaf functions defined by P-SEAMLDR and TDX module around the new SEAMCALL instruction. A guest kernel can also communicate with TDX module via TDCALL instruction. TDCALLs and SEAMCALLs use an ABI different from the x86-64 system-v ABI. RAX is used to carry both the SEAMCALL leaf function number (input) and the completion status (output). Additional GPRs (RCX, RDX, R8-R11) may be further used as both input and output operands in individual leaf. TDCALL and SEAMCALL share the same ABI and require the largely same code to pass down arguments and retrieve results. Define an assembly macro that can be used to implement C wrapper for both TDCALL and SEAMCALL. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20220405232939.73860-3-kirill.shutemov@linux.intel.com |
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