linux/arch/x86/coco
Andi Kleen 32e72854fa x86/tdx: Port I/O: Add early boot support
TDX guests cannot do port I/O directly. The TDX module triggers a #VE
exception to let the guest kernel emulate port I/O by converting them
into TDCALLs to call the host.

But before IDT handlers are set up, port I/O cannot be emulated using
normal kernel #VE handlers. To support the #VE-based emulation during
this boot window, add a minimal early #VE handler support in early
exception handlers. This is similar to what AMD SEV does. This is
mainly to support earlyprintk's serial driver, as well as potentially
the VGA driver.

The early handler only supports I/O-related #VE exceptions. Unhandled or
failed exceptions will be handled via early_fixup_exceptions() (like
normal exception failures). At runtime I/O-related #VE exceptions (along
with other types) handled by virt_exception_kernel().

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/20220405232939.73860-19-kirill.shutemov@linux.intel.com
2022-04-07 08:27:52 -07:00
..
tdx x86/tdx: Port I/O: Add early boot support 2022-04-07 08:27:52 -07:00
core.c x86/tdx: Port I/O: Add runtime hypercalls 2022-04-07 08:27:52 -07:00
Makefile x86/tdx: Detect running as a TDX guest in early boot 2022-04-07 08:27:50 -07:00