forked from Minki/linux
f39642d0db
Secondary CPU startup is currently performed with something called the "INIT/SIPI protocol". This protocol requires assistance from VMMs to boot guests. As should be a familiar story by now, that support can not be provded to TDX guests because TDX VMMs are not trusted by guests. To remedy this situation a new[1] "Multiprocessor Wakeup Structure" has been added to to an existing ACPI table (MADT). This structure provides the physical address of a "mailbox". A write to the mailbox then steers the secondary CPU to the boot code. Add ACPI MADT wake structure parsing support and wake support. Use this support to wake CPUs whenever it is present instead of INIT/SIPI. While this structure can theoretically be used on 32-bit kernels, there are no 32-bit TDX guest kernels. It has not been tested and can not practically *be* tested on 32-bit. Make it 64-bit only. 1. Details about the new structure can be found in ACPI v6.4, in the "Multiprocessor Wakeup Structure" section. Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@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: Andi Kleen <ak@linux.intel.com> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://lkml.kernel.org/r/20220405232939.73860-22-kirill.shutemov@linux.intel.com |
||
|---|---|---|
| .. | ||
| asm | ||
| uapi/asm | ||