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author | Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> | 2022-04-06 02:29:21 +0300 |
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committer | Dave Hansen <dave.hansen@linux.intel.com> | 2022-04-07 18:27:51 +0300 |
commit | 4b05f81504bfcaab51083d3a271fada75e6b8904 (patch) | |
tree | fcb76e069a285a4bf3c11b78560754cd46aa931a /arch/x86/include/asm/shared | |
parent | 31d58c4e557d46fa7f8557714250fb6f89c941ae (diff) | |
download | linux-4b05f81504bfcaab51083d3a271fada75e6b8904.tar.xz |
x86/tdx: Detect TDX at early kernel decompression time
The early decompression code does port I/O for its console output. But,
handling the decompression-time port I/O demands a different approach
from normal runtime because the IDT required to support #VE based port
I/O emulation is not yet set up. Paravirtualizing I/O calls during
the decompression step is acceptable because the decompression code
doesn't have a lot of call sites to IO instruction.
To support port I/O in decompression code, TDX must be detected before
the decompression code might do port I/O. Detect whether the kernel runs
in a TDX guest.
Add an early_is_tdx_guest() interface to query the cached TDX guest
status in the decompression code.
TDX is detected with CPUID. Make cpuid_count() accessible outside
boot/cpuflags.c.
TDX detection in the main kernel is very similar. Move common bits
into <asm/shared/tdx.h>.
The actual port I/O paravirtualization will come later in the series.
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: Tony Luck <tony.luck@intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/20220405232939.73860-13-kirill.shutemov@linux.intel.com
Diffstat (limited to 'arch/x86/include/asm/shared')
-rw-r--r-- | arch/x86/include/asm/shared/tdx.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/x86/include/asm/shared/tdx.h b/arch/x86/include/asm/shared/tdx.h new file mode 100644 index 000000000000..8209ba9ffe1a --- /dev/null +++ b/arch/x86/include/asm/shared/tdx.h @@ -0,0 +1,8 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_X86_SHARED_TDX_H +#define _ASM_X86_SHARED_TDX_H + +#define TDX_CPUID_LEAF_ID 0x21 +#define TDX_IDENT "IntelTDX " + +#endif /* _ASM_X86_SHARED_TDX_H */ |