linux/arch/x86/boot/compressed/tdx.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef BOOT_COMPRESSED_TDX_H
#define BOOT_COMPRESSED_TDX_H

#include <linux/types.h>

#ifdef CONFIG_INTEL_TDX_GUEST
void early_tdx_detect(void);
#else
static inline void early_tdx_detect(void) { };
#endif

#endif /* BOOT_COMPRESSED_TDX_H */
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 2022-04-06 02:29:21 +03:00			`/* SPDX-License-Identifier: GPL-2.0 */`
			`#ifndef BOOT_COMPRESSED_TDX_H`
			`#define BOOT_COMPRESSED_TDX_H`

			`#include <linux/types.h>`

			`#ifdef CONFIG_INTEL_TDX_GUEST`
			`void early_tdx_detect(void);`
			`#else`
			`static inline void early_tdx_detect(void) { };`
			`#endif`

			`#endif /* BOOT_COMPRESSED_TDX_H */`