[linux-block.git] / arch / x86 / coco / tdx / tdx.c

// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2021-2022 Intel Corporation */

#undef pr_fmt
#define pr_fmt(fmt)     "tdx: " fmt

#include <linux/cpufeature.h>
#include <asm/coco.h>
#include <asm/tdx.h>

/* TDX module Call Leaf IDs */
#define TDX_GET_INFO			1

/*
 * Wrapper for standard use of __tdx_hypercall with no output aside from
 * return code.
 */
static inline u64 _tdx_hypercall(u64 fn, u64 r12, u64 r13, u64 r14, u64 r15)
{
	struct tdx_hypercall_args args = {
		.r10 = TDX_HYPERCALL_STANDARD,
		.r11 = fn,
		.r12 = r12,
		.r13 = r13,
		.r14 = r14,
		.r15 = r15,
	};

	return __tdx_hypercall(&args, 0);
}

/* Called from __tdx_hypercall() for unrecoverable failure */
void __tdx_hypercall_failed(void)
{
	panic("TDVMCALL failed. TDX module bug?");
}

/*
 * Used for TDX guests to make calls directly to the TD module.  This
 * should only be used for calls that have no legitimate reason to fail
 * or where the kernel can not survive the call failing.
 */
static inline void tdx_module_call(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9,
				   struct tdx_module_output *out)
{
	if (__tdx_module_call(fn, rcx, rdx, r8, r9, out))
		panic("TDCALL %lld failed (Buggy TDX module!)\n", fn);
}

static u64 get_cc_mask(void)
{
	struct tdx_module_output out;
	unsigned int gpa_width;

	/*
	 * TDINFO TDX module call is used to get the TD execution environment
	 * information like GPA width, number of available vcpus, debug mode
	 * information, etc. More details about the ABI can be found in TDX
	 * Guest-Host-Communication Interface (GHCI), section 2.4.2 TDCALL
	 * [TDG.VP.INFO].
	 *
	 * The GPA width that comes out of this call is critical. TDX guests
	 * can not meaningfully run without it.
	 */
	tdx_module_call(TDX_GET_INFO, 0, 0, 0, 0, &out);

	gpa_width = out.rcx & GENMASK(5, 0);

	/*
	 * The highest bit of a guest physical address is the "sharing" bit.
	 * Set it for shared pages and clear it for private pages.
	 */
	return BIT_ULL(gpa_width - 1);
}

void __init tdx_early_init(void)
{
	u64 cc_mask;
	u32 eax, sig[3];

	cpuid_count(TDX_CPUID_LEAF_ID, 0, &eax, &sig[0], &sig[2],  &sig[1]);

	if (memcmp(TDX_IDENT, sig, sizeof(sig)))
		return;

	setup_force_cpu_cap(X86_FEATURE_TDX_GUEST);

	cc_set_vendor(CC_VENDOR_INTEL);
	cc_mask = get_cc_mask();
	cc_set_mask(cc_mask);

	/*
	 * All bits above GPA width are reserved and kernel treats shared bit
	 * as flag, not as part of physical address.
	 *
	 * Adjust physical mask to only cover valid GPA bits.
	 */
	physical_mask &= cc_mask - 1;

	pr_info("Guest detected\n");
}
Commit	Line	Data
59bd54a8 KS	1	// SPDX-License-Identifier: GPL-2.0
	2	/* Copyright (C) 2021-2022 Intel Corporation */
	3
	4	#undef pr_fmt
	5	#define pr_fmt(fmt) "tdx: " fmt
	6
	7	#include <linux/cpufeature.h>
41394e33	8	#include <asm/coco.h>
59bd54a8 KS	9	#include <asm/tdx.h>
59bd54a8 KS	10
41394e33 KS	11	/* TDX module Call Leaf IDs */
	12	#define TDX_GET_INFO 1
	13
eb94f1b6 KS	14	/*
	15	* Wrapper for standard use of __tdx_hypercall with no output aside from
	16	* return code.
	17	*/
	18	static inline u64 _tdx_hypercall(u64 fn, u64 r12, u64 r13, u64 r14, u64 r15)
	19	{
	20	struct tdx_hypercall_args args = {
	21	.r10 = TDX_HYPERCALL_STANDARD,
	22	.r11 = fn,
	23	.r12 = r12,
	24	.r13 = r13,
	25	.r14 = r14,
	26	.r15 = r15,
	27	};
	28
	29	return __tdx_hypercall(&args, 0);
	30	}
	31
	32	/* Called from __tdx_hypercall() for unrecoverable failure */
	33	void __tdx_hypercall_failed(void)
	34	{
	35	panic("TDVMCALL failed. TDX module bug?");
	36	}
	37
41394e33 KS	38	/*
	39	* Used for TDX guests to make calls directly to the TD module. This
	40	* should only be used for calls that have no legitimate reason to fail
	41	* or where the kernel can not survive the call failing.
	42	*/
	43	static inline void tdx_module_call(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9,
	44	struct tdx_module_output *out)
	45	{
	46	if (__tdx_module_call(fn, rcx, rdx, r8, r9, out))
	47	panic("TDCALL %lld failed (Buggy TDX module!)\n", fn);
	48	}
	49
	50	static u64 get_cc_mask(void)
	51	{
	52	struct tdx_module_output out;
	53	unsigned int gpa_width;
	54
	55	/*
	56	* TDINFO TDX module call is used to get the TD execution environment
	57	* information like GPA width, number of available vcpus, debug mode
	58	* information, etc. More details about the ABI can be found in TDX
	59	* Guest-Host-Communication Interface (GHCI), section 2.4.2 TDCALL
	60	* [TDG.VP.INFO].
	61	*
	62	* The GPA width that comes out of this call is critical. TDX guests
	63	* can not meaningfully run without it.
	64	*/
	65	tdx_module_call(TDX_GET_INFO, 0, 0, 0, 0, &out);
	66
	67	gpa_width = out.rcx & GENMASK(5, 0);
	68
	69	/*
	70	* The highest bit of a guest physical address is the "sharing" bit.
	71	* Set it for shared pages and clear it for private pages.
	72	*/
	73	return BIT_ULL(gpa_width - 1);
	74	}
	75
59bd54a8 KS	76	void __init tdx_early_init(void)
59bd54a8 KS	77	{
41394e33	78	u64 cc_mask;
59bd54a8 KS	79	u32 eax, sig[3];
	80
	81	cpuid_count(TDX_CPUID_LEAF_ID, 0, &eax, &sig[0], &sig[2], &sig[1]);
	82
	83	if (memcmp(TDX_IDENT, sig, sizeof(sig)))
	84	return;
	85
	86	setup_force_cpu_cap(X86_FEATURE_TDX_GUEST);
	87
41394e33 KS	88	cc_set_vendor(CC_VENDOR_INTEL);
	89	cc_mask = get_cc_mask();
	90	cc_set_mask(cc_mask);
	91
65fab5bc KS	92	/*
	93	* All bits above GPA width are reserved and kernel treats shared bit
	94	* as flag, not as part of physical address.
	95	*
	96	* Adjust physical mask to only cover valid GPA bits.
	97	*/
	98	physical_mask &= cc_mask - 1;
	99
59bd54a8 KS	100	pr_info("Guest detected\n");
59bd54a8 KS	101	}