1 #include <asm/tdx.h>
2 #include <asm/pgtable.h>
3
4 static unsigned long try_accept_one(phys_addr_t start, unsigned long len,
5 enum pg_level pg_level)
6 {
7 unsigned long accept_size = page_level_size(pg_level);
8 struct tdx_module_args args = {};
9 u8 page_size;
10
11 if (!IS_ALIGNED(start, accept_size))
12 return 0;
13
14 if (len < accept_size)
15 return 0;
16
17 /*
18 * Pass the page physical address to the TDX module to accept the
19 * pending, private page.
20 *
21 * Bits 2:0 of RCX encode page size: 0 - 4K, 1 - 2M, 2 - 1G.
22 */
23 switch (pg_level) {
24 case PG_LEVEL_4K:
25 page_size = TDX_PS_4K;
26 break;
27 case PG_LEVEL_2M:
28 page_size = TDX_PS_2M;
29 break;
30 case PG_LEVEL_1G:
31 page_size = TDX_PS_1G;
32 break;
33 default:
34 return 0;
35 }
36
37 args.rcx = start | page_size;
38 if (__tdcall(TDG_MEM_PAGE_ACCEPT, &args))
39 return 0;
40
41 return accept_size;
42 }
43
44 bool tdx_accept_memory(phys_addr_t start, phys_addr_t end)
45 {
46 /*
47 * For shared->private conversion, accept the page using
48 * TDG_MEM_PAGE_ACCEPT TDX module call.
49 */
50 while (start < end) {
51 unsigned long len = end - start;
52 unsigned long accept_size;
53
54 /*
55 * Try larger accepts first. It gives chance to VMM to keep
56 * 1G/2M Secure EPT entries where possible and speeds up
57 * process by cutting number of hypercalls (if successful).
58 */
59
60 accept_size = try_accept_one(start, len, PG_LEVEL_1G);
61 if (!accept_size)
62 accept_size = try_accept_one(start, len, PG_LEVEL_2M);
63 if (!accept_size)
64 accept_size = try_accept_one(start, len, PG_LEVEL_4K);
65 if (!accept_size)
66 return false;
67 start += accept_size;
68 }
69
70 return true;
71 }
72
73 noinstr u64 __tdx_hypercall(struct tdx_module_args *args)
74 {
75 /*
76 * For TDVMCALL explicitly set RCX to the bitmap of shared registers.
77 * The caller isn't expected to set @args->rcx anyway.
78 */
79 args->rcx = TDVMCALL_EXPOSE_REGS_MASK;
80
81 /*
82 * Failure of __tdcall_saved_ret() indicates a failure of the TDVMCALL
83 * mechanism itself and that something has gone horribly wrong with
84 * the TDX module. __tdx_hypercall_failed() never returns.
85 */
86 if (__tdcall_saved_ret(TDG_VP_VMCALL, args))
87 __tdx_hypercall_failed();
88
89 /* TDVMCALL leaf return code is in R10 */
90 return args->r10;
91 }
92
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