1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Secure VM platform
4  *
5  * Copyright 2018 IBM Corporation
6  * Author: Anshuman Khandual <khandual@linux.vnet.ibm.com>
7  */
8 
9 #include <linux/mm.h>
10 #include <linux/memblock.h>
11 #include <asm/machdep.h>
12 #include <asm/svm.h>
13 #include <asm/swiotlb.h>
14 #include <asm/ultravisor.h>
15 #include <asm/dtl.h>
16 
17 static int __init init_svm(void)
18 {
19 	if (!is_secure_guest())
20 		return 0;
21 
22 	/* Don't release the SWIOTLB buffer. */
23 	ppc_swiotlb_enable = 1;
24 
25 	/*
26 	 * Since the guest memory is inaccessible to the host, devices always
27 	 * need to use the SWIOTLB buffer for DMA even if dma_capable() says
28 	 * otherwise.
29 	 */
30 	swiotlb_force = SWIOTLB_FORCE;
31 
32 	/* Share the SWIOTLB buffer with the host. */
33 	swiotlb_update_mem_attributes();
34 
35 	return 0;
36 }
37 machine_early_initcall(pseries, init_svm);
38 
39 /*
40  * Initialize SWIOTLB. Essentially the same as swiotlb_init(), except that it
41  * can allocate the buffer anywhere in memory. Since the hypervisor doesn't have
42  * any addressing limitation, we don't need to allocate it in low addresses.
43  */
44 void __init svm_swiotlb_init(void)
45 {
46 	unsigned char *vstart;
47 	unsigned long bytes, io_tlb_nslabs;
48 
49 	io_tlb_nslabs = (swiotlb_size_or_default() >> IO_TLB_SHIFT);
50 	io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
51 
52 	bytes = io_tlb_nslabs << IO_TLB_SHIFT;
53 
54 	vstart = memblock_alloc(PAGE_ALIGN(bytes), PAGE_SIZE);
55 	if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs, false))
56 		return;
57 
58 	if (io_tlb_start)
59 		memblock_free_early(io_tlb_start,
60 				    PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
61 	panic("SVM: Cannot allocate SWIOTLB buffer");
62 }
63 
64 int set_memory_encrypted(unsigned long addr, int numpages)
65 {
66 	if (!PAGE_ALIGNED(addr))
67 		return -EINVAL;
68 
69 	uv_unshare_page(PHYS_PFN(__pa(addr)), numpages);
70 
71 	return 0;
72 }
73 
74 int set_memory_decrypted(unsigned long addr, int numpages)
75 {
76 	if (!PAGE_ALIGNED(addr))
77 		return -EINVAL;
78 
79 	uv_share_page(PHYS_PFN(__pa(addr)), numpages);
80 
81 	return 0;
82 }
83 
84 /* There's one dispatch log per CPU. */
85 #define NR_DTL_PAGE (DISPATCH_LOG_BYTES * CONFIG_NR_CPUS / PAGE_SIZE)
86 
87 static struct page *dtl_page_store[NR_DTL_PAGE];
88 static long dtl_nr_pages;
89 
90 static bool is_dtl_page_shared(struct page *page)
91 {
92 	long i;
93 
94 	for (i = 0; i < dtl_nr_pages; i++)
95 		if (dtl_page_store[i] == page)
96 			return true;
97 
98 	return false;
99 }
100 
101 void dtl_cache_ctor(void *addr)
102 {
103 	unsigned long pfn = PHYS_PFN(__pa(addr));
104 	struct page *page = pfn_to_page(pfn);
105 
106 	if (!is_dtl_page_shared(page)) {
107 		dtl_page_store[dtl_nr_pages] = page;
108 		dtl_nr_pages++;
109 		WARN_ON(dtl_nr_pages >= NR_DTL_PAGE);
110 		uv_share_page(pfn, 1);
111 	}
112 }
113