svm.c

 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 <linux/mem_encrypt.h>
12#include <linux/cc_platform.h>
13#include <asm/machdep.h>
14#include <asm/svm.h>
15#include <asm/swiotlb.h>
16#include <asm/ultravisor.h>
17#include <asm/dtl.h>
18
19static int __init init_svm(void)
20{
21	if (!is_secure_guest())
22		return 0;
23
24	/* Don't release the SWIOTLB buffer. */
25	ppc_swiotlb_enable = 1;
26
27	/*
28	 * Since the guest memory is inaccessible to the host, devices always
29	 * need to use the SWIOTLB buffer for DMA even if dma_capable() says
30	 * otherwise.
31	 */
32	ppc_swiotlb_flags |= SWIOTLB_ANY | SWIOTLB_FORCE;
33
34	/* Share the SWIOTLB buffer with the host. */
35	swiotlb_update_mem_attributes();
36
37	return 0;
38}
39machine_early_initcall(pseries, init_svm);
40
41int set_memory_encrypted(unsigned long addr, int numpages)
42{
43	if (!cc_platform_has(CC_ATTR_MEM_ENCRYPT))
44		return 0;
45
46	if (!PAGE_ALIGNED(addr))
47		return -EINVAL;
48
49	uv_unshare_page(PHYS_PFN(__pa(addr)), numpages);
50
51	return 0;
52}
53
54int set_memory_decrypted(unsigned long addr, int numpages)
55{
56	if (!cc_platform_has(CC_ATTR_MEM_ENCRYPT))
57		return 0;
58
59	if (!PAGE_ALIGNED(addr))
60		return -EINVAL;
61
62	uv_share_page(PHYS_PFN(__pa(addr)), numpages);
63
64	return 0;
65}
66
67/* There's one dispatch log per CPU. */
68#define NR_DTL_PAGE (DISPATCH_LOG_BYTES * CONFIG_NR_CPUS / PAGE_SIZE)
69
70static struct page *dtl_page_store[NR_DTL_PAGE];
71static long dtl_nr_pages;
72
73static bool is_dtl_page_shared(struct page *page)
74{
75	long i;
76
77	for (i = 0; i < dtl_nr_pages; i++)
78		if (dtl_page_store[i] == page)
79			return true;
80
81	return false;
82}
83
84void dtl_cache_ctor(void *addr)
85{
86	unsigned long pfn = PHYS_PFN(__pa(addr));
87	struct page *page = pfn_to_page(pfn);
88
89	if (!is_dtl_page_shared(page)) {
90		dtl_page_store[dtl_nr_pages] = page;
91		dtl_nr_pages++;
92		WARN_ON(dtl_nr_pages >= NR_DTL_PAGE);
93		uv_share_page(pfn, 1);
94	}
95}