arch/powerpc/platforms/pseries/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 <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 }