OvmfPkg: Replace BSD License with BSD+Patent License

[mirror_edk2.git] / OvmfPkg / XenBusDxe / GrantTable.c

/** @file\r
  Grant Table function implementation.\r
\r
  Grant Table are used to grant access to certain page of the current\r
  VM to an other VM.\r
\r
  Author: Steven Smith (sos22@cam.ac.uk)\r
  Changes: Grzegorz Milos (gm281@cam.ac.uk)\r
  Copyright (C) 2006, Cambridge University\r
  Copyright (C) 2014, Citrix Ltd.\r
\r
  SPDX-License-Identifier: BSD-2-Clause-Patent\r
**/\r
#include "XenBusDxe.h"\r
\r
#include <IndustryStandard/Xen/memory.h>\r
\r
#include <Library/XenHypercallLib.h>\r
#include <Library/SynchronizationLib.h>\r
\r
#include "GrantTable.h"\r
\r
#define NR_RESERVED_ENTRIES 8\r
\r
/* NR_GRANT_FRAMES must be less than or equal to that configured in Xen */\r
#define NR_GRANT_FRAMES 4\r
#define NR_GRANT_ENTRIES (NR_GRANT_FRAMES * EFI_PAGE_SIZE / sizeof(grant_entry_v1_t))\r
\r
STATIC grant_entry_v1_t *GrantTable = NULL;\r
STATIC grant_ref_t GrantList[NR_GRANT_ENTRIES];\r
STATIC EFI_LOCK mGrantListLock;\r
#ifdef GNT_DEBUG\r
STATIC BOOLEAN GrantInUseList[NR_GRANT_ENTRIES];\r
#endif\r
\r
STATIC\r
VOID\r
XenGrantTablePutFreeEntry (\r
  grant_ref_t Ref\r
  )\r
{\r
  EfiAcquireLock (&mGrantListLock);\r
#ifdef GNT_DEBUG\r
  ASSERT (GrantInUseList[Ref]);\r
  GrantInUseList[Ref] = FALSE;\r
#endif\r
  GrantList[Ref] = GrantList[0];\r
  GrantList[0] = Ref;\r
  EfiReleaseLock (&mGrantListLock);\r
}\r
\r
STATIC\r
grant_ref_t\r
XenGrantTableGetFreeEntry (\r
  VOID\r
  )\r
{\r
  grant_ref_t Ref;\r
\r
  EfiAcquireLock (&mGrantListLock);\r
  Ref = GrantList[0];\r
  ASSERT (Ref >= NR_RESERVED_ENTRIES && Ref < NR_GRANT_ENTRIES);\r
  GrantList[0] = GrantList[Ref];\r
#ifdef GNT_DEBUG\r
  ASSERT (!GrantInUseList[Ref]);\r
  GrantInUseList[Ref] = TRUE;\r
#endif\r
  EfiReleaseLock (&mGrantListLock);\r
  return Ref;\r
}\r
\r
STATIC\r
grant_ref_t\r
XenGrantTableGrantAccess (\r
  IN domid_t  DomainId,\r
  IN UINTN    Frame,\r
  IN BOOLEAN  ReadOnly\r
  )\r
{\r
  grant_ref_t Ref;\r
  UINT16 Flags;\r
\r
  ASSERT (GrantTable != NULL);\r
  Ref = XenGrantTableGetFreeEntry ();\r
  GrantTable[Ref].frame = (UINT32)Frame;\r
  GrantTable[Ref].domid = DomainId;\r
  MemoryFence ();\r
  Flags = GTF_permit_access;\r
  if (ReadOnly) {\r
    Flags |= GTF_readonly;\r
  }\r
  GrantTable[Ref].flags = Flags;\r
\r
  return Ref;\r
}\r
\r
STATIC\r
EFI_STATUS\r
XenGrantTableEndAccess (\r
  grant_ref_t Ref\r
  )\r
{\r
  UINT16 Flags, OldFlags;\r
\r
  ASSERT (GrantTable != NULL);\r
  ASSERT (Ref >= NR_RESERVED_ENTRIES && Ref < NR_GRANT_ENTRIES);\r
\r
  OldFlags = GrantTable[Ref].flags;\r
  do {\r
    if ((Flags = OldFlags) & (GTF_reading | GTF_writing)) {\r
      DEBUG ((EFI_D_WARN, "WARNING: g.e. still in use! (%x)\n", Flags));\r
      return EFI_NOT_READY;\r
    }\r
    OldFlags = InterlockedCompareExchange16 (&GrantTable[Ref].flags, Flags, 0);\r
  } while (OldFlags != Flags);\r
\r
  XenGrantTablePutFreeEntry (Ref);\r
  return EFI_SUCCESS;\r
}\r
\r
VOID\r
XenGrantTableInit (\r
  IN XENBUS_DEVICE  *Dev\r
  )\r
{\r
  xen_add_to_physmap_t Parameters;\r
  INTN Index;\r
  INTN ReturnCode;\r
\r
#ifdef GNT_DEBUG\r
  SetMem(GrantInUseList, sizeof (GrantInUseList), 1);\r
#endif\r
  EfiInitializeLock (&mGrantListLock, TPL_NOTIFY);\r
  for (Index = NR_RESERVED_ENTRIES; Index < NR_GRANT_ENTRIES; Index++) {\r
    XenGrantTablePutFreeEntry ((grant_ref_t)Index);\r
  }\r
\r
  GrantTable = (VOID*)(UINTN) Dev->XenIo->GrantTableAddress;\r
  for (Index = 0; Index < NR_GRANT_FRAMES; Index++) {\r
    Parameters.domid = DOMID_SELF;\r
    Parameters.idx = Index;\r
    Parameters.space = XENMAPSPACE_grant_table;\r
    Parameters.gpfn = (xen_pfn_t) ((UINTN) GrantTable >> EFI_PAGE_SHIFT) + Index;\r
    ReturnCode = XenHypercallMemoryOp (XENMEM_add_to_physmap, &Parameters);\r
    if (ReturnCode != 0) {\r
      DEBUG ((EFI_D_ERROR,\r
        "Xen GrantTable, add_to_physmap hypercall error: %Ld\n",\r
        (INT64)ReturnCode));\r
    }\r
  }\r
}\r
\r
VOID\r
XenGrantTableDeinit (\r
  XENBUS_DEVICE *Dev\r
  )\r
{\r
  INTN ReturnCode, Index;\r
  xen_remove_from_physmap_t Parameters;\r
\r
  if (GrantTable == NULL) {\r
    return;\r
  }\r
\r
  for (Index = NR_GRANT_FRAMES - 1; Index >= 0; Index--) {\r
    Parameters.domid = DOMID_SELF;\r
    Parameters.gpfn = (xen_pfn_t) ((UINTN) GrantTable >> EFI_PAGE_SHIFT) + Index;\r
    DEBUG ((EFI_D_INFO, "Xen GrantTable, removing %Lx\n",\r
      (UINT64)Parameters.gpfn));\r
    ReturnCode = XenHypercallMemoryOp (XENMEM_remove_from_physmap, &Parameters);\r
    if (ReturnCode != 0) {\r
      DEBUG ((EFI_D_ERROR,\r
        "Xen GrantTable, remove_from_physmap hypercall error: %Ld\n",\r
        (INT64)ReturnCode));\r
    }\r
  }\r
  GrantTable = NULL;\r
}\r
\r
EFI_STATUS\r
EFIAPI\r
XenBusGrantAccess (\r
  IN  XENBUS_PROTOCOL *This,\r
  IN  domid_t         DomainId,\r
  IN  UINTN           Frame, // MFN\r
  IN  BOOLEAN         ReadOnly,\r
  OUT grant_ref_t     *RefPtr\r
  )\r
{\r
  *RefPtr = XenGrantTableGrantAccess (DomainId, Frame, ReadOnly);\r
  return EFI_SUCCESS;\r
}\r
\r
EFI_STATUS\r
EFIAPI\r
XenBusGrantEndAccess (\r
  IN XENBUS_PROTOCOL  *This,\r
  IN grant_ref_t      Ref\r
  )\r
{\r
  return XenGrantTableEndAccess (Ref);\r
}\r