OvmfPkg/XenBusDxe: Add Grant Table functions.
There are used to grant access of pages to other Xen domains. This code originaly comes from the Xen Project, and more precisely from MiniOS. Change in V4: - Add license to GrantTable.h Change in V3: - Add a comment about the use of the BAR of the device. Change in V2: - Adding locks - Redo the file header - Add functions comment - Add license Signed-off-by: Steven Smith <sos22@cam.ac.uk> Signed-off-by: Grzegorz Milos <gm281@cam.ac.uk> Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Acked-by: Jordan Justen <jordan.l.justen@intel.com> git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16264 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
Steven Smith
jljusten
217
OvmfPkg/XenBusDxe/GrantTable.c
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217
OvmfPkg/XenBusDxe/GrantTable.c
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/** @file
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Grant Table function implementation.
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Grant Table are used to grant access to certain page of the current
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VM to an other VM.
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Author: Steven Smith (sos22@cam.ac.uk)
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Changes: Grzegorz Milos (gm281@cam.ac.uk)
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Copyright (C) 2006, Cambridge University
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Copyright (C) 2014, Citrix Ltd.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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1. Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
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FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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SUCH DAMAGE.
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**/
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#include "XenBusDxe.h"
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#include <IndustryStandard/Xen/memory.h>
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#include "XenHypercall.h"
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#include "GrantTable.h"
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#include "InterlockedCompareExchange16.h"
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#define NR_RESERVED_ENTRIES 8
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/* NR_GRANT_FRAMES must be less than or equal to that configured in Xen */
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#define NR_GRANT_FRAMES 4
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#define NR_GRANT_ENTRIES (NR_GRANT_FRAMES * EFI_PAGE_SIZE / sizeof(grant_entry_v1_t))
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STATIC grant_entry_v1_t *GrantTable = NULL;
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STATIC grant_ref_t GrantList[NR_GRANT_ENTRIES];
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STATIC EFI_LOCK mGrantListLock;
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#ifdef GNT_DEBUG
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STATIC BOOLEAN GrantInUseList[NR_GRANT_ENTRIES];
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#endif
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STATIC
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VOID
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XenGrantTablePutFreeEntry (
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grant_ref_t Ref
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)
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{
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EfiAcquireLock (&mGrantListLock);
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#ifdef GNT_DEBUG
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ASSERT (GrantInUseList[Ref]);
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GrantInUseList[Ref] = FALSE;
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#endif
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GrantList[Ref] = GrantList[0];
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GrantList[0] = Ref;
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EfiReleaseLock (&mGrantListLock);
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}
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STATIC
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grant_ref_t
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XenGrantTableGetFreeEntry (
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VOID
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)
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{
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UINTN Ref;
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EfiAcquireLock (&mGrantListLock);
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Ref = GrantList[0];
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ASSERT (Ref >= NR_RESERVED_ENTRIES && Ref < NR_GRANT_ENTRIES);
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GrantList[0] = GrantList[Ref];
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#ifdef GNT_DEBUG
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ASSERT (!GrantInUseList[Ref]);
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GrantInUseList[Ref] = TRUE;
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#endif
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EfiReleaseLock (&mGrantListLock);
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return Ref;
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}
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STATIC
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grant_ref_t
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XenGrantTableGrantAccess (
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IN domid_t DomainId,
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IN UINTN Frame,
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IN BOOLEAN ReadOnly
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)
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{
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grant_ref_t Ref;
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UINT32 Flags;
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ASSERT (GrantTable != NULL);
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Ref = XenGrantTableGetFreeEntry ();
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GrantTable[Ref].frame = Frame;
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GrantTable[Ref].domid = DomainId;
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MemoryFence ();
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Flags = GTF_permit_access;
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if (ReadOnly) {
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Flags |= GTF_readonly;
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}
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GrantTable[Ref].flags = Flags;
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return Ref;
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}
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STATIC
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EFI_STATUS
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XenGrantTableEndAccess (
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grant_ref_t Ref
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)
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{
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UINT16 Flags, OldFlags;
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ASSERT (GrantTable != NULL);
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ASSERT (Ref >= NR_RESERVED_ENTRIES && Ref < NR_GRANT_ENTRIES);
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OldFlags = GrantTable[Ref].flags;
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do {
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if ((Flags = OldFlags) & (GTF_reading | GTF_writing)) {
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DEBUG ((EFI_D_WARN, "WARNING: g.e. still in use! (%x)\n", Flags));
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return EFI_NOT_READY;
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}
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OldFlags = InterlockedCompareExchange16 (&GrantTable[Ref].flags, Flags, 0);
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} while (OldFlags != Flags);
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XenGrantTablePutFreeEntry (Ref);
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return EFI_SUCCESS;
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}
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VOID
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XenGrantTableInit (
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IN XENBUS_DEVICE *Dev,
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IN UINT64 MmioAddr
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)
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{
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xen_add_to_physmap_t Parameters;
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INTN Index;
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INTN ReturnCode;
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#ifdef GNT_DEBUG
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SetMem(GrantInUseList, sizeof (GrantInUseList), 1);
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#endif
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EfiInitializeLock (&mGrantListLock, TPL_NOTIFY);
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for (Index = NR_RESERVED_ENTRIES; Index < NR_GRANT_ENTRIES; Index++) {
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XenGrantTablePutFreeEntry (Index);
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}
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GrantTable = (VOID*)(UINTN) MmioAddr;
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for (Index = 0; Index < NR_GRANT_FRAMES; Index++) {
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Parameters.domid = DOMID_SELF;
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Parameters.idx = Index;
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Parameters.space = XENMAPSPACE_grant_table;
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Parameters.gpfn = (((xen_pfn_t) GrantTable) >> EFI_PAGE_SHIFT) + Index;
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ReturnCode = XenHypercallMemoryOp (Dev, XENMEM_add_to_physmap, &Parameters);
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if (ReturnCode != 0) {
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DEBUG ((EFI_D_ERROR, "Xen GrantTable, add_to_physmap hypercall error: %d\n", ReturnCode));
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}
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}
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}
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VOID
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XenGrantTableDeinit (
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XENBUS_DEVICE *Dev
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)
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{
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INTN ReturnCode, Index;
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xen_remove_from_physmap_t Parameters;
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if (GrantTable == NULL) {
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return;
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}
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for (Index = NR_GRANT_FRAMES - 1; Index >= 0; Index--) {
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Parameters.domid = DOMID_SELF;
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Parameters.gpfn = (((xen_pfn_t) GrantTable) >> EFI_PAGE_SHIFT) + Index;
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DEBUG ((EFI_D_INFO, "Xen GrantTable, removing %X\n", Parameters.gpfn));
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ReturnCode = XenHypercallMemoryOp (Dev, XENMEM_remove_from_physmap, &Parameters);
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if (ReturnCode != 0) {
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DEBUG ((EFI_D_ERROR, "Xen GrantTable, remove_from_physmap hypercall error: %d\n", ReturnCode));
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}
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}
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GrantTable = NULL;
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}
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EFI_STATUS
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EFIAPI
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XenBusGrantAccess (
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IN XENBUS_PROTOCOL *This,
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IN domid_t DomainId,
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IN UINTN Frame, // MFN
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IN BOOLEAN ReadOnly,
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OUT grant_ref_t *RefPtr
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)
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{
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*RefPtr = XenGrantTableGrantAccess (DomainId, Frame, ReadOnly);
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return EFI_SUCCESS;
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}
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EFI_STATUS
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EFIAPI
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XenBusGrantEndAccess (
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IN XENBUS_PROTOCOL *This,
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IN grant_ref_t Ref
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)
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{
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return XenGrantTableEndAccess (Ref);
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}
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