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- /** @file
- Grant Table function implementation.
- Grant Table are used to grant access to certain page of the current
- VM to an other VM.
- Author: Steven Smith (sos22@cam.ac.uk)
- Changes: Grzegorz Milos (gm281@cam.ac.uk)
- Copyright (C) 2006, Cambridge University
- Copyright (C) 2014, Citrix Ltd.
- SPDX-License-Identifier: BSD-2-Clause-Patent
- **/
- #include "XenBusDxe.h"
- #include <IndustryStandard/Xen/memory.h>
- #include <Library/XenHypercallLib.h>
- #include <Library/SynchronizationLib.h>
- #include "GrantTable.h"
- #define NR_RESERVED_ENTRIES 8
- #define NR_GRANT_FRAMES (FixedPcdGet32 (PcdXenGrantFrames))
- #define NR_GRANT_ENTRIES (NR_GRANT_FRAMES * EFI_PAGE_SIZE / sizeof(grant_entry_v1_t))
- STATIC grant_entry_v1_t *GrantTable = NULL;
- STATIC grant_ref_t GrantList[NR_GRANT_ENTRIES];
- STATIC EFI_LOCK mGrantListLock;
- #ifdef GNT_DEBUG
- STATIC BOOLEAN GrantInUseList[NR_GRANT_ENTRIES];
- #endif
- STATIC
- VOID
- XenGrantTablePutFreeEntry (
- grant_ref_t Ref
- )
- {
- EfiAcquireLock (&mGrantListLock);
- #ifdef GNT_DEBUG
- ASSERT (GrantInUseList[Ref]);
- GrantInUseList[Ref] = FALSE;
- #endif
- GrantList[Ref] = GrantList[0];
- GrantList[0] = Ref;
- EfiReleaseLock (&mGrantListLock);
- }
- STATIC
- grant_ref_t
- XenGrantTableGetFreeEntry (
- VOID
- )
- {
- grant_ref_t Ref;
- EfiAcquireLock (&mGrantListLock);
- Ref = GrantList[0];
- ASSERT (Ref >= NR_RESERVED_ENTRIES && Ref < NR_GRANT_ENTRIES);
- GrantList[0] = GrantList[Ref];
- #ifdef GNT_DEBUG
- ASSERT (!GrantInUseList[Ref]);
- GrantInUseList[Ref] = TRUE;
- #endif
- EfiReleaseLock (&mGrantListLock);
- return Ref;
- }
- STATIC
- grant_ref_t
- XenGrantTableGrantAccess (
- IN domid_t DomainId,
- IN UINTN Frame,
- IN BOOLEAN ReadOnly
- )
- {
- grant_ref_t Ref;
- UINT16 Flags;
- ASSERT (GrantTable != NULL);
- Ref = XenGrantTableGetFreeEntry ();
- GrantTable[Ref].frame = (UINT32)Frame;
- GrantTable[Ref].domid = DomainId;
- MemoryFence ();
- Flags = GTF_permit_access;
- if (ReadOnly) {
- Flags |= GTF_readonly;
- }
- GrantTable[Ref].flags = Flags;
- return Ref;
- }
- STATIC
- EFI_STATUS
- XenGrantTableEndAccess (
- grant_ref_t Ref
- )
- {
- UINT16 Flags, OldFlags;
- ASSERT (GrantTable != NULL);
- ASSERT (Ref >= NR_RESERVED_ENTRIES && Ref < NR_GRANT_ENTRIES);
- OldFlags = GrantTable[Ref].flags;
- do {
- if ((Flags = OldFlags) & (GTF_reading | GTF_writing)) {
- DEBUG ((DEBUG_WARN, "WARNING: g.e. still in use! (%x)\n", Flags));
- return EFI_NOT_READY;
- }
- OldFlags = InterlockedCompareExchange16 (&GrantTable[Ref].flags, Flags, 0);
- } while (OldFlags != Flags);
- XenGrantTablePutFreeEntry (Ref);
- return EFI_SUCCESS;
- }
- VOID
- XenGrantTableInit (
- IN XENBUS_DEVICE *Dev
- )
- {
- xen_add_to_physmap_t Parameters;
- INTN Index;
- INTN ReturnCode;
- #ifdef GNT_DEBUG
- SetMem (GrantInUseList, sizeof (GrantInUseList), 1);
- #endif
- EfiInitializeLock (&mGrantListLock, TPL_NOTIFY);
- for (Index = NR_RESERVED_ENTRIES; Index < NR_GRANT_ENTRIES; Index++) {
- XenGrantTablePutFreeEntry ((grant_ref_t)Index);
- }
- GrantTable = (VOID *)(UINTN)Dev->XenIo->GrantTableAddress;
- for (Index = 0; Index < NR_GRANT_FRAMES; Index++) {
- Parameters.domid = DOMID_SELF;
- Parameters.idx = Index;
- Parameters.space = XENMAPSPACE_grant_table;
- Parameters.gpfn = (xen_pfn_t)((UINTN)GrantTable >> EFI_PAGE_SHIFT) + Index;
- ReturnCode = XenHypercallMemoryOp (XENMEM_add_to_physmap, &Parameters);
- if (ReturnCode != 0) {
- DEBUG ((
- DEBUG_ERROR,
- "Xen GrantTable, add_to_physmap hypercall error: %Ld\n",
- (INT64)ReturnCode
- ));
- }
- }
- }
- VOID
- XenGrantTableDeinit (
- XENBUS_DEVICE *Dev
- )
- {
- INTN ReturnCode, Index;
- xen_remove_from_physmap_t Parameters;
- if (GrantTable == NULL) {
- return;
- }
- for (Index = NR_GRANT_FRAMES - 1; Index >= 0; Index--) {
- Parameters.domid = DOMID_SELF;
- Parameters.gpfn = (xen_pfn_t)((UINTN)GrantTable >> EFI_PAGE_SHIFT) + Index;
- DEBUG ((
- DEBUG_INFO,
- "Xen GrantTable, removing %Lx\n",
- (UINT64)Parameters.gpfn
- ));
- ReturnCode = XenHypercallMemoryOp (XENMEM_remove_from_physmap, &Parameters);
- if (ReturnCode != 0) {
- DEBUG ((
- DEBUG_ERROR,
- "Xen GrantTable, remove_from_physmap hypercall error: %Ld\n",
- (INT64)ReturnCode
- ));
- }
- }
- GrantTable = NULL;
- }
- EFI_STATUS
- EFIAPI
- XenBusGrantAccess (
- IN XENBUS_PROTOCOL *This,
- IN domid_t DomainId,
- IN UINTN Frame, // MFN
- IN BOOLEAN ReadOnly,
- OUT grant_ref_t *RefPtr
- )
- {
- *RefPtr = XenGrantTableGrantAccess (DomainId, Frame, ReadOnly);
- return EFI_SUCCESS;
- }
- EFI_STATUS
- EFIAPI
- XenBusGrantEndAccess (
- IN XENBUS_PROTOCOL *This,
- IN grant_ref_t Ref
- )
- {
- return XenGrantTableEndAccess (Ref);
- }
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