/** @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. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. **/ #include "XenBusDxe.h" #include <IndustryStandard/Xen/memory.h> #include <Library/XenHypercallLib.h> #include <Library/SynchronizationLib.h> #include "GrantTable.h" #define NR_RESERVED_ENTRIES 8 /* NR_GRANT_FRAMES must be less than or equal to that configured in Xen */ #define NR_GRANT_FRAMES 4 #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 ((EFI_D_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 ((EFI_D_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 ((EFI_D_INFO, "Xen GrantTable, removing %Lx\n", (UINT64)Parameters.gpfn)); ReturnCode = XenHypercallMemoryOp (XENMEM_remove_from_physmap, &Parameters); if (ReturnCode != 0) { DEBUG ((EFI_D_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); }