1 /** @file 2 Xen Hypercall Library implementation for Intel architecture 3 4 Copyright (c) 2014, Linaro Ltd. All rights reserved.<BR> 5 This program and the accompanying materials are licensed and made available under 6 the terms and conditions of the BSD License that accompanies this distribution. 7 The full text of the license may be found at 8 http://opensource.org/licenses/bsd-license.php. 9 10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 12 13 **/ 14 15 #include <PiDxe.h> 16 #include <Library/HobLib.h> 17 #include <Library/DebugLib.h> 18 #include <Guid/XenInfo.h> 19 20 STATIC VOID *HyperPage; 21 22 /** 23 Check if the Xen Hypercall library is able to make calls to the Xen 24 hypervisor. 25 26 Client code should call further functions in this library only if, and after, 27 this function returns TRUE. 28 29 @retval TRUE Hypercalls are available. 30 @retval FALSE Hypercalls are not available. 31 **/ 32 BOOLEAN 33 EFIAPI 34 XenHypercallIsAvailable ( 35 VOID 36 ) 37 { 38 return HyperPage != NULL; 39 } 40 41 // 42 // Interface exposed by the ASM implementation of the core hypercall 43 // 44 INTN 45 EFIAPI 46 __XenHypercall2 ( 47 IN VOID *HypercallAddr, 48 IN OUT INTN Arg1, 49 IN OUT INTN Arg2 50 ); 51 52 /** 53 Library constructor: retrieves the Hyperpage address 54 from the gEfiXenInfoGuid HOB 55 **/ 56 57 RETURN_STATUS 58 EFIAPI 59 XenHypercallLibInit ( 60 VOID 61 ) 62 { 63 EFI_HOB_GUID_TYPE *GuidHob; 64 EFI_XEN_INFO *XenInfo; 65 66 GuidHob = GetFirstGuidHob (&gEfiXenInfoGuid); 67 if (GuidHob == NULL) { 68 // 69 // We don't fail library construction, since that has catastrophic 70 // consequences for client modules (whereas those modules may easily be 71 // running on a non-Xen platform). Instead, XenHypercallIsAvailable() above 72 // will return FALSE. 73 // 74 return RETURN_SUCCESS; 75 } 76 XenInfo = (EFI_XEN_INFO *) GET_GUID_HOB_DATA (GuidHob); 77 HyperPage = XenInfo->HyperPages; 78 return RETURN_SUCCESS; 79 } 80 81 /** 82 This function will put the two arguments in the right place (registers) and 83 invoke the hypercall identified by HypercallID. 84 85 @param HypercallID The symbolic ID of the hypercall to be invoked 86 @param Arg1 First argument. 87 @param Arg2 Second argument. 88 89 @return Return 0 if success otherwise it return an errno. 90 **/ 91 INTN 92 EFIAPI 93 XenHypercall2 ( 94 IN UINTN HypercallID, 95 IN OUT INTN Arg1, 96 IN OUT INTN Arg2 97 ) 98 { 99 ASSERT (HyperPage != NULL); 100 101 return __XenHypercall2 ((UINT8*)HyperPage + HypercallID * 32, Arg1, Arg2); 102 } 103
