48b3ff0479
XenHypercallLib has two clients at the moment: XenBusDxe and XenConsoleSerialPortLib. Currently, when XenBusDxe starts on a non-Xen X86 platform (ie. as part of OVMF not running on Xen), the X86XenHypercallLib instance built into it fails to initialize, which triggers an ASSERT() in auto-generated code. Instead, let's call XenHypercallIsAvailable() in the driver's entry point, and exit cleanly when the driver is started on a non-Xen platform. Modify the constructor of XenConsoleSerialPortLib similarly; we shouldn't proceed if Xen is not available. In practice this check should never fail, because XenConsoleSerialPortLib is only used on ARM, and ArmXenHypercallLib is always available; but nonetheless we should be pedantic. Reported-by: Gabriel L. Somlo <gsomlo@gmail.com> Suggested-by: Jordan Justen <jordan.l.justen@intel.com> Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Jordan Justen <jordan.l.justen@intel.com> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@17001 6f19259b-4bc3-4df7-8a09-765794883524
103 lines
2.5 KiB
C
103 lines
2.5 KiB
C
/** @file
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Xen Hypercall Library implementation for Intel architecture
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Copyright (c) 2014, Linaro Ltd. All rights reserved.<BR>
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This program and the accompanying materials are licensed and made available under
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the terms and conditions of the BSD License that accompanies this distribution.
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The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php.
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#include <PiDxe.h>
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#include <Library/HobLib.h>
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#include <Library/DebugLib.h>
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#include <Guid/XenInfo.h>
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STATIC VOID *HyperPage;
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/**
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Check if the Xen Hypercall library is able to make calls to the Xen
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hypervisor.
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Client code should call further functions in this library only if, and after,
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this function returns TRUE.
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@retval TRUE Hypercalls are available.
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@retval FALSE Hypercalls are not available.
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**/
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BOOLEAN
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EFIAPI
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XenHypercallIsAvailable (
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VOID
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)
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{
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return HyperPage != NULL;
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}
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//
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// Interface exposed by the ASM implementation of the core hypercall
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//
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INTN
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EFIAPI
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__XenHypercall2 (
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IN VOID *HypercallAddr,
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IN OUT INTN Arg1,
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IN OUT INTN Arg2
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);
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/**
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Library constructor: retrieves the Hyperpage address
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from the gEfiXenInfoGuid HOB
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**/
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RETURN_STATUS
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EFIAPI
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XenHypercallLibInit (
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VOID
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)
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{
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EFI_HOB_GUID_TYPE *GuidHob;
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EFI_XEN_INFO *XenInfo;
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GuidHob = GetFirstGuidHob (&gEfiXenInfoGuid);
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if (GuidHob == NULL) {
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//
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// We don't fail library construction, since that has catastrophic
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// consequences for client modules (whereas those modules may easily be
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// running on a non-Xen platform). Instead, XenHypercallIsAvailable() above
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// will return FALSE.
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//
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return RETURN_SUCCESS;
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}
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XenInfo = (EFI_XEN_INFO *) GET_GUID_HOB_DATA (GuidHob);
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HyperPage = XenInfo->HyperPages;
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return RETURN_SUCCESS;
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}
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/**
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This function will put the two arguments in the right place (registers) and
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invoke the hypercall identified by HypercallID.
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@param HypercallID The symbolic ID of the hypercall to be invoked
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@param Arg1 First argument.
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@param Arg2 Second argument.
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@return Return 0 if success otherwise it return an errno.
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**/
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INTN
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EFIAPI
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XenHypercall2 (
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IN UINTN HypercallID,
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IN OUT INTN Arg1,
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IN OUT INTN Arg2
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)
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{
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ASSERT (HyperPage != NULL);
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return __XenHypercall2 ((UINT8*)HyperPage + HypercallID * 32, Arg1, Arg2);
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}
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