68f4599dfc
Allow to use Xen hypercalls earlier, during the PEIM stage, but XenHypercallLibInit() must be called once the XenInfo HOB is created with the HyperPage setup. Change the return value of XenHypercallLibInit so failure can be detected when the call shouldn't fail, but still have the constructor always succeed. Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1689 Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com> Message-Id: <20190813113119.14804-17-anthony.perard@citrix.com>
91 lines
1.9 KiB
C
91 lines
1.9 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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SPDX-License-Identifier: BSD-2-Clause-Patent
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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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return RETURN_NOT_FOUND;
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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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