Files
system76-edk2/OvmfPkg/Library/ResetSystemLib/DxeResetShutdown.c
Laszlo Ersek 93f6df5f3b OvmfPkg/ResetSystemLib: introduce the DxeResetSystemLib instance
The BaseResetSystemLib instance is not suitable for OS runtime, because
its ResetShutdown() implementation calls PciRead16 (OVMF_HOSTBRIDGE_DID).
On q35, this boils down to a memory-mapped config space access -- but we
never ask the OS to map MMCONFIG for runtime.

There are at least three alternatives to approach this:

(1) Investigate "MdePkg/Library/DxeRuntimePciExpressLib", which offers
    some kind of runtime mapping for MMCONFIG.

(2) Consume PciCf8Lib directly, rather than PciLib, in ResetSystemLib.
    Then we'll read OVMF_HOSTBRIDGE_DID from the config space with IO port
    accesses on q35 too, not just on i440fx. IO ports don't depend on page
    tables.

(3) In the lib constructor, cache "mAcpiPmBaseAddress" based on
    "PcdOvmfHostBridgePciDevId" (which is set by PlatformPei). Then the
    host bridge type will be known at runtime without PCI config space
    accesses.

This patch follows approach (3), in order to mirror AcpiTimerLib.

Notes:

* This patch is best viewed with "git show --find-copies-harder -C43".

* PCDs are not usable in the DXE_CORE, as the PCD PPI is gone, and the PCD
  protocol is not available yet. (The DXE_CORE does consume ResetSystemLib
  in practice, when OVMF is built with -D SOURCE_DEBUG_ENABLE.)

Cc: Anthony Perard <anthony.perard@citrix.com>
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Julien Grall <julien@xen.org>
Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
Cc: Rebecca Cran <rebecca@bsdio.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2675
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20200417153751.7110-7-lersek@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
Reviewed-by: Rebecca Cran <rebecca@bsdio.com>
[lersek@redhat.com: move third Note (with repro info) to BZ comment]
2020-04-22 19:42:32 +00:00

63 lines
1.5 KiB
C

/** @file
DXE Reset System Library Shutdown API implementation for OVMF.
Copyright (C) 2020, Red Hat, Inc.
Copyright (c) 2006 - 2019, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Base.h> // BIT13
#include <Library/BaseLib.h> // CpuDeadLoop()
#include <Library/DebugLib.h> // ASSERT()
#include <Library/IoLib.h> // IoOr16()
#include <Library/PcdLib.h> // PcdGet16()
#include <Library/ResetSystemLib.h> // ResetShutdown()
#include <OvmfPlatforms.h> // PIIX4_PMBA_VALUE
STATIC UINT16 mAcpiPmBaseAddress;
EFI_STATUS
EFIAPI
DxeResetInit (
IN EFI_HANDLE ImageHandle,
IN EFI_SYSTEM_TABLE *SystemTable
)
{
UINT16 HostBridgeDevId;
HostBridgeDevId = PcdGet16 (PcdOvmfHostBridgePciDevId);
switch (HostBridgeDevId) {
case INTEL_82441_DEVICE_ID:
mAcpiPmBaseAddress = PIIX4_PMBA_VALUE;
break;
case INTEL_Q35_MCH_DEVICE_ID:
mAcpiPmBaseAddress = ICH9_PMBASE_VALUE;
break;
default:
ASSERT (FALSE);
CpuDeadLoop ();
return EFI_UNSUPPORTED;
}
return EFI_SUCCESS;
}
/**
Calling this function causes the system to enter a power state equivalent
to the ACPI G2/S5 or G3 states.
System shutdown should not return, if it returns, it means the system does
not support shut down reset.
**/
VOID
EFIAPI
ResetShutdown (
VOID
)
{
IoBitFieldWrite16 (mAcpiPmBaseAddress + 4, 10, 13, 0);
IoOr16 (mAcpiPmBaseAddress + 4, BIT13);
CpuDeadLoop ();
}