diff options
Diffstat (limited to 'OvmfPkg/XenAcpiPlatformDxe/PciDecoding.c')
| -rw-r--r-- | OvmfPkg/XenAcpiPlatformDxe/PciDecoding.c | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/OvmfPkg/XenAcpiPlatformDxe/PciDecoding.c b/OvmfPkg/XenAcpiPlatformDxe/PciDecoding.c new file mode 100644 index 0000000000..00fc57eb13 --- /dev/null +++ b/OvmfPkg/XenAcpiPlatformDxe/PciDecoding.c @@ -0,0 +1,194 @@ +/** @file
+ Temporarily enable IO and MMIO decoding for all PCI devices while QEMU
+ regenerates the ACPI tables.
+
+ Copyright (C) 2016-2021, Red Hat, Inc.
+
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#include <Library/DebugLib.h> // DEBUG()
+#include <Library/MemoryAllocationLib.h> // AllocatePool()
+#include <Library/UefiBootServicesTableLib.h> // gBS
+
+#include "AcpiPlatform.h"
+
+
+/**
+ Collect all PciIo protocol instances in the system. Save their original
+ attributes, and enable IO and MMIO decoding for each.
+
+ This is a best effort function; it doesn't return status codes. Its
+ caller is supposed to proceed even if this function fails.
+
+ @param[out] OriginalAttributes On output, a dynamically allocated array of
+ ORIGINAL_ATTRIBUTES elements. The array lists
+ the PciIo protocol instances found in the
+ system at the time of the call, plus the
+ original PCI attributes for each.
+
+ Before returning, the function enables IO and
+ MMIO decoding for each PciIo instance it
+ finds.
+
+ On error, or when no such instances are
+ found, OriginalAttributes is set to NULL.
+
+ @param[out] Count On output, the number of elements in
+ OriginalAttributes. On error it is set to
+ zero.
+**/
+VOID
+EnablePciDecoding (
+ OUT ORIGINAL_ATTRIBUTES **OriginalAttributes,
+ OUT UINTN *Count
+ )
+{
+ EFI_STATUS Status;
+ UINTN NoHandles;
+ EFI_HANDLE *Handles;
+ ORIGINAL_ATTRIBUTES *OrigAttrs;
+ UINTN Idx;
+
+ *OriginalAttributes = NULL;
+ *Count = 0;
+
+ if (PcdGetBool (PcdPciDisableBusEnumeration)) {
+ //
+ // The platform downloads ACPI tables from QEMU in general, but there are
+ // no root bridges in this execution. We're done.
+ //
+ return;
+ }
+
+ Status = gBS->LocateHandleBuffer (ByProtocol, &gEfiPciIoProtocolGuid,
+ NULL /* SearchKey */, &NoHandles, &Handles);
+ if (Status == EFI_NOT_FOUND) {
+ //
+ // No PCI devices were found on either of the root bridges. We're done.
+ //
+ return;
+ }
+
+ if (EFI_ERROR (Status)) {
+ DEBUG ((DEBUG_WARN, "%a: LocateHandleBuffer(): %r\n", __FUNCTION__,
+ Status));
+ return;
+ }
+
+ OrigAttrs = AllocatePool (NoHandles * sizeof *OrigAttrs);
+ if (OrigAttrs == NULL) {
+ DEBUG ((DEBUG_WARN, "%a: AllocatePool(): out of resources\n",
+ __FUNCTION__));
+ goto FreeHandles;
+ }
+
+ for (Idx = 0; Idx < NoHandles; ++Idx) {
+ EFI_PCI_IO_PROTOCOL *PciIo;
+ UINT64 Attributes;
+
+ //
+ // Look up PciIo on the handle and stash it
+ //
+ Status = gBS->HandleProtocol (Handles[Idx], &gEfiPciIoProtocolGuid,
+ (VOID**)&PciIo);
+ ASSERT_EFI_ERROR (Status);
+ OrigAttrs[Idx].PciIo = PciIo;
+
+ //
+ // Stash the current attributes
+ //
+ Status = PciIo->Attributes (PciIo, EfiPciIoAttributeOperationGet, 0,
+ &OrigAttrs[Idx].PciAttributes);
+ if (EFI_ERROR (Status)) {
+ DEBUG ((DEBUG_WARN, "%a: EfiPciIoAttributeOperationGet: %r\n",
+ __FUNCTION__, Status));
+ goto RestoreAttributes;
+ }
+
+ //
+ // Retrieve supported attributes
+ //
+ Status = PciIo->Attributes (PciIo, EfiPciIoAttributeOperationSupported, 0,
+ &Attributes);
+ if (EFI_ERROR (Status)) {
+ DEBUG ((DEBUG_WARN, "%a: EfiPciIoAttributeOperationSupported: %r\n",
+ __FUNCTION__, Status));
+ goto RestoreAttributes;
+ }
+
+ //
+ // Enable IO and MMIO decoding
+ //
+ Attributes &= EFI_PCI_IO_ATTRIBUTE_IO | EFI_PCI_IO_ATTRIBUTE_MEMORY;
+ Status = PciIo->Attributes (PciIo, EfiPciIoAttributeOperationEnable,
+ Attributes, NULL);
+ if (EFI_ERROR (Status)) {
+ DEBUG ((DEBUG_WARN, "%a: EfiPciIoAttributeOperationEnable: %r\n",
+ __FUNCTION__, Status));
+ goto RestoreAttributes;
+ }
+ }
+
+ //
+ // Success
+ //
+ FreePool (Handles);
+ *OriginalAttributes = OrigAttrs;
+ *Count = NoHandles;
+ return;
+
+RestoreAttributes:
+ while (Idx > 0) {
+ --Idx;
+ OrigAttrs[Idx].PciIo->Attributes (OrigAttrs[Idx].PciIo,
+ EfiPciIoAttributeOperationSet,
+ OrigAttrs[Idx].PciAttributes,
+ NULL
+ );
+ }
+ FreePool (OrigAttrs);
+
+FreeHandles:
+ FreePool (Handles);
+}
+
+
+/**
+ Restore the original PCI attributes saved with EnablePciDecoding().
+
+ @param[in] OriginalAttributes The array allocated and populated by
+ EnablePciDecoding(). This parameter may be
+ NULL. If OriginalAttributes is NULL, then the
+ function is a no-op; otherwise the PciIo
+ attributes will be restored, and the
+ OriginalAttributes array will be freed.
+
+ @param[in] Count The Count value stored by EnablePciDecoding(),
+ the number of elements in OriginalAttributes.
+ Count may be zero if and only if
+ OriginalAttributes is NULL.
+**/
+VOID
+RestorePciDecoding (
+ IN ORIGINAL_ATTRIBUTES *OriginalAttributes,
+ IN UINTN Count
+ )
+{
+ UINTN Idx;
+
+ ASSERT ((OriginalAttributes == NULL) == (Count == 0));
+ if (OriginalAttributes == NULL) {
+ return;
+ }
+
+ for (Idx = 0; Idx < Count; ++Idx) {
+ OriginalAttributes[Idx].PciIo->Attributes (
+ OriginalAttributes[Idx].PciIo,
+ EfiPciIoAttributeOperationSet,
+ OriginalAttributes[Idx].PciAttributes,
+ NULL
+ );
+ }
+ FreePool (OriginalAttributes);
+}
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