In commit 8057622527 ("OvmfPkg/AcpiPlatformDxe: save fw_cfg boot script
with QemuFwCfgS3Lib", 2017-02-23), we replaced the explicit S3 boot script
manipulation in TransferS3ContextToBootScript() with a call to
QemuFwCfgS3CallWhenBootScriptReady(). (Passing AppendFwCfgBootScript() as
callback.)
QemuFwCfgS3CallWhenBootScriptReady() checks for fw_cfg DMA up-front, and
bails with RETURN_NOT_FOUND if fw_cfg DMA is missing.
(This is justified as the goal of QemuFwCfgS3Lib is to "enable[] driver
modules [...] to produce fw_cfg DMA operations that are to be replayed at
S3 resume time".)
In turn, if QemuFwCfgS3CallWhenBootScriptReady() fails, then
OvmfPkg/AcpiPlatformDxe rolls back any earlier linker/loader script
processing, and falls back to the built-in ACPI tables.
(This is also justified because failure to save WRITE_POINTER commands for
replaying at S3 resume implies failure to process the linker/loader script
comprehensively.)
Calling QemuFwCfgS3CallWhenBootScriptReady() from
TransferS3ContextToBootScript() *unconditionally* is wrong however. For
the case when the linker/loader script contains no WRITE_POINTER commands,
the call perpetuated an earlier side effect, and introduced another one:
(1) On machine types that provide fw_cfg DMA (i.e., 2.5+),
QemuFwCfgS3CallWhenBootScriptReady() would succeed, and allocate
workspace for the boot script opcodes in reserved memory. However, no
opcodes would actually be produced in the AppendFwCfgBootScript()
callback, due to lack of any WRITE_POINTER commands.
This waste of reserved memory had been introduced in earlier commit
df73df138d ("OvmfPkg/AcpiPlatformDxe: replay
QEMU_LOADER_WRITE_POINTER commands at S3", 2017-02-09).
(2) On machine types that lack fw_cfg DMA (i.e., 2.4 and earlier),
TransferS3ContextToBootScript() would now fail the linker/loader
script for no reason.
(Note that QEMU itself prevents adding devices that depend on
WRITE_POINTER if the machine type lacks fw_cfg DMA:
$ qemu-system-x86_64 -M pc-q35-2.4 -device vmgenid
qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write
support in fw_cfg, which this machine type does not provide)
Short-circuit an empty S3_CONTEXT in TransferS3ContextToBootScript() by
dropping S3_CONTEXT on the floor. This is compatible with the current
contract of the function as it constitutes a transfer of ownership.
Regression (2) was found and reported by Dhiru Kholia as an OSX guest boot
failure on the "pc-q35-2.4" machine type:
http://mid.mail-archive.com/CANO7a6x6EaWNZ8y=MvLU=w_LjRLXserO3NmsgHvaYE0aUCCWzg@mail.gmail.com
Dhiru bisected the issue to commit 8057622527.
Cc: Dhiru Kholia <dhiru.kholia@gmail.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Fixes: df73df138d
Fixes: 8057622527
Reported-by: Dhiru Kholia <dhiru.kholia@gmail.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Dhiru Kholia <dhiru.kholia@gmail.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Drop the explicit S3SaveState protocol and opcode management; instead,
create ACPI S3 Boot Script opcodes for the WRITE_POINTER commands with
QemuFwCfgS3Lib functions.
In this case, we have a dynamically allocated Context structure, hence the
patch demonstrates how the FW_CFG_BOOT_SCRIPT_CALLBACK_FUNCTION takes
ownership of Context.
Cc: Jordan Justen <jordan.l.justen@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=394
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Introduce the FW_CFG_IO_DMA_ADDRESS macro for IO Ports 0x514 and 0x518
(most significant and least significant halves of the DMA Address
Register, respectively), and update all references in OvmfPkg.
Cc: Jordan Justen <jordan.l.justen@intel.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>
Commit df73df138d ("OvmfPkg/AcpiPlatformDxe: replay
QEMU_LOADER_WRITE_POINTER commands at S3", 2017-02-09) added
"BootScript.c" with such comments on the PointerValue field of
CONDENSED_WRITE_POINTER, and on the corresponding PointerValue parameter
of SaveCondensedWritePointerToS3Context(), that did not consider the
then-latest update of the QEMU_LOADER_WRITE_POINTER structure. (Namely,
the introduction of the PointeeOffset field.)
The code is fine as-is -- ProcessCmdWritePointer() already calls
SaveCondensedWritePointerToS3Context() correctly, and "BootScript.c"
itself is indifferent to the exact values --, but the comments in
"BootScript.c" should match reality too. Update them.
Cc: 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>
Ultimately, each QEMU_LOADER_WRITE_POINTER command creates a guest memory
reference in some QEMU device. When the virtual machine is reset, the
device willfully forgets the guest address, since the guest memory is
wholly invalidated during platform reset.
... Unless the reset is part of S3 resume. Then the guest memory is
preserved intact, and the firmware must reprogram those devices with the
original guest memory allocation addresses.
This patch accumulates the fw_cfg select, skip and write operations of
ProcessCmdWritePointer() in a validated / condensed form, and turns them
into an ACPI S3 Boot Script fragment at the very end of
InstallQemuFwCfgTables().
Cc: Jordan Justen <jordan.l.justen@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=359
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Laszlo Ersek