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]
In preparation for introducing DxeResetSystemLib, rename the current
(only) ResetSystemLib instance to BaseResetSystemLib.
In the DSC files, keep the ResetSystemLib resolution in the same
[LibraryClasses] section, but move it near the TimerLib resolution, as the
differences between the ResetSystemLib instances will mostly follow those
seen under OvmfPkg/Library/AcpiTimerLib.
(While OvmfXen does not use "OvmfPkg/Library/AcpiTimerLib", perform the
same movement there too, for keeping future DSC diffing simple.)
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: <20200417153751.7110-6-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>
Laszlo Ersek