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| author | Laszlo Ersek <lersek@redhat.com> | 2016-03-08 13:01:03 +0100 |
|---|---|---|
| committer | Laszlo Ersek <lersek@redhat.com> | 2016-03-10 21:28:07 +0100 |
| commit | b01acf6ea7e729a690ff6aa926a5ea20611eb117 (patch) | |
| tree | b6eefbd3f2de43c7d1c336c8b0e16531cc9a261e /OvmfPkg/PlatformPei | |
| parent | 0aff49e20fe0630c0c1b727608373a3314b62c7d (diff) | |
| download | edk2-b01acf6ea7e729a690ff6aa926a5ea20611eb117.tar.gz edk2-b01acf6ea7e729a690ff6aa926a5ea20611eb117.tar.bz2 edk2-b01acf6ea7e729a690ff6aa926a5ea20611eb117.zip | |
OvmfPkg: PlatformPei: lower the 32-bit PCI MMIO base to 2GB on Q35
Gerd has advised us that long term support Q35 machine types have no low
RAM above 2GB, hence we should utilize the [2GB, 3GB) gap -- that we
currently leave unused -- for MMIO. (Plus, later in this series, for the
PCIEXBAR too.)
Cc: Gabriel Somlo <somlo@cmu.edu>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Marcel Apfelbaum <marcel@redhat.com>
Cc: Michał Zegan <webczat_200@poczta.onet.pl>
Ref: https://github.com/tianocore/edk2/issues/32
Ref: http://thread.gmane.org/gmane.comp.bios.edk2.devel/8707/focus=8817
Suggested-by: Gerd Hoffmann <kraxel@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Gabriel Somlo <somlo@cmu.edu>
Tested-by: Michał Zegan <webczat_200@poczta.onet.pl>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Diffstat (limited to 'OvmfPkg/PlatformPei')
| -rw-r--r-- | OvmfPkg/PlatformPei/Platform.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/OvmfPkg/PlatformPei/Platform.c b/OvmfPkg/PlatformPei/Platform.c index 7d0941209f..8e4da41001 100644 --- a/OvmfPkg/PlatformPei/Platform.c +++ b/OvmfPkg/PlatformPei/Platform.c @@ -218,11 +218,10 @@ MemMapInitialization ( TopOfLowRam = GetSystemMemorySizeBelow4gb ();
if (mHostBridgeDevId == INTEL_Q35_MCH_DEVICE_ID) {
//
- // A 3GB base will always fall into Q35's 32-bit PCI host aperture,
- // regardless of the Q35 MMCONFIG BAR. Correspondingly, QEMU never lets
- // the RAM below 4 GB exceed it.
+ // On Q35 machine types that QEMU intends to support in the long term,
+ // QEMU never lets the RAM below 4 GB exceed 2 GB.
//
- PciBase = BASE_2GB + BASE_1GB;
+ PciBase = BASE_2GB;
ASSERT (TopOfLowRam <= PciBase);
} else {
PciBase = (TopOfLowRam < BASE_2GB) ? BASE_2GB : TopOfLowRam;
|