From eb4d62b0779c3a5766174e4373c95a8b6a967cb7 Mon Sep 17 00:00:00 2001 From: Laszlo Ersek Date: Wed, 29 May 2019 11:51:26 +0200 Subject: Revert "OvmfPkg/PlatformPei: reorder the 32-bit PCI window vs. the PCIEXBAR on q35" This reverts commit 75136b29541b0e093a51d2e2c2af8d19855c2b60. The original fix for triggered a bug / incorrect assumption in QEMU. QEMU assumes that the PCIEXBAR is below the 32-bit PCI window, not above it. When the firmware doesn't satisfy this assumption, QEMU generates an \_SB.PCI0._CRS object in the ACPI DSDT that does not reflect the firmware's 32-bit MMIO BAR assignments. This causes OSes to re-assign 32-bit MMIO BARs. Working around the problem in the firmware looks less problematic than fixing QEMU. Revert the original changes first, before implementing an alternative fix. Cc: Ard Biesheuvel Cc: Gerd Hoffmann Cc: Jordan Justen Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1859 Signed-off-by: Laszlo Ersek Reviewed-by: Philippe Mathieu-Daude Acked-by: Ard Biesheuvel --- OvmfPkg/PlatformPei/Platform.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'OvmfPkg/PlatformPei') diff --git a/OvmfPkg/PlatformPei/Platform.c b/OvmfPkg/PlatformPei/Platform.c index fd8eccaf3e..9c013613a1 100644 --- a/OvmfPkg/PlatformPei/Platform.c +++ b/OvmfPkg/PlatformPei/Platform.c @@ -184,13 +184,14 @@ MemMapInitialization ( PciBase = (TopOfLowRam < BASE_2GB) ? BASE_2GB : TopOfLowRam; if (mHostBridgeDevId == INTEL_Q35_MCH_DEVICE_ID) { // - // The 32-bit PCI host aperture is expected to fall between the top of - // low RAM and the base of the MMCONFIG area. + // The MMCONFIG area is expected to fall between the top of low RAM and + // the base of the 32-bit PCI host aperture. // PciExBarBase = FixedPcdGet64 (PcdPciExpressBaseAddress); - ASSERT (PciBase < PciExBarBase); + ASSERT (TopOfLowRam <= PciExBarBase); ASSERT (PciExBarBase <= MAX_UINT32 - SIZE_256MB); - PciSize = (UINT32)(PciExBarBase - PciBase); + PciBase = (UINT32)(PciExBarBase + SIZE_256MB); + PciSize = 0xFC000000 - PciBase; } else { PciSize = 0xFC000000 - PciBase; } -- cgit v1.2.3