From: Laszlo Ersek <lersek@redhat.com>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
edk2-devel@ml01.01.org, leif.lindholm@linaro.org
Subject: Re: [PATCH 0/3] ArmPkg ArmVirtPkg: prevent 64-bit MMIO BAR degradation
Date: Mon, 12 Sep 2016 13:57:00 +0200 [thread overview]
Message-ID: <9e187728-7127-d665-16e8-3b661571e3a3@redhat.com> (raw)
In-Reply-To: <1473674479-20207-1-git-send-email-ard.biesheuvel@linaro.org>
On 09/12/16 12:01, Ard Biesheuvel wrote:
> On ARM/Linux systems, the PCI layer is usually reconfigured from scratch,
> given the embedded legacy of ARM systems. However, when booting arm64/Linux
> in ACPI mode, such reconfiguration can be avoided, since ACPI implies UEFI
> implies firmware (as opposed to DT mode, which could be booted via QEMU's
> ~10 instruction bootloader)
>
> In this case, it is important for the firmware to leave the PCI configuration
> in a reasonable state, and one of the things that UEFI does by default, and
> which makes no sense at all on an arm64 system, is to degrade 64-bit MMIO BARs
> to 32-bit in the presence of a ROM BAR on the same device. (It does makes sense
> on an Intel system running legacy option ROMs under a CSM)
>
> Fortunately, we have a way of influencing this policy without having to hack
> the generic PCI bus driver: we can install the IncompatiblePciDeviceSupport
> protocol, and the PCI bus driver will invoke it for each PCI device it
> configures.
>
> Our implementation for ArmPkg is simply the OVMF version with the bits ripped
> out that care about CSMs and legacy BIOSes
>
> Ard Biesheuvel (3):
> ArmPkg: add driver to force 64-bit MMIO BARs to be allocated above 4
> GB
> ArmVirtPkg/FdtPciPcdProducerLib: add discovery of PcdPciMmio64Size
> ArmVirtPkg/ArmVirtQemu: add IncompatiblePciDeviceSupportDxe
>
> ArmPkg/Drivers/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.c | 223 ++++++++++++++++++++
> ArmPkg/Drivers/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.inf | 49 +++++
> ArmVirtPkg/ArmVirtQemu.dsc | 5 +
> ArmVirtPkg/ArmVirtQemuFvMain.fdf.inc | 1 +
> ArmVirtPkg/ArmVirtQemuKernel.dsc | 5 +
> ArmVirtPkg/Library/FdtPciPcdProducerLib/FdtPciPcdProducerLib.c | 31 +--
> ArmVirtPkg/Library/FdtPciPcdProducerLib/FdtPciPcdProducerLib.inf | 1 +
> 7 files changed, 302 insertions(+), 13 deletions(-)
> create mode 100644 ArmPkg/Drivers/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.c
> create mode 100644 ArmPkg/Drivers/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.inf
>
Formatting / reviewing the first patch with "--find-copies-harder" works
wonders, so I recommend that flag for similar future posts.
Series
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Thanks
Laszlo
next prev parent reply other threads:[~2016-09-12 11:57 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-12 10:01 [PATCH 0/3] ArmPkg ArmVirtPkg: prevent 64-bit MMIO BAR degradation Ard Biesheuvel
2016-09-12 10:01 ` [PATCH 1/3] ArmPkg: add driver to force 64-bit MMIO BARs to be allocated above 4 GB Ard Biesheuvel
2016-09-12 10:23 ` Leif Lindholm
2016-09-12 12:29 ` Laszlo Ersek
2016-09-12 13:06 ` Ard Biesheuvel
2016-09-12 10:01 ` [PATCH 2/3] ArmVirtPkg/FdtPciPcdProducerLib: add discovery of PcdPciMmio64Size Ard Biesheuvel
2016-09-12 10:01 ` [PATCH 3/3] ArmVirtPkg/ArmVirtQemu: add IncompatiblePciDeviceSupportDxe Ard Biesheuvel
2016-09-12 11:57 ` Laszlo Ersek [this message]
2016-09-26 12:54 ` [PATCH 0/3] ArmPkg ArmVirtPkg: prevent 64-bit MMIO BAR degradation Ard Biesheuvel
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