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Re: [Qemu-riscv] [Qemu-devel] [PULL 15/54] build: convert pci.mak to Kco
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-riscv] [Qemu-devel] [PULL 15/54] build: convert pci.mak to Kconfig |
Date: |
Thu, 14 Mar 2019 18:34:19 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 |
On 14/03/19 14:03, David Abdurachmanov wrote:
> Would it be enough to modify ./default-configs/riscv32-softmmu.mak by
> adding:
>
> CONFIG_PCIE_PORT=n
The missing dependency is for any board that doesn't support MSI, not
just RISC-V.
Note that technically what we do with msi_nonbroken makes no sense from
the PCI point of view. An "MSI" is just a memory write so there is no
such thing as a device that doesn't work because the board doesn't
support MSI; it should be up to the OS not to configure MSI unless it
knows the interrupt controller can be set up as a destination for MSIs.
The driver in the OS then can choose to use level-triggered interrupts
(INTX) instead, or it can refuse to load. At least, this is how QEMU
*should* work.
However, we started doing this msi_nonbroken thing, and therefore, since
we can model it correctly with Kconfig and obtain the same results as
pre-Kconfig, it's a better way to do it.
Paolo