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Re: [Qemu-devel] [PULL 15/54] build: convert pci.mak to Kconfig


From: Paolo Bonzini
Subject: Re: [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



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