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From: Peter Maydell <peter.maydell@linaro.org>
To: Alistair Francis <alistair23@gmail.com>
Cc: "open list:RISC-V" <qemu-riscv@nongnu.org>,
	Palmer Dabbelt <palmer@sifive.com>,
	"qemu-devel@nongnu.org Developers" <qemu-devel@nongnu.org>,
	Markus Armbruster <armbru@redhat.com>,
	Alistair Francis <alistair.francis@wdc.com>,
	Bin Meng <bmeng.cn@gmail.com>
Subject: Re: [PATCH v1 5/6] riscv/virt: Add the PFlash CFI01 device
Date: Mon, 23 Sep 2019 22:46:17 +0100	[thread overview]
Message-ID: <CAFEAcA-uFPGf4BiDXH=Om3Df-xXrt7QwjzVF7E3kY4aMWMP4YQ@mail.gmail.com> (raw)
In-Reply-To: <CAKmqyKOofA3U+8kjMkzQ0sNd1=uwJHq3c9eaLZdoNCb7=e-PAw@mail.gmail.com>

On Fri, 20 Sep 2019 at 23:23, Alistair Francis <alistair23@gmail.com> wrote:
> On Thu, Sep 19, 2019 at 10:15 PM Bin Meng <bmeng.cn@gmail.com> wrote:
> > I don't think we should mirror what is used on ARM virt board to
> > create 2 flash for sifive_u. For ARM virt, there are 2 flashes because
> > they need distinguish secure and non-secure. For sifive_u, only one is
> > enough.
>
> I went back and forward about 1 or 2. Two seems more usable as maybe
> someone wants to include two pflash files? The Xilinx machine also has
> two so I'm kind of used to 2, but I'm not really fussed.

One of the reasons for having 2 on the Arm board (we do this
even if we're not supporting secure vs non-secure) is that
then you can use one for a fixed read-only BIOS image (backed
by a file on the host filesystem shared between all VMs), and
one backed by a read-write per-VM file providing permanent
storage for BIOS environment variables. Notably UEFI likes to
work this way, but the idea applies in theory to other
boot loader or BIOSes I guess.

I would suggest also checking with Markus that your code
for instantiating the flash devices follows the current
recommendations so the backing storage can be configured
via -blockdev. (This is a fairly recent change from June or
so; current-in-master virt and sbsa boards provide an example
of doing the right thing, I think.)

thanks
-- PMM


  parent reply	other threads:[~2019-09-23 22:24 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-19 22:24 [PATCH v1 0/6] RISC-V: Add more machine memory Alistair Francis
2019-09-19 22:24 ` [PATCH v1 1/6] riscv/sifive_u: Add L2-LIM cache memory Alistair Francis
2019-09-20  5:15   ` Bin Meng
2019-09-19 22:24 ` [PATCH v1 2/6] riscv/sifive_u: Add QSPI memory region Alistair Francis
2019-09-20  5:15   ` Bin Meng
2019-09-19 22:25 ` [PATCH v1 3/6] riscv/sifive_u: Manually define the machine Alistair Francis
2019-09-20  5:15   ` Bin Meng
2019-09-19 22:25 ` [PATCH v1 4/6] riscv/sifive_u: Add the start-in-flash property Alistair Francis
2019-09-20  5:15   ` Bin Meng
2019-09-20 22:07     ` Alistair Francis
2019-09-22  2:19       ` Bin Meng
2019-09-23 17:51         ` Alistair Francis
2019-09-24  0:57           ` Bin Meng
2019-09-19 22:25 ` [PATCH v1 5/6] riscv/virt: Add the PFlash CFI01 device Alistair Francis
2019-09-20  5:15   ` Bin Meng
2019-09-20 22:12     ` Alistair Francis
2019-09-22  2:15       ` Bin Meng
2019-09-23 20:08         ` Alistair Francis
2019-09-23 21:46       ` Peter Maydell [this message]
2019-09-24  9:32         ` Philippe Mathieu-Daudé
2019-09-24 17:12           ` Laszlo Ersek
2019-09-25  0:55           ` Alistair Francis
2019-09-25 11:15             ` Philippe Mathieu-Daudé
2019-09-25  0:54         ` Alistair Francis
2019-09-25  9:00           ` Markus Armbruster
2019-09-27 21:49             ` Alistair Francis
2019-09-19 22:25 ` [PATCH v1 6/6] riscv/virt: Jump to pflash if specified Alistair Francis
2019-09-20  5:15   ` Bin Meng
2019-09-23  9:09     ` Philippe Mathieu-Daudé
2019-09-20 22:40 ` [PATCH v1 0/6] RISC-V: Add more machine memory Palmer Dabbelt

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