From: "Gerd Hoffmann" <kraxel@redhat.com>
To: "Boeuf, Sebastien" <sebastien.boeuf@intel.com>
Cc: "Yao, Jiewen" <jiewen.yao@intel.com>,
"Justen, Jordan L" <jordan.l.justen@intel.com>,
"devel@edk2.groups.io" <devel@edk2.groups.io>,
"ardb+tianocore@kernel.org" <ardb+tianocore@kernel.org>
Subject: Re: [OVMF] What would be the best way to make PcdPciMmio64Size dynamic?
Date: Tue, 17 Jan 2023 15:38:18 +0100 [thread overview]
Message-ID: <20230117143818.oy5fer3sgt23hljh@sirius.home.kraxel.org> (raw)
In-Reply-To: <3f999b7791ac4c1ccbd73a65e5c3635d21b6d84d.camel@intel.com>
On Tue, Jan 17, 2023 at 02:10:08PM +0000, Boeuf, Sebastien wrote:
> Hi,
>
> Looking at the hardcoded limitation provided by PcdPciMmio64Size
> (32GiB), I was wondering what would be the best approach to make this a
> bit more dynamic?
>
> I know that for QEMU, the fw_cfg mechanism can be used to override the
> value of PcdPciMmio64Size, but this isn't something Cloud Hypervisor or
> other VMMs can implement given they don't support fw_cfg at all.
>
> Would it be acceptable to dynamically compute PcdPciMmio64Size from the
> physical address space? Given the reason why PcdPciMmio64Size can't be
> increased is to make sure it can support host with small address space
> (such as 36 bits), we could introduce a very simple function that would
> determine the available address space and consider PcdPciMmio64Size
> being half the size.
Sure, check master branch, the code is already there. Should just be a
matter of wiring up the function calls for cloundhv, and you can
probably call PlatformAddressWidthFromCpuid() with QemuQuirk = false
unconditionally.
take care,
Gerd
next prev parent reply other threads:[~2023-01-17 14:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-17 14:10 [OVMF] What would be the best way to make PcdPciMmio64Size dynamic? Boeuf, Sebastien
2023-01-17 14:38 ` Gerd Hoffmann [this message]
2023-01-18 14:24 ` Boeuf, Sebastien
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