From: Stefano Stabellini <sstabellini@kernel.org>
To: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
"Luis R. Rodriguez" <mcgrof@kernel.org>,
Jeremy Fitzhardinge <jeremy@goop.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
Xen Devel <Xen-devel@lists.xensource.com>,
Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
"H. Peter Anvin" <hpa@zytor.com>,
Peter Zijlstra <peterz@infradead.org>,
linux-next@vger.kernel.org, linux-kernel@vger.kernel.org,
Shannon Zhao <shannon.zhao@linaro.org>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Borislav Petkov <bp@alien8.de>
Subject: Re: efi_enabled(EFI_PARAVIRT) use
Date: Fri, 29 Apr 2016 15:58:47 +0100 (BST) [thread overview]
Message-ID: <alpine.DEB.2.10.1604291547130.3312@sstabellini-ThinkPad-X260> (raw)
In-Reply-To: <20160429143931.GG2839@codeblueprint.co.uk>
On Fri, 29 Apr 2016, Matt Fleming wrote:
> On Fri, 29 Apr, at 11:34:45AM, Stefano Stabellini wrote:
> > On Fri, 29 Apr 2016, Ingo Molnar wrote:
> > > Also, it would be nice to have all things EFI in a single tree, the conflicts are
> > > going to be painful! There's very little reason not to carry this kind of commit:
> > >
> > > arch/arm/xen/enlighten.c | 6 +++++
> > > drivers/firmware/efi/arm-runtime.c | 17 +++++++++-----
> > > drivers/firmware/efi/efi.c | 45 ++++++++++++++++++++++++++++++++------
> > > 3 files changed, 56 insertions(+), 12 deletions(-)
> > >
> > > in the EFI tree.
> >
> > That's true. I'll drop this commit from xentip and let Matt pick it up
> > or request changes as he sees fit.
>
> One small change I think would be sensible to make is to expand
> EFI_PARAVIRT into a few more bits to clearly indicate the quirks on
> Xen, and in the process, to delete EFI_PARAVIRT.
>
> That should address Ingo's major concern, and also make it much easier
> to rework the code in a piecemeal fashion.
>
> Could somebody enumerate the things that make Xen (dom0) different on
> arm* compared with bare metal EFI boot? The list I made for x86 was,
>
> 1. Has no EFI memory map
> 2. Runtime regions do not need to be mapped
> 3. Cannot call SetVirtualAddressMap()
> 4. /sys/firmware/efi/fw_vendor is invisible
>
> The first maps to not setting EFI_MEMMAP, the second to not setting
> EFI_RUNTIME. If we add EFI_ALREADY_VIRTUAL and EFI_FW_VENDOR_INVISIBLE
> to efi.flags that should cover everything on x86. Does arm* require
> anything else?
Xen on ARM is different, the impact should be limited:
- there are no BootServices (ExitBootServices has already been called)
- RuntimeServices go via hypercalls
The UEFI memory map is still available at an address specified on device
tree like on native, but the compatibility string is different
("xen,uefi-mmap-start") to clarify that we are booting on Xen rather
than native.
That's pretty much it, Shannon please confirm.
next prev parent reply other threads:[~2016-04-29 14:58 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-29 4:20 linux-next: manual merge of the xen-tip tree with the tip tree Stephen Rothwell
2016-04-29 6:39 ` efi_enabled(EFI_PARAVIRT) use Ingo Molnar
2016-04-29 8:25 ` Borislav Petkov
2016-04-29 9:26 ` Matt Fleming
2016-04-29 10:34 ` Stefano Stabellini
2016-04-29 10:46 ` Ingo Molnar
2016-04-29 14:39 ` Matt Fleming
2016-04-29 14:53 ` Ard Biesheuvel
2016-04-30 14:14 ` Shannon Zhao
2016-04-30 20:44 ` Matt Fleming
2016-05-01 3:24 ` Shannon Zhao
2016-05-01 13:26 ` Matt Fleming
2016-05-01 14:36 ` Shannon Zhao
2016-05-02 10:45 ` Matt Fleming
2016-05-03 1:45 ` [Xen-devel] " Shannon Zhao
2016-05-04 11:36 ` Matt Fleming
2016-05-03 9:13 ` Shannon Zhao
2016-04-29 14:58 ` Stefano Stabellini [this message]
2016-04-29 15:37 ` Stefano Stabellini
2016-04-30 14:04 ` Shannon Zhao
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