From: Matt Fleming <matt@codeblueprint.co.uk>
To: Borislav Petkov <bp@alien8.de>
Cc: 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>
Subject: Re: efi_enabled(EFI_PARAVIRT) use
Date: Fri, 29 Apr 2016 10:26:51 +0100 [thread overview]
Message-ID: <20160429092651.GD2839@codeblueprint.co.uk> (raw)
In-Reply-To: <20160429082501.GA20762@pd.tnic>
On Fri, 29 Apr, at 10:25:02AM, Borislav Petkov wrote:
> On Fri, Apr 29, 2016 at 08:39:36AM +0200, Ingo Molnar wrote:
> > With considerable pain we just got rid of paravirt_enabled() in the
> > x86 tree, and Xen is now reintroducing it in the EFI code.
>
> I think Matt is working towards removing EFI_PARAVIRT but he'll comment
> himself when he wakes up... :)
Yeah, I haven't actually got around to dropping EFI_PARAVIRT yet but
since it's basically used to skip certain initialisation operations on
boot I figured we could just provide empty stub functions as part of
struct efi (probably).
The concerns Ingo voiced about EFI_PARAVIRT being a catch-all flag are
very true.
Incidentally kexec and arm64 would need a similar stub functions if we
move more EFI runtime setup code to drivers/firmware/efi, which is my
long-term plan, since neither can call SetVirtualAddressMap().
On x86, I think EFI_PARAVIRT is code for,
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
1. and 2. should be covered by never setting EFI_MEMMAP and
EFI_RUNTIME_SERVICES in efi.flags. We have no bits for 3. and 4. yet.
next prev parent reply other threads:[~2016-04-29 9:26 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 [this message]
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
2016-04-29 15:37 ` Stefano Stabellini
2016-04-30 14:04 ` Shannon Zhao
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