linux-kernel - Re: efi_enabled(EFI

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20160430204420.GM2839@codeblueprint.co.uk>
Date:	Sat, 30 Apr 2016 21:44:20 +0100
From:	Matt Fleming <matt@...eblueprint.co.uk>
To:	Shannon Zhao <shannon.zhao@...aro.org>
Cc:	Ard Biesheuvel <ard.biesheuvel@...aro.org>,
	Stefano Stabellini <sstabellini@...nel.org>,
	Ingo Molnar <mingo@...nel.org>,
	Stephen Rothwell <sfr@...b.auug.org.au>,
	"Luis R. Rodriguez" <mcgrof@...nel.org>,
	Jeremy Fitzhardinge <jeremy@...p.org>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	Stefano Stabellini <stefano.stabellini@...citrix.com>,
	Xen Devel <Xen-devel@...ts.xensource.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...e.hu>, "H. Peter Anvin" <hpa@...or.com>,
	Peter Zijlstra <peterz@...radead.org>,
	linux-next@...r.kernel.org,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Borislav Petkov <bp@...en8.de>
Subject: Re: efi_enabled(EFI_PARAVIRT) use

On Sat, 30 Apr, at 10:14:42PM, Shannon Zhao wrote:
> Sure. How should I add this change? Rework this patch or add new one on
> top of it?
 
Rework this patch, please.

> Yes, in this patch we could set EFI_RUNTIME_SERVICES flag in
> fdt_find_hyper_node instead of setting EFI_PARAVIRT flag, and then bail
> out early in arm_enable_runtime_services() as you said. Then call
> xen_efi_runtime_setup() in xen_guest_init().
 
Sounds good.

> While I still have a question, in this patch we use
> efi_enabled(EFI_PARAVIRT) as a condition to make fdt_find_uefi_params()
> and efi_get_fdt_params() execute different ways. So it needs to find a
> new condition for that if we need to get rid of EFI_PARAVIRT. One I
> think is that xen_initial_domain() check. Is that fine?

Hmm... why do you actually need to check whether you're running on a
PV machine in fdt_find_uefi_params()? Can't you infer that from the DT
params you discover?

I could understand maybe only accepting the "xen,uefi-system-table"
property if IS_ENABLED(CONFIG_XEN) but surely you don't also need to
filter based on whether you're booting a PV kernel?

Let me put it this way: when would you see "xen,uefi-system-table" and
*not* be booting a PV kernel?