Re: [Xen-devel] efi_enabled(EFI_PARAVIRT) use

From: Shannon Zhao <zhaoshenglong@huawei.com>
To: Shannon Zhao <shannon.zhao@linaro.org>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Matt Fleming <matt@codeblueprint.co.uk>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>,
	Jeremy Fitzhardinge <jeremy@goop.org>,
	Stefano Stabellini <sstabellini@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Luis R. Rodriguez" <mcgrof@kernel.org>,
	Xen Devel <Xen-devel@lists.xensource.com>,
	Borislav Petkov <bp@alien8.de>,
	linux-next@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@kernel.org>
Subject: Re: [Xen-devel] efi_enabled(EFI_PARAVIRT) use
Date: Tue, 3 May 2016 17:13:52 +0800	[thread overview]
Message-ID: <57286BD0.2000809@huawei.com> (raw)
In-Reply-To: <5724BDD2.5020600@linaro.org>

On 2016/4/30 22:14, Shannon Zhao wrote:
>> I already proposed when this patch was first under review to make the
>> > arm_enable_runtime_services() function bail early without error if the
>> > EFI_RUNTIME_SERVICES flag is already set, and the xen code could set
>> > that bit as well when it installs its paravirtualized alternatives. I
>> > don't remember exactly why that was shot down, though, but I think it
>> > is the only reason this code introduces references to EFI_PARAVIRT in
>> > the first place.
>> > 
> 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().

Hi Ard,

If it sets EFI_RUNTIME_SERVICES flag in fdt_find_hyper_node and in
arm_enable_runtime_services() it checks whether it's a Dom0 through
xen_init_domain() and the EFI_RUNTIME_SERVICES flag is set, then call
xen_efi_runtime_setup(). Is it ok?

Thanks,
-- 
Shannon