From: Shannon Zhao <shannon.zhao@linaro.org>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
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" <linux-kernel@vger.kernel.org>,
Borislav Petkov <bp@alien8.de>
Subject: Re: efi_enabled(EFI_PARAVIRT) use
Date: Sat, 30 Apr 2016 22:14:42 +0800 [thread overview]
Message-ID: <5724BDD2.5020600@linaro.org> (raw)
In-Reply-To: <CAKv+Gu_k45_r0mke6ELb3Pi05BnJiEMqweJRfsy7S55FzCpF7Q@mail.gmail.com>
On 2016年04月29日 22:53, Ard Biesheuvel wrote:
> On 29 April 2016 at 16:39, Matt Fleming <matt@codeblueprint.co.uk> 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.
>>
Sure. How should I add this change? Rework this patch or add new one on
top of it?
>> 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?
>
> 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().
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?
Thanks,
--
Shannon
next prev parent reply other threads:[~2016-04-30 14:14 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 [this message]
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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