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From: Mark Rutland <mark.rutland@arm.com>
To: Will Deacon <will.deacon@arm.com>
Cc: devicetree@vger.kernel.org, linux-efi@vger.kernel.org,
	catalin.marinas@arm.com, linux-kernel@vger.kernel.org,
	peter.huangpeng@huawei.com, julien.grall@arm.com,
	stefano.stabellini@citrix.com,
	Shannon Zhao <shannon.zhao@linaro.org>,
	zhaoshenglong@huawei.com, xen-devel@lists.xen.org,
	linux-arm-kernel@lists.infradead.org, david.vrabel@citrix.com
Subject: Re: [PATCH v7 12/17] ARM64: ACPI: Check if it runs on Xen to enable or disable ACPI
Date: Tue, 29 Mar 2016 17:31:47 +0100	[thread overview]
Message-ID: <20160329163147.GB27223__28192.7664801062$1459269192$gmane$org@leverpostej> (raw)
In-Reply-To: <20160329161837.GH6745@arm.com>

On Tue, Mar 29, 2016 at 05:18:38PM +0100, Will Deacon wrote:
> On Thu, Mar 24, 2016 at 10:44:31PM +0800, Shannon Zhao wrote:
> > When it's a Xen domain0 booting with ACPI, it will supply a /chosen and
> > a /hypervisor node in DT. So check if it needs to enable ACPI.
> > 
> > Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
> > Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> > Acked-by: Hanjun Guo <hanjun.guo@linaro.org>
> > ---
> >  arch/arm64/kernel/acpi.c | 12 ++++++++----
> >  1 file changed, 8 insertions(+), 4 deletions(-)
> > 
> > diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
> > index d1ce8e2..4e92be0 100644
> > --- a/arch/arm64/kernel/acpi.c
> > +++ b/arch/arm64/kernel/acpi.c
> > @@ -67,10 +67,13 @@ static int __init dt_scan_depth1_nodes(unsigned long node,
> >  {
> >  	/*
> >  	 * Return 1 as soon as we encounter a node at depth 1 that is
> > -	 * not the /chosen node.
> > +	 * not the /chosen node, or /hypervisor node when running on Xen.
> >  	 */
> > -	if (depth == 1 && (strcmp(uname, "chosen") != 0))
> > -		return 1;
> > +	if (depth == 1 && (strcmp(uname, "chosen") != 0)) {
> > +		if (!xen_initial_domain() || (strcmp(uname, "hypervisor") != 0))
> > +			return 1;
> > +	}
> 
> Hmm, but xen_initial_domain() is false when xen isn't being used at all,
> so it feels to me like this is a bit too far-reaching and is basically
> claiming the "/hypervisor" namespace for Xen. Couldn't it be renamed to
> "xen,hypervisor" or something?
> 
> Mark, got any thoughts on this?

The node has a compatible string, "xen,xen" per [1], which would tell us
absolutely that xen is present. I'd be happy checking for that
explicitly.

In patch 11 fdt_find_hyper_node checks the compatible string. We could
factor that out into a helper like is_xen_node(node) and use it here
too.

If in future we want to do the same for other hypervisors we can add
explicit checks for their compatible strings and/or wrap that in a more
generic helper to cater for any hypervisor-specific details.

Thanks,
Mark.

[1] Documentation/devicetree/bindings/arm/xen.txt

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  parent reply	other threads:[~2016-03-29 16:31 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1458830676-27075-1-git-send-email-shannon.zhao@linaro.org>
2016-03-24 14:44 ` [PATCH v7 01/17] Xen: ACPI: Hide UART used by Xen Shannon Zhao
2016-03-24 14:44 ` [PATCH v7 02/17] xen/grant-table: Move xlated_setup_gnttab_pages to common place Shannon Zhao
2016-03-24 14:44 ` [PATCH v7 03/17] Xen: xlate: Use page_to_xen_pfn instead of page_to_pfn Shannon Zhao
2016-03-29 16:28   ` Julien Grall
     [not found]   ` <56FAAD48.2010401@arm.com>
2016-03-30  7:38     ` Shannon Zhao
     [not found]     ` <56FB8258.7030303@huawei.com>
2016-03-30 11:22       ` Julien Grall
     [not found]       ` <56FBB709.5050802@arm.com>
2016-03-30 12:42         ` Shannon Zhao
2016-03-24 14:44 ` [PATCH v7 04/17] arm/xen: Use xen_xlate_map_ballooned_pages to setup grant table Shannon Zhao
2016-03-24 14:44 ` [PATCH v7 05/17] xen: memory : Add new XENMAPSPACE type XENMAPSPACE_dev_mmio Shannon Zhao
2016-03-24 14:44 ` [PATCH v7 06/17] Xen: ARM: Add support for mapping platform device mmio Shannon Zhao
2016-03-24 14:44 ` [PATCH v7 07/17] Xen: ARM: Add support for mapping AMBA " Shannon Zhao
2016-03-24 14:44 ` [PATCH v7 08/17] Xen: public/hvm: sync changes of HVM_PARAM_CALLBACK_VIA ABI from Xen Shannon Zhao
2016-03-24 14:44 ` [PATCH v7 09/17] xen/hvm/params: Add a new delivery type for event-channel in HVM_PARAM_CALLBACK_IRQ Shannon Zhao
2016-03-24 14:44 ` [PATCH v7 10/17] arm/xen: Get event-channel irq through HVM_PARAM when booting with ACPI Shannon Zhao
2016-03-29 16:35   ` Julien Grall
     [not found]   ` <56FAAEED.7060108@arm.com>
2016-03-30  7:34     ` Shannon Zhao
2016-03-24 14:44 ` [PATCH v7 11/17] ARM: XEN: Move xen_early_init() before efi_init() Shannon Zhao
2016-03-24 14:44 ` [PATCH v7 12/17] ARM64: ACPI: Check if it runs on Xen to enable or disable ACPI Shannon Zhao
2016-03-24 14:44 ` [PATCH v7 13/17] ARM: Xen: Document UEFI support on Xen ARM virtual platforms Shannon Zhao
2016-03-24 14:44 ` [PATCH v7 14/17] XEN: EFI: Move x86 specific codes to architecture directory Shannon Zhao
2016-03-24 14:44 ` [PATCH v7 15/17] ARM64: XEN: Add a function to initialize Xen specific UEFI runtime services Shannon Zhao
2016-03-24 14:44 ` [PATCH v7 16/17] FDT: Add a helper to get the subnode by given name Shannon Zhao
2016-03-24 14:44 ` [PATCH v7 17/17] Xen: EFI: Parse DT parameters for Xen specific UEFI Shannon Zhao
     [not found] ` <1458830676-27075-2-git-send-email-shannon.zhao@linaro.org>
2016-03-24 15:08   ` [PATCH v7 01/17] Xen: ACPI: Hide UART used by Xen Rafael J. Wysocki
     [not found]   ` <CAJZ5v0iGHj1Hb3s=uJ34j0m88+3xtBQhbX47got=z1Ah_=LrkQ@mail.gmail.com>
2016-03-25  7:38     ` Shannon Zhao
2016-03-25  8:05   ` [PATCH v8 " Shannon Zhao
     [not found]   ` <1458893149-17388-1-git-send-email-zhaoshenglong@huawei.com>
2016-03-25 17:00     ` Rafael J. Wysocki
2016-03-25 17:15     ` Bjorn Helgaas
     [not found]     ` <7418231.W9aSFKr1zs@vostro.rjw.lan>
2016-03-26 13:14       ` Stefano Stabellini
     [not found]     ` <20160325171547.GB29822@localhost>
2016-03-26 12:44       ` Stefano Stabellini
2016-03-29  8:00       ` Shannon Zhao
2016-03-29  8:08     ` [RESEND PATCH v9 " Shannon Zhao
     [not found] ` <1458830676-27075-12-git-send-email-shannon.zhao@linaro.org>
2016-03-26 12:54   ` [PATCH v7 11/17] ARM: XEN: Move xen_early_init() before efi_init() Stefano Stabellini
     [not found]   ` <alpine.DEB.2.02.1603261252510.18380@kaball.uk.xensource.com>
2016-03-29 16:07     ` Will Deacon
     [not found]     ` <20160329160756.GG6745@arm.com>
2016-03-31 11:12       ` Stefano Stabellini
     [not found] ` <1458830676-27075-13-git-send-email-shannon.zhao@linaro.org>
2016-03-26 12:56   ` [PATCH v7 12/17] ARM64: ACPI: Check if it runs on Xen to enable or disable ACPI Stefano Stabellini
2016-03-29 16:18   ` Will Deacon
     [not found]   ` <20160329161837.GH6745@arm.com>
2016-03-29 16:31     ` Mark Rutland [this message]
     [not found]     ` <20160329163147.GB27223@leverpostej>
2016-03-30  7:19       ` Shannon Zhao
     [not found]       ` <56FB7E00.7030400@huawei.com>
2016-03-31 11:04         ` Stefano Stabellini
     [not found]         ` <alpine.DEB.2.02.1603311155450.11739@kaball.uk.xensource.com>
2016-03-31 11:44           ` Ard Biesheuvel
     [not found]           ` <CAKv+Gu-wPq_FzO3sm7bhSFuu7EVxHWB_v6HOn1GqNbdaE-iBoQ@mail.gmail.com>
2016-03-31 12:42             ` Mark Rutland
     [not found]             ` <20160331124216.GE26532@leverpostej>
2016-04-01  9:25               ` Shannon Zhao
     [not found]               ` <56FE3E85.60403@huawei.com>
2016-04-01  9:32                 ` Shannon Zhao
     [not found] ` <1458830676-27075-14-git-send-email-shannon.zhao@linaro.org>
2016-03-29 17:21   ` [PATCH v7 13/17] ARM: Xen: Document UEFI support on Xen ARM virtual platforms Julien Grall
     [not found] <20160331144418.GR27408@perard.uk.xensource.com>
2016-03-31 15:21 ` [PATCH v7 12/17] ARM64: ACPI: Check if it runs on Xen to enable or disable ACPI Stefano Stabellini

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