[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v7 12/17] ARM64: ACPI: Check if it runs on Xen to enable or disable ACPI
Hi Will, Mark, On 2016/3/30 0:31, Mark Rutland wrote: > 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@xxxxxxxxxx> >>> > > Reviewed-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx> >>> > > Acked-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx> >>> > > --- >>> > > 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. > I think actually the xen_initial_domain is the result of the fdt_find_hyper_node. If the compatible string "xen,xen" doesn't exist, the xen_initial_domain() will return false and whatever the current node is the above check will return 1 since the device tree is not empty. > 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. > I don't think so because we already check the compatible string before and we could get the result simply via xen_initial_domain(). Thanks, -- Shannon _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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