Messages in this thread | | | Subject | Re: [PATCH V3 6/6] dt-bindings: xen: Clarify "reg" purpose | From | Oleksandr <> | Date | Thu, 25 Nov 2021 14:21:36 +0200 |
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On 25.11.21 03:09, Stefano Stabellini wrote:
Hi Stefano
> On Wed, 24 Nov 2021, Oleksandr Tyshchenko wrote: >> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> >> >> Xen on Arm has gained new support recently to calculate and report >> extended regions (unused address space) safe to use for external >> mappings. These regions are reported via "reg" property under >> "hypervisor" node in the guest device-tree. As region 0 is reserved >> for grant table space (always present), the indexes for extended >> regions are 1...N. >> >> No device-tree bindings update is needed (except clarifying the text) >> as guest infers the presence of extended regions from the number >> of regions in "reg" property. >> >> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> >> --- >> According to the recent update to Xen's guest.txt: >> https://xenbits.xen.org/gitweb/?p=xen.git;a=blob_plain;f=docs/misc/arm/device-tree/guest.txt;hb=refs/heads/master >> >> Changes V2 -> V3: >> - new patch >> --- >> Documentation/devicetree/bindings/arm/xen.txt | 12 ++++++++---- >> 1 file changed, 8 insertions(+), 4 deletions(-) >> >> diff --git a/Documentation/devicetree/bindings/arm/xen.txt b/Documentation/devicetree/bindings/arm/xen.txt >> index db5c56d..156fe10b 100644 >> --- a/Documentation/devicetree/bindings/arm/xen.txt >> +++ b/Documentation/devicetree/bindings/arm/xen.txt >> @@ -7,10 +7,14 @@ the following properties: >> compatible = "xen,xen-<version>", "xen,xen"; >> where <version> is the version of the Xen ABI of the platform. >> >> -- reg: specifies the base physical address and size of a region in >> - memory where the grant table should be mapped to, using an >> - HYPERVISOR_memory_op hypercall. The memory region is large enough to map >> - the whole grant table (it is larger or equal to gnttab_max_grant_frames()). >> +- reg: specifies the base physical address and size of the regions in memory >> + where the special resources should be mapped to, using an HYPERVISOR_memory_op >> + hypercall. >> + Region 0 is reserved for mapping grant table, it must be always present. >> + The memory region is large enough to map the whole grant table (it is larger >> + or equal to gnttab_max_grant_frames()). >> + Regions 1...N are extended regions (unused address space) for mapping foreign >> + GFNs and grants, they might be absent if there is nothing to expose. >> This property is unnecessary when booting Dom0 using ACPI. > I would remove the last sentence about ACPI as the initialization is not > done via the xen,xen device tree node in that case anyway.
Agree, will do. I assume, the similar sentence for the "interrupts" property down the text wants removing as well.
> > With that change: > > Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Thanks!
-- Regards,
Oleksandr Tyshchenko
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