[PATCH v3 13/17] ARM: Xen: Document UEFI support on Xen ARM virtual platforms
From: mark.rutland@arm.com (Mark Rutland)
Date: 2016-01-25 16:01:29
Also in:
linux-devicetree, linux-efi, lkml, xen-devel
On Mon, Jan 25, 2016 at 03:50:52PM +0000, Stefano Stabellini wrote:
On Sat, 23 Jan 2016, Shannon Zhao wrote:quoted
From: Shannon Zhao <redacted> Add a "uefi" node under /hypervisor node in FDT, then Linux kernel could scan this to get the UEFI information. Signed-off-by: Shannon Zhao <redacted> Acked-by: Rob Herring <robh@kernel.org> --- CC: Rob Herring <robh@kernel.org> --- Documentation/devicetree/bindings/arm/xen.txt | 34 +++++++++++++++++++++++++++ 1 file changed, 34 insertions(+)diff --git a/Documentation/devicetree/bindings/arm/xen.txt b/Documentation/devicetree/bindings/arm/xen.txt index 0f7b9c2..aa69405 100644 --- a/Documentation/devicetree/bindings/arm/xen.txt +++ b/Documentation/devicetree/bindings/arm/xen.txt@@ -15,6 +15,26 @@ the following properties: - interrupts: the interrupt used by Xen to inject event notifications. A GIC node is also required. +To support UEFI on Xen ARM virtual platforms, Xen populates the FDT "uefi" node +under /hypervisor with following parameters: + +________________________________________________________________________________ +Name | Size | Description +================================================================================ +xen,uefi-system-table | 64-bit | Guest physical address of the UEFI System + | | Table. +-------------------------------------------------------------------------------- +xen,uefi-mmap-start | 64-bit | Guest physical address of the UEFI memory + | | map. +-------------------------------------------------------------------------------- +xen,uefi-mmap-size | 32-bit | Size in bytes of the UEFI memory map + | | pointed to in previous entry. +-------------------------------------------------------------------------------- +xen,uefi-mmap-desc-size | 32-bit | Size in bytes of each entry in the UEFI + | | memory map. +-------------------------------------------------------------------------------- +xen,uefi-mmap-desc-ver | 32-bit | Version of the mmap descriptor format. +-------------------------------------------------------------------------------- Example (assuming #address-cells = <2> and #size-cells = <2>):@@ -22,4 +42,18 @@ hypervisor { compatible = "xen,xen-4.3", "xen,xen"; reg = <0 0xb0000000 0 0x20000>; interrupts = <1 15 0xf08>; + uefi { + xen,uefi-system-table = <0xXXXXXXXX>; + xen,uefi-mmap-start = <0xXXXXXXXX>; + xen,uefi-mmap-size = <0xXXXXXXXX>; + xen,uefi-mmap-desc-size = <0xXXXXXXXX>; + xen,uefi-mmap-desc-ver = <0xXXXXXXXX>; + }; }; + +The format and meaning of these "xen,uefi-*" parameters are similar to those in +Documentation/arm/uefi.txt which are used by normal UEFI. But to distinguish +from normal UEFI, for Xen ARM virtual platforms it needs to introduce a Xen +specific UEFI which requires Xen hypervisor to provide hypercalls for Dom0 to +make use of the runtime services. Therefore, it defines these parameters under +/hypervisor node.Please replace the paragraph with the following which mentions include/xen/interface/platform.h and improves the wording: "The format and meaning of the "xen,uefi-*" parameters are similar to those in Documentation/arm/uefi.txt, which are provided by the regular UEFI stub. However they differ because they are provided by the Xen hypervisor, together with a set of UEFI runtime services implemented via hypercalls, see include/xen/interface/platform.h."
I would prefer if we didn't refer to Linux paths here, for the usual rationale of keeping bindings distinct from Linux implementation details. Could we either drop the "see include/xen/interface/platform.h" part, or refer to some Xen documentation? Thanks, Mark.