From mboxrd@z Thu Jan 1 00:00:00 1970 From: shannon.zhao@linaro.org (Shannon Zhao) Date: Tue, 19 Jan 2016 21:43:59 +0800 Subject: [PATCH v2 12/16] ARM: Xen: Document UEFI support on Xen ARM virtual platforms In-Reply-To: <20160119131348.GJ25024@leverpostej> References: <1452840929-19612-1-git-send-email-zhaoshenglong@huawei.com> <1452840929-19612-13-git-send-email-zhaoshenglong@huawei.com> <20160118105115.GD21067@leverpostej> <569E0F15.8090001@huawei.com> <20160119104747.GB25024@leverpostej> <20160119131348.GJ25024@leverpostej> Message-ID: <569E3D9F.6050808@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 2016/1/19 21:13, Mark Rutland wrote: > On Tue, Jan 19, 2016 at 12:23:17PM +0000, Stefano Stabellini wrote: >> >On Tue, 19 Jan 2016, Mark Rutland wrote: >>> > >On Tue, Jan 19, 2016 at 06:25:25PM +0800, Shannon Zhao wrote: >>>>>> > > > >>We don't do this in Documentation/arm/uefi.txt, and I don't see why we >>>>>> > > > >>should do so here. >>>>>> > > > >> >>>>>> > > > >>Does Xen handle arbitrary size memory map descriptors? I'm not sure what >>>>>> > > > >>new information might be passed in future additions to the descriptor >>>>>> > > > >>format, and I'm not sure what should happen in the Dom0 case. >>>>> > > > > >>>>> > > > >Xen passes to Dom0 the memory map in the same format as the native >>>>> > > > >memory map. >>> > > >>> > >Does Xen parse or modify the EFI memory map in any way? >> > >> >Xen: >> >- calls EFI_BOOT_SERVICES.GetMemoryMap() >> >- takes note of the memory regions for its own usage >> >- create the fdt notes, including efi-mmap-start, with a pointer to it >> > >> > >>> > >Does it pass the raw values returned by EFI_BOOT_SERVICES.GetMemoryMap() >>> > >through to the xen,uefi-* properties, or does is make any static >>> > >assumptions about what the values will be? >> > >> >It just passes the raw values. > I take it that means that any memory carved out for Xen itself is > described/discovered via a separate mechanism? How does that work For Xen hypervisor booting on UEFI, it get the EFI memory map through the similar way like Linux, e.g. call EFI_BOOT_SERVICES.GetMemoryMap(). For Dom0, Xen will create a new EFI memory map for Dom0. See [PATCH v3 52/62] arm/acpi: Prepare EFI memory descriptor for Dom0 http://lists.xen.org/archives/html/xen-devel/2015-11/msg01884.html Thanks, -- Shannon