On 2016年04月29日 22:53, Ard Biesheuvel wrote: > On 29 April 2016 at 16:39, Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx> wrote: >> On Fri, 29 Apr, at 11:34:45AM, Stefano Stabellini wrote: >>> On Fri, 29 Apr 2016, Ingo Molnar wrote: >>>> Also, it would be nice to have all things EFI in a single tree, the conflicts are >>>> going to be painful! There's very little reason not to carry this kind of commit: >>>> >>>> arch/arm/xen/enlighten.c | 6 +++++ >>>> drivers/firmware/efi/arm-runtime.c | 17 +++++++++----- >>>> drivers/firmware/efi/efi.c | 45 ++++++++++++++++++++++++++++++++------ >>>> 3 files changed, 56 insertions(+), 12 deletions(-) >>>> >>>> in the EFI tree. >>> >>> That's true. I'll drop this commit from xentip and let Matt pick it up >>> or request changes as he sees fit. >> >> One small change I think would be sensible to make is to expand >> EFI_PARAVIRT into a few more bits to clearly indicate the quirks on >> Xen, and in the process, to delete EFI_PARAVIRT. >> Sure. How should I add this change? Rework this patch or add new one on top of it? >> That should address Ingo's major concern, and also make it much easier >> to rework the code in a piecemeal fashion. >> >> Could somebody enumerate the things that make Xen (dom0) different on >> arm* compared with bare metal EFI boot? The list I made for x86 was, >> >> 1. Has no EFI memory map >> 2. Runtime regions do not need to be mapped >> 3. Cannot call SetVirtualAddressMap() >> 4. /sys/firmware/efi/fw_vendor is invisible >> >> The first maps to not setting EFI_MEMMAP, the second to not setting >> EFI_RUNTIME. If we add EFI_ALREADY_VIRTUAL and EFI_FW_VENDOR_INVISIBLE >> to efi.flags that should cover everything on x86. Does arm* require >> anything else? > > I already proposed when this patch was first under review to make the > arm_enable_runtime_services() function bail early without error if the > EFI_RUNTIME_SERVICES flag is already set, and the xen code could set > that bit as well when it installs its paravirtualized alternatives. I > don't remember exactly why that was shot down, though, but I think it > is the only reason this code introduces references to EFI_PARAVIRT in > the first place. > Yes, in this patch we could set EFI_RUNTIME_SERVICES flag in fdt_find_hyper_node instead of setting EFI_PARAVIRT flag, and then bail out early in arm_enable_runtime_services() as you said. Then call xen_efi_runtime_setup() in xen_guest_init(). While I still have a question, in this patch we use efi_enabled(EFI_PARAVIRT) as a condition to make fdt_find_uefi_params() and efi_get_fdt_params() execute different ways. So it needs to find a new condition for that if we need to get rid of EFI_PARAVIRT. One I think is that xen_initial_domain() check. Is that fine? Thanks, -- Shannon -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
