[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 16/16] ARM64: XEN: Initialize Xen specific UEFI runtime services
On 2016/1/19 21:03, Mark Rutland wrote: I think executing reset in Dom0 will reset not only Dom0 but also the Xen hypervisor, right?On Tue, Jan 19, 2016 at 12:03:59PM +0000, Stefano Stabellini wrote:On Mon, 18 Jan 2016, Mark Rutland wrote:On Mon, Jan 18, 2016 at 05:45:24PM +0000, Stefano Stabellini wrote:On Mon, 18 Jan 2016, Mark Rutland wrote:On Fri, Jan 15, 2016 at 02:55:29PM +0800, Shannon Zhao wrote:+void __init xen_efi_runtime_setup(void) +{ + efi.get_time = xen_efi_get_time; + efi.set_time = xen_efi_set_time; + efi.get_wakeup_time = xen_efi_get_wakeup_time; + efi.set_wakeup_time = xen_efi_set_wakeup_time; + efi.get_variable = xen_efi_get_variable; + efi.get_next_variable = xen_efi_get_next_variable; + efi.set_variable = xen_efi_set_variable; + efi.query_variable_info = xen_efi_query_variable_info; + efi.update_capsule = xen_efi_update_capsule; + efi.query_capsule_caps = xen_efi_query_capsule_caps; + efi.get_next_high_mono_count = xen_efi_get_next_high_mono_count; + efi.reset_system = NULL; +}How do capsules work in the absence of an EFI system reset?Actually I don't think that capsules are available in Xen on ARM64 yet, see "TODO - disabled until implemented on ARM" in xen/common/efi/runtime.c. FYI system reset is available, but it is provided via a different mechanism (HYPERVISOR_sched_op(xen_restart...)Will that trigger Xen to do the right thing to trigger capsule updates when implemented in Xen? Or do we need a xen_efi_reset_system?On ARM, to reboot the hardware, Xen calls the native PSCI system_reset method. On x86, Xen calls efi_reset_system on EFI systems, and has several fall backs if that doesn't work as expected (see xen/arch/x86/shutdown.c:machine_restart). But on a second look it doesn't look like that the capsule hypercalls are implemented correctly even on x86 (there is an "XXX fall through for now" comment in the code). I guess they are not available on Xen at all unfortunately.That is incredibly unfortunate. It effectively renders the firmware non-updateable when using Xen.Does that override PSCI?It does not, HYPERVISOR_sched_op(xen_restart,) is in addition to it. It ends up calling the same function within Xen as PSCI system_reset.I meant within Dom0. Presumably Dom0 calls HYPERVISOR_sched_op(xen_restart,), and doesn't ever call PSCI SYSTEM_RESET? In machine_restart we try efi_reboot first specifically to allow for capsule updates. Similarly drivers/firmware/efi/reboot.c registers efi_power_off late in order to override anything else, though that's best-effort at present.That's very interesting. I think that Xen on ARM should follow what Linux does and what Xen already does on x86 and try efi_reset_system first on efi systems.I would agree. Thanks, Mark. -- Shannon _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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