[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] arm64: xen: Implement EFI reset_system callback
Hi, On 18/04/17 19:51, Juergen Gross wrote: On 18/04/17 20:46, Stefano Stabellini wrote:On Tue, 18 Apr 2017, Juergen Gross wrote:On 18/04/17 20:37, Stefano Stabellini wrote:On Thu, 6 Apr 2017, Juergen Gross wrote:On 06/04/17 18:43, Daniel Kiper wrote:On Thu, Apr 06, 2017 at 06:22:44PM +0200, Juergen Gross wrote:On 06/04/17 18:06, Daniel Kiper wrote:Hi Julien, On Thu, Apr 06, 2017 at 04:39:13PM +0100, Julien Grall wrote:Hi Daniel, On 06/04/17 16:20, Daniel Kiper wrote:On Thu, Apr 06, 2017 at 04:38:24PM +0200, Juergen Gross wrote:On 06/04/17 16:27, Daniel Kiper wrote:On Thu, Apr 06, 2017 at 09:32:32AM +0100, Julien Grall wrote:Hi Juergen, On 06/04/17 07:23, Juergen Gross wrote:On 05/04/17 21:49, Boris Ostrovsky wrote:On 04/05/2017 02:14 PM, Julien Grall wrote:The x86 code has theoritically a similar issue, altought EFI does not seem to be the preferred method. I have left it unimplemented on x86 and CCed Linux Xen x86 maintainers to know their view here.(+Daniel) This could be a problem for x86 as well, at least theoretically. xen_machine_power_off() may call pm_power_off(), which is efi.reset_system. So I think we should have a similar routine there.+1 I don't see any problem with such a routine added, in contrast to potential "reboots" instead of power off without it. So I think this dummy xen_efi_reset_system() should be added to drivers/xen/efi.c instead.I will resend the patch during day with xen_efi_reset_system moved to common code and implement the x86 counterpart (thought, I will not be able to test it).I think that this is ARM specific issue. On x86 machine_restart() calls xen_restart(). Hence, everything works. So, I think that it should be fixed only for ARM. Anyway, please CC me when you send a patch.What about xen_machine_power_off() (as stated in Boris' mail)?Guys what do you think about that: --- a/drivers/firmware/efi/reboot.c +++ b/drivers/firmware/efi/reboot.c @@ -55,7 +55,7 @@ static void efi_power_off(void) static int __init efi_shutdown_init(void) { - if (!efi_enabled(EFI_RUNTIME_SERVICES)) + if (!efi_enabled(EFI_RUNTIME_SERVICES) || efi_enabled(EFI_PARAVIRT)) return -ENODEV; if (efi_poweroff_required()) Julien, for ARM64 please take a look at arch/arm64/kernel/efi.c:efi_poweroff_required(void). I hope that tweaks for both files should solve our problem.This sounds good for power off (I haven't tried to power off DOM0 yet). But this will not solve the restart problem (see machine_restart in arch/arm64/kernel/process.c) which call directly efi_reboot.Hmmm... It seems to me that efi.reset_system override with empty function in arch/arm/xen/efi.c is the best solution. So, I see three patches here. One for drivers/firmware/efi/reboot.c, one for arch/arm/xen/efi.c and one for arch/arm64/kernel/efi.c. Does it make sense?I still think the empty function should be in drivers/xen/efi.c and we should use it in arch/x86/xen/efi.c, too.If you wish we can go that way too. Though I thing that we should fix drivers/firmware/efi/reboot.c:efi_shutdown_init() too. Just in case.Sure, go ahead. I won't object.For the Xen on ARM side, the original patch that started this thread (20170405181417.15985-1-julien.grall@xxxxxxx) is good to go, right?As I said: the dummy xen_efi_reset_system() should be in drivers/xen/efi.cOK. Who is working on it?Didn't Julien say he would do it? Yes. I looked at bit closer to the problem mention with power off. xen_efi_reset_system cannot be a NOP because there may not be fallback alternatives (see machine_power_off in arch/arm64/kernel/process.c) So I think we would have to translate EFI_RESET* to Xen SHUTDOWN_* and then call HYPERVISOR_sched_op directly. I will send a new version soon. Cheers, -- Julien Grall _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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