linux-kernel - Re: [PATCH -v2] EFI: Runtime services virtual mapping

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Message-ID: <20130923054540.GB7007@dhcp-16-126.nay.redhat.com>
Date:	Mon, 23 Sep 2013 13:45:41 +0800
From:	Dave Young <dyoung@...hat.com>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	Borislav Petkov <bp@...en8.de>, X86 ML <x86@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Borislav Petkov <bp@...e.de>,
	Matt Fleming <matt@...sole-pimps.org>,
	Matthew Garrett <mjg59@...f.ucam.org>,
	James Bottomley <James.Bottomley@...senPartnership.com>,
	Vivek Goyal <vgoyal@...hat.com>, linux-efi@...r.kernel.org
Subject: Re: [PATCH -v2] EFI: Runtime services virtual mapping

On 09/22/13 at 08:27am, H. Peter Anvin wrote:
> The address that faults is interesting in that it is indeed just below -4G.  The question at hand is probably what information you are using to build the EFI mappings in the secondary kernel and what could make it not match the primary.
> 
> Assuming it isn't as simple as the mappings never get built at all.

At least the efi_info is same between two kernels.
Will print some debug info to see if I can find something.

> 
> 
> Borislav Petkov <bp@...en8.de> wrote:
> >On Sun, Sep 22, 2013 at 08:35:15PM +0800, Dave Young wrote:
> >> I tested your new patch, it works both with efi stub and grub boot in
> >> 1st kernel.
> >
> >Good, thanks!
> >
> >> But it paniced in kexec boot with my kexec related patcheset, the
> >patchset
> >
> >That's the second kernel, right?
> >
> >> contains 3 patch:
> >> 1. introduce cmdline kexecboot=<0|1|2>; 1 == kexec, 2 == kdump
> >> 2. export physical addr fw_vendor, runtime, tables to
> >/sys/firmware/efi/systab
> >> 3. if kexecboot != 0, use fw_vendor, runtime, tables from bootparams;
> >Also do not
> >>    call SetVirtualAddressMao in case kexecboot.
> >> 
> >> The panic happens at the last line of efi_init:
> >>         /* clean DUMMY object */
> >>         efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
> >>                          EFI_VARIABLE_NON_VOLATILE |
> >>                          EFI_VARIABLE_BOOTSERVICE_ACCESS |
> >>                          EFI_VARIABLE_RUNTIME_ACCESS,
> >>                          0, NULL);
> >> 
> >> Below is the dmesg:
> >> [    0.003359] pid_max: default: 32768 minimum: 301
> >> [    0.004792] BUG: unable to handle kernel paging request at
> >fffffffefde97e70
> >> [    0.006666] IP: [<ffffffff8103a1db>]
> >virt_efi_set_variable+0x40/0x54
> >> [    0.006666] PGD 36981067 PUD 35828063 PMD 0
> >
> >Here it is - fffffffefde97e70 is not mapped in the pagetable, PMD is 0.
> >
> >Ok, can you upload your patches somewhere and tell me exactly how to
> >reproduce this so that I can take a look too?
> >
> >Thanks.
> 
> -- 
> Sent from my mobile phone.  Please pardon brevity and lack of formatting.
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