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

[Dave Young]

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.

Here is my debug output, diff efi-mapping-1st-kernel efi-mapping-2nd-kernel:
Obviously, the high address mapping is not same:

--- efi-mapping-1.txt	2013-09-24 10:46:09.977746047 +0800
+++ efi-mapping-2.txt	2013-09-24 10:46:33.871421806 +0800
@@ -1,30 +1,30 @@
 efi mapping PA 0x800000 -> VA 0x800000
 efi mapping PA 0x800000 -> VA 0xffffffff00000000
 efi mapping PA 0x7c000000 -> VA 0x7c000000
-efi mapping PA 0x7c000000 -> VA 0xfffffffefffe0000
+efi mapping PA 0x7c000000 -> VA 0xffffffff00000000
 efi mapping PA 0x7d5e2000 -> VA 0x7d5e2000
-efi mapping PA 0x7d5e2000 -> VA 0xfffffffefffdf000
+efi mapping PA 0x7d5e2000 -> VA 0xfffffffefffff000
 efi mapping PA 0x7d77d000 -> VA 0x7d77d000
-efi mapping PA 0x7d77d000 -> VA 0xfffffffefffde000
+efi mapping PA 0x7d77d000 -> VA 0xfffffffeffffe000
 efi mapping PA 0x7d864000 -> VA 0x7d864000
-efi mapping PA 0x7d864000 -> VA 0xfffffffeff8d4000
+efi mapping PA 0x7d864000 -> VA 0xfffffffeff8f4000
 efi mapping PA 0x7df6e000 -> VA 0x7df6e000
-efi mapping PA 0x7df6e000 -> VA 0xfffffffeff6ae000
+efi mapping PA 0x7df6e000 -> VA 0xfffffffeff6ce000
 efi mapping PA 0x7e194000 -> VA 0x7e194000
-efi mapping PA 0x7e194000 -> VA 0xfffffffeff6ac000
+efi mapping PA 0x7e194000 -> VA 0xfffffffeff6cc000
 efi mapping PA 0x7e196000 -> VA 0x7e196000
-efi mapping PA 0x7e196000 -> VA 0xfffffffeff696000
+efi mapping PA 0x7e196000 -> VA 0xfffffffeff6b6000
 efi mapping PA 0x7e1ac000 -> VA 0x7e1ac000
-efi mapping PA 0x7e1ac000 -> VA 0xfffffffeff681000
+efi mapping PA 0x7e1ac000 -> VA 0xfffffffeff6a1000
 efi mapping PA 0x7e1c1000 -> VA 0x7e1c1000
-efi mapping PA 0x7e1c1000 -> VA 0xfffffffefe041000
+efi mapping PA 0x7e1c1000 -> VA 0xfffffffefe061000
 efi mapping PA 0x7f802000 -> VA 0x7f802000
-efi mapping PA 0x7f802000 -> VA 0xfffffffefdec2000
+efi mapping PA 0x7f802000 -> VA 0xfffffffefdee2000
 efi mapping PA 0x7f981000 -> VA 0x7f981000
-efi mapping PA 0x7f981000 -> VA 0xfffffffefde92000
+efi mapping PA 0x7f981000 -> VA 0xfffffffefdeb2000
 efi mapping PA 0x7f9b1000 -> VA 0x7f9b1000
-efi mapping PA 0x7f9b1000 -> VA 0xfffffffefde6e000
+efi mapping PA 0x7f9b1000 -> VA 0xfffffffefde8e000
 efi mapping PA 0x7f9e5000 -> VA 0x7f9e5000
-efi mapping PA 0x7f9e5000 -> VA 0xfffffffefd873000
+efi mapping PA 0x7f9e5000 -> VA 0xfffffffefd893000
 efi mapping PA 0x7ffe0000 -> VA 0x7ffe0000
-efi mapping PA 0x7ffe0000 -> VA 0xfffffffefd853000
+efi mapping PA 0x7ffe0000 -> VA 0xfffffffefd873000

> 
> 
> Borislav Petkov <bp@xxxxxxxxx> 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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