* [PATCH v2] x86/efi: Disable runtime services on kexec kernel if booted with efi=old_map
@ 2017-05-17 1:14 Sai Praneeth Prakhya
2017-05-17 1:57 ` Dave Young
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Sai Praneeth Prakhya @ 2017-05-17 1:14 UTC (permalink / raw)
To: linux-efi, linux-kernel
Cc: Sai Praneeth, Borislav Petkov, Ricardo Neri, Matt Fleming,
Ard Biesheuvel, Ravi Shankar, Lee Chun-Yi, Dave Young
From: Sai Praneeth <sai.praneeth.prakhya@intel.com>
Booting kexec kernel with "efi=old_map" in kernel command line hits
kernel panic as shown below.
[0.001000] BUG: unable to handle kernel paging request at ffff88007fe78070
[0.001000] IP: virt_efi_set_variable.part.7+0x63/0x1b0
[0.001000] PGD 7ea28067
[0.001000] PUD 7ea2b067
[0.001000] PMD 7ea2d067
[0.001000] PTE 0
[0.001000]
[0.001000] Oops: 0000 [#1] SMP
[0.001000] Modules linked in:
[0.001000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.11.0-rc2-yocto-standard+ #229
[0.001000] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015
[0.001000] task: ffffffff82022500 task.stack: ffffffff82000000
[0.001000] RIP: 0010:virt_efi_set_variable.part.7+0x63/0x1b0
[0.001000] RSP: 0000:ffffffff82003dc0 EFLAGS: 00010246
[0.001000] RAX: ffff88007fe78018 RBX: ffffffff82050300 RCX: 0000000000000007
[0.001000] RDX: ffffffff82003e50 RSI: ffffffff82050300 RDI: ffffffff82050300
[0.001000] RBP: ffffffff82003e08 R08: 0000000000000000 R09: 0000000000000000
[0.001000] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff82003e50
[0.001000] R13: 0000000000000007 R14: 0000000000000246 R15: 0000000000000000
[0.001000] FS: 0000000000000000(0000) GS:ffff88007fa00000(0000) knlGS:0000000000000000
[0.001000] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[0.001000] CR2: ffff88007fe78070 CR3: 000000007da1d000 CR4: 00000000000006b0
[0.001000] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[0.001000] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[0.001000] Call Trace:
[0.001000] virt_efi_set_variable+0x5d/0x70
[0.001000] efi_delete_dummy_variable+0x7a/0x80
[0.001000] efi_enter_virtual_mode+0x3f6/0x4a7
[0.001000] start_kernel+0x375/0x400
[0.001000] x86_64_start_reservations+0x2a/0x2c
[0.001000] x86_64_start_kernel+0x168/0x176
[0.001000] start_cpu+0x14/0x14
[0.001000] Code: 04 b0 84 ff 80 3d c5 56 b3 00 00 4c 8b 44 24 08 75
6b 9c 41 5e 48 8b 05 9c 78 99 00 4d 89 c1 48 89 de 4d 89 f8 44 89 e9 4c
89 e2 <48> 8b 40 58 48 8b 78 58 e8 b0 2d 88 ff 48 c7 c6 b6 1d f4 81 4c
[0.001000] RIP: virt_efi_set_variable.part.7+0x63/0x1b0 RSP: ffffffff82003dc0
[0.001000] CR2: ffff88007fe78070
[0.001000] ---[ end trace 0000000000000000 ]---
[0.001000] Kernel panic - not syncing: Attempted to kill the idle task!
[0.001000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task!
[efi=old_map was never intended to work with kexec. The problem with
using efi=old_map is that the virtual addresses are assigned from the
memory region used by other kernel mappings; vmalloc() space.
Potentially there could be collisions when booting kexec if something
else is mapped at the virtual address we allocated for runtime service
regions in the initial boot] - Matt Fleming
Since kexec was never intended to work with efi=old_map, disable
runtime services in kexec if booted with efi=old_map, so that we don't
panic.
Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Ricardo Neri <ricardo.neri@intel.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Cc: Lee Chun-Yi <jlee@suse.com>
Cc: Dave Young <dyoung@redhat.com>
Changes since v1:
Don't fix the panic, because this was never intended to work.
---
arch/x86/platform/efi/efi.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 87835c97611f..627b7b86f369 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -827,9 +827,11 @@ static void __init kexec_enter_virtual_mode(void)
/*
* We don't do virtual mode, since we don't do runtime services, on
- * non-native EFI
+ * non-native EFI. With efi=old_map, we don't do runtime services in
+ * kexec kernel because in the initial boot something else might
+ * have been mapped at these virtual addresses.
*/
- if (!efi_is_native()) {
+ if (!efi_is_native() || efi_enabled(EFI_OLD_MEMMAP)) {
efi_memmap_unmap();
clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
return;
--
2.1.4
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v2] x86/efi: Disable runtime services on kexec kernel if booted with efi=old_map
2017-05-17 1:14 [PATCH v2] x86/efi: Disable runtime services on kexec kernel if booted with efi=old_map Sai Praneeth Prakhya
@ 2017-05-17 1:57 ` Dave Young
2017-05-17 1:59 ` Sai Praneeth Prakhya
2017-05-17 7:29 ` joeyli
2017-05-25 11:58 ` Matt Fleming
2 siblings, 1 reply; 5+ messages in thread
From: Dave Young @ 2017-05-17 1:57 UTC (permalink / raw)
To: Sai Praneeth Prakhya
Cc: linux-efi, linux-kernel, Borislav Petkov, Ricardo Neri,
Matt Fleming, Ard Biesheuvel, Ravi Shankar, Lee Chun-Yi
Hi Sai,
On 05/16/17 at 06:14pm, Sai Praneeth Prakhya wrote:
> From: Sai Praneeth <sai.praneeth.prakhya@intel.com>
>
> Booting kexec kernel with "efi=old_map" in kernel command line hits
> kernel panic as shown below.
>
> [0.001000] BUG: unable to handle kernel paging request at ffff88007fe78070
> [0.001000] IP: virt_efi_set_variable.part.7+0x63/0x1b0
> [0.001000] PGD 7ea28067
> [0.001000] PUD 7ea2b067
> [0.001000] PMD 7ea2d067
> [0.001000] PTE 0
> [0.001000]
> [0.001000] Oops: 0000 [#1] SMP
> [0.001000] Modules linked in:
> [0.001000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.11.0-rc2-yocto-standard+ #229
> [0.001000] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015
> [0.001000] task: ffffffff82022500 task.stack: ffffffff82000000
> [0.001000] RIP: 0010:virt_efi_set_variable.part.7+0x63/0x1b0
> [0.001000] RSP: 0000:ffffffff82003dc0 EFLAGS: 00010246
> [0.001000] RAX: ffff88007fe78018 RBX: ffffffff82050300 RCX: 0000000000000007
> [0.001000] RDX: ffffffff82003e50 RSI: ffffffff82050300 RDI: ffffffff82050300
> [0.001000] RBP: ffffffff82003e08 R08: 0000000000000000 R09: 0000000000000000
> [0.001000] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff82003e50
> [0.001000] R13: 0000000000000007 R14: 0000000000000246 R15: 0000000000000000
> [0.001000] FS: 0000000000000000(0000) GS:ffff88007fa00000(0000) knlGS:0000000000000000
> [0.001000] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [0.001000] CR2: ffff88007fe78070 CR3: 000000007da1d000 CR4: 00000000000006b0
> [0.001000] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [0.001000] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [0.001000] Call Trace:
> [0.001000] virt_efi_set_variable+0x5d/0x70
> [0.001000] efi_delete_dummy_variable+0x7a/0x80
> [0.001000] efi_enter_virtual_mode+0x3f6/0x4a7
> [0.001000] start_kernel+0x375/0x400
> [0.001000] x86_64_start_reservations+0x2a/0x2c
> [0.001000] x86_64_start_kernel+0x168/0x176
> [0.001000] start_cpu+0x14/0x14
> [0.001000] Code: 04 b0 84 ff 80 3d c5 56 b3 00 00 4c 8b 44 24 08 75
> 6b 9c 41 5e 48 8b 05 9c 78 99 00 4d 89 c1 48 89 de 4d 89 f8 44 89 e9 4c
> 89 e2 <48> 8b 40 58 48 8b 78 58 e8 b0 2d 88 ff 48 c7 c6 b6 1d f4 81 4c
> [0.001000] RIP: virt_efi_set_variable.part.7+0x63/0x1b0 RSP: ffffffff82003dc0
> [0.001000] CR2: ffff88007fe78070
> [0.001000] ---[ end trace 0000000000000000 ]---
> [0.001000] Kernel panic - not syncing: Attempted to kill the idle task!
> [0.001000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task!
>
> [efi=old_map was never intended to work with kexec. The problem with
> using efi=old_map is that the virtual addresses are assigned from the
> memory region used by other kernel mappings; vmalloc() space.
> Potentially there could be collisions when booting kexec if something
> else is mapped at the virtual address we allocated for runtime service
> regions in the initial boot] - Matt Fleming
>
> Since kexec was never intended to work with efi=old_map, disable
> runtime services in kexec if booted with efi=old_map, so that we don't
> panic.
>
> Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: Ricardo Neri <ricardo.neri@intel.com>
> Cc: Matt Fleming <matt@codeblueprint.co.uk>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Ravi Shankar <ravi.v.shankar@intel.com>
> Cc: Lee Chun-Yi <jlee@suse.com>
> Cc: Dave Young <dyoung@redhat.com>
>
> Changes since v1:
> Don't fix the panic, because this was never intended to work.
> ---
> arch/x86/platform/efi/efi.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
> index 87835c97611f..627b7b86f369 100644
> --- a/arch/x86/platform/efi/efi.c
> +++ b/arch/x86/platform/efi/efi.c
> @@ -827,9 +827,11 @@ static void __init kexec_enter_virtual_mode(void)
>
> /*
> * We don't do virtual mode, since we don't do runtime services, on
> - * non-native EFI
> + * non-native EFI. With efi=old_map, we don't do runtime services in
> + * kexec kernel because in the initial boot something else might
> + * have been mapped at these virtual addresses.
> */
> - if (!efi_is_native()) {
> + if (!efi_is_native() || efi_enabled(EFI_OLD_MEMMAP)) {
> efi_memmap_unmap();
> clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
> return;
> --
> 2.1.4
>
Suppose it has passed the test on your hardware:
Acked-by: Dave Young <dyoung@redhat.com>
Thanks
Dave
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] x86/efi: Disable runtime services on kexec kernel if booted with efi=old_map
2017-05-17 1:57 ` Dave Young
@ 2017-05-17 1:59 ` Sai Praneeth Prakhya
0 siblings, 0 replies; 5+ messages in thread
From: Sai Praneeth Prakhya @ 2017-05-17 1:59 UTC (permalink / raw)
To: Dave Young
Cc: linux-efi, linux-kernel, Borislav Petkov, Ricardo Neri,
Matt Fleming, Ard Biesheuvel, Ravi Shankar, Lee Chun-Yi
On Wed, 2017-05-17 at 09:57 +0800, Dave Young wrote:
> Hi Sai,
> On 05/16/17 at 06:14pm, Sai Praneeth Prakhya wrote:
> > From: Sai Praneeth <sai.praneeth.prakhya@intel.com>
> >
> > Booting kexec kernel with "efi=old_map" in kernel command line hits
> > kernel panic as shown below.
> >
> > [0.001000] BUG: unable to handle kernel paging request at ffff88007fe78070
> > [0.001000] IP: virt_efi_set_variable.part.7+0x63/0x1b0
> > [0.001000] PGD 7ea28067
> > [0.001000] PUD 7ea2b067
> > [0.001000] PMD 7ea2d067
> > [0.001000] PTE 0
> > [0.001000]
> > [0.001000] Oops: 0000 [#1] SMP
> > [0.001000] Modules linked in:
> > [0.001000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.11.0-rc2-yocto-standard+ #229
> > [0.001000] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015
> > [0.001000] task: ffffffff82022500 task.stack: ffffffff82000000
> > [0.001000] RIP: 0010:virt_efi_set_variable.part.7+0x63/0x1b0
> > [0.001000] RSP: 0000:ffffffff82003dc0 EFLAGS: 00010246
> > [0.001000] RAX: ffff88007fe78018 RBX: ffffffff82050300 RCX: 0000000000000007
> > [0.001000] RDX: ffffffff82003e50 RSI: ffffffff82050300 RDI: ffffffff82050300
> > [0.001000] RBP: ffffffff82003e08 R08: 0000000000000000 R09: 0000000000000000
> > [0.001000] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff82003e50
> > [0.001000] R13: 0000000000000007 R14: 0000000000000246 R15: 0000000000000000
> > [0.001000] FS: 0000000000000000(0000) GS:ffff88007fa00000(0000) knlGS:0000000000000000
> > [0.001000] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > [0.001000] CR2: ffff88007fe78070 CR3: 000000007da1d000 CR4: 00000000000006b0
> > [0.001000] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > [0.001000] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> > [0.001000] Call Trace:
> > [0.001000] virt_efi_set_variable+0x5d/0x70
> > [0.001000] efi_delete_dummy_variable+0x7a/0x80
> > [0.001000] efi_enter_virtual_mode+0x3f6/0x4a7
> > [0.001000] start_kernel+0x375/0x400
> > [0.001000] x86_64_start_reservations+0x2a/0x2c
> > [0.001000] x86_64_start_kernel+0x168/0x176
> > [0.001000] start_cpu+0x14/0x14
> > [0.001000] Code: 04 b0 84 ff 80 3d c5 56 b3 00 00 4c 8b 44 24 08 75
> > 6b 9c 41 5e 48 8b 05 9c 78 99 00 4d 89 c1 48 89 de 4d 89 f8 44 89 e9 4c
> > 89 e2 <48> 8b 40 58 48 8b 78 58 e8 b0 2d 88 ff 48 c7 c6 b6 1d f4 81 4c
> > [0.001000] RIP: virt_efi_set_variable.part.7+0x63/0x1b0 RSP: ffffffff82003dc0
> > [0.001000] CR2: ffff88007fe78070
> > [0.001000] ---[ end trace 0000000000000000 ]---
> > [0.001000] Kernel panic - not syncing: Attempted to kill the idle task!
> > [0.001000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task!
> >
> > [efi=old_map was never intended to work with kexec. The problem with
> > using efi=old_map is that the virtual addresses are assigned from the
> > memory region used by other kernel mappings; vmalloc() space.
> > Potentially there could be collisions when booting kexec if something
> > else is mapped at the virtual address we allocated for runtime service
> > regions in the initial boot] - Matt Fleming
> >
> > Since kexec was never intended to work with efi=old_map, disable
> > runtime services in kexec if booted with efi=old_map, so that we don't
> > panic.
> >
> > Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
> > Cc: Borislav Petkov <bp@alien8.de>
> > Cc: Ricardo Neri <ricardo.neri@intel.com>
> > Cc: Matt Fleming <matt@codeblueprint.co.uk>
> > Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> > Cc: Ravi Shankar <ravi.v.shankar@intel.com>
> > Cc: Lee Chun-Yi <jlee@suse.com>
> > Cc: Dave Young <dyoung@redhat.com>
> >
> > Changes since v1:
> > Don't fix the panic, because this was never intended to work.
> > ---
> > arch/x86/platform/efi/efi.c | 6 ++++--
> > 1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
> > index 87835c97611f..627b7b86f369 100644
> > --- a/arch/x86/platform/efi/efi.c
> > +++ b/arch/x86/platform/efi/efi.c
> > @@ -827,9 +827,11 @@ static void __init kexec_enter_virtual_mode(void)
> >
> > /*
> > * We don't do virtual mode, since we don't do runtime services, on
> > - * non-native EFI
> > + * non-native EFI. With efi=old_map, we don't do runtime services in
> > + * kexec kernel because in the initial boot something else might
> > + * have been mapped at these virtual addresses.
> > */
> > - if (!efi_is_native()) {
> > + if (!efi_is_native() || efi_enabled(EFI_OLD_MEMMAP)) {
> > efi_memmap_unmap();
> > clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
> > return;
> > --
> > 2.1.4
> >
>
> Suppose it has passed the test on your hardware:
> Acked-by: Dave Young <dyoung@redhat.com>
>
Thanks Dave! Haha... yes.
I tested on qemu with OVMF
> Thanks
> Dave
Regards,
Sai
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] x86/efi: Disable runtime services on kexec kernel if booted with efi=old_map
2017-05-17 1:14 [PATCH v2] x86/efi: Disable runtime services on kexec kernel if booted with efi=old_map Sai Praneeth Prakhya
2017-05-17 1:57 ` Dave Young
@ 2017-05-17 7:29 ` joeyli
2017-05-25 11:58 ` Matt Fleming
2 siblings, 0 replies; 5+ messages in thread
From: joeyli @ 2017-05-17 7:29 UTC (permalink / raw)
To: Sai Praneeth Prakhya
Cc: linux-efi, linux-kernel, Borislav Petkov, Ricardo Neri,
Matt Fleming, Ard Biesheuvel, Ravi Shankar, Dave Young
On Tue, May 16, 2017 at 06:14:23PM -0700, Sai Praneeth Prakhya wrote:
> From: Sai Praneeth <sai.praneeth.prakhya@intel.com>
>
> Booting kexec kernel with "efi=old_map" in kernel command line hits
> kernel panic as shown below.
>
> [0.001000] BUG: unable to handle kernel paging request at ffff88007fe78070
> [0.001000] IP: virt_efi_set_variable.part.7+0x63/0x1b0
> [0.001000] PGD 7ea28067
> [0.001000] PUD 7ea2b067
> [0.001000] PMD 7ea2d067
> [0.001000] PTE 0
> [0.001000]
> [0.001000] Oops: 0000 [#1] SMP
> [0.001000] Modules linked in:
> [0.001000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.11.0-rc2-yocto-standard+ #229
> [0.001000] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015
> [0.001000] task: ffffffff82022500 task.stack: ffffffff82000000
> [0.001000] RIP: 0010:virt_efi_set_variable.part.7+0x63/0x1b0
> [0.001000] RSP: 0000:ffffffff82003dc0 EFLAGS: 00010246
> [0.001000] RAX: ffff88007fe78018 RBX: ffffffff82050300 RCX: 0000000000000007
> [0.001000] RDX: ffffffff82003e50 RSI: ffffffff82050300 RDI: ffffffff82050300
> [0.001000] RBP: ffffffff82003e08 R08: 0000000000000000 R09: 0000000000000000
> [0.001000] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff82003e50
> [0.001000] R13: 0000000000000007 R14: 0000000000000246 R15: 0000000000000000
> [0.001000] FS: 0000000000000000(0000) GS:ffff88007fa00000(0000) knlGS:0000000000000000
> [0.001000] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [0.001000] CR2: ffff88007fe78070 CR3: 000000007da1d000 CR4: 00000000000006b0
> [0.001000] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [0.001000] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [0.001000] Call Trace:
> [0.001000] virt_efi_set_variable+0x5d/0x70
> [0.001000] efi_delete_dummy_variable+0x7a/0x80
> [0.001000] efi_enter_virtual_mode+0x3f6/0x4a7
> [0.001000] start_kernel+0x375/0x400
> [0.001000] x86_64_start_reservations+0x2a/0x2c
> [0.001000] x86_64_start_kernel+0x168/0x176
> [0.001000] start_cpu+0x14/0x14
> [0.001000] Code: 04 b0 84 ff 80 3d c5 56 b3 00 00 4c 8b 44 24 08 75
> 6b 9c 41 5e 48 8b 05 9c 78 99 00 4d 89 c1 48 89 de 4d 89 f8 44 89 e9 4c
> 89 e2 <48> 8b 40 58 48 8b 78 58 e8 b0 2d 88 ff 48 c7 c6 b6 1d f4 81 4c
> [0.001000] RIP: virt_efi_set_variable.part.7+0x63/0x1b0 RSP: ffffffff82003dc0
> [0.001000] CR2: ffff88007fe78070
> [0.001000] ---[ end trace 0000000000000000 ]---
> [0.001000] Kernel panic - not syncing: Attempted to kill the idle task!
> [0.001000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task!
>
> [efi=old_map was never intended to work with kexec. The problem with
> using efi=old_map is that the virtual addresses are assigned from the
> memory region used by other kernel mappings; vmalloc() space.
> Potentially there could be collisions when booting kexec if something
> else is mapped at the virtual address we allocated for runtime service
> regions in the initial boot] - Matt Fleming
>
> Since kexec was never intended to work with efi=old_map, disable
> runtime services in kexec if booted with efi=old_map, so that we don't
> panic.
>
> Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: Ricardo Neri <ricardo.neri@intel.com>
> Cc: Matt Fleming <matt@codeblueprint.co.uk>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Ravi Shankar <ravi.v.shankar@intel.com>
> Cc: Lee Chun-Yi <jlee@suse.com>
> Cc: Dave Young <dyoung@redhat.com>
>
> Changes since v1:
> Don't fix the panic, because this was never intended to work.
I tested this patch on OVMF and Acer UEFI laptop. It works to me
for efi=old_map with crash kernel.
Tested-by: "Lee, Chun-Yi" <jlee@suse.com>
> ---
> arch/x86/platform/efi/efi.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
> index 87835c97611f..627b7b86f369 100644
> --- a/arch/x86/platform/efi/efi.c
> +++ b/arch/x86/platform/efi/efi.c
> @@ -827,9 +827,11 @@ static void __init kexec_enter_virtual_mode(void)
>
> /*
> * We don't do virtual mode, since we don't do runtime services, on
> - * non-native EFI
> + * non-native EFI. With efi=old_map, we don't do runtime services in
> + * kexec kernel because in the initial boot something else might
> + * have been mapped at these virtual addresses.
> */
> - if (!efi_is_native()) {
> + if (!efi_is_native() || efi_enabled(EFI_OLD_MEMMAP)) {
> efi_memmap_unmap();
> clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
> return;
> --
> 2.1.4
>
Thanks a lot!
Joey Lee
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] x86/efi: Disable runtime services on kexec kernel if booted with efi=old_map
2017-05-17 1:14 [PATCH v2] x86/efi: Disable runtime services on kexec kernel if booted with efi=old_map Sai Praneeth Prakhya
2017-05-17 1:57 ` Dave Young
2017-05-17 7:29 ` joeyli
@ 2017-05-25 11:58 ` Matt Fleming
2 siblings, 0 replies; 5+ messages in thread
From: Matt Fleming @ 2017-05-25 11:58 UTC (permalink / raw)
To: Sai Praneeth Prakhya
Cc: linux-efi, linux-kernel, Borislav Petkov, Ricardo Neri,
Ard Biesheuvel, Ravi Shankar, Lee Chun-Yi, Dave Young
On Tue, 16 May, at 06:14:23PM, Sai Praneeth Prakhya wrote:
> From: Sai Praneeth <sai.praneeth.prakhya@intel.com>
>
> Booting kexec kernel with "efi=old_map" in kernel command line hits
> kernel panic as shown below.
>
> [0.001000] BUG: unable to handle kernel paging request at ffff88007fe78070
> [0.001000] IP: virt_efi_set_variable.part.7+0x63/0x1b0
> [0.001000] PGD 7ea28067
> [0.001000] PUD 7ea2b067
> [0.001000] PMD 7ea2d067
> [0.001000] PTE 0
> [0.001000]
> [0.001000] Oops: 0000 [#1] SMP
> [0.001000] Modules linked in:
> [0.001000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.11.0-rc2-yocto-standard+ #229
> [0.001000] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015
> [0.001000] task: ffffffff82022500 task.stack: ffffffff82000000
> [0.001000] RIP: 0010:virt_efi_set_variable.part.7+0x63/0x1b0
> [0.001000] RSP: 0000:ffffffff82003dc0 EFLAGS: 00010246
> [0.001000] RAX: ffff88007fe78018 RBX: ffffffff82050300 RCX: 0000000000000007
> [0.001000] RDX: ffffffff82003e50 RSI: ffffffff82050300 RDI: ffffffff82050300
> [0.001000] RBP: ffffffff82003e08 R08: 0000000000000000 R09: 0000000000000000
> [0.001000] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff82003e50
> [0.001000] R13: 0000000000000007 R14: 0000000000000246 R15: 0000000000000000
> [0.001000] FS: 0000000000000000(0000) GS:ffff88007fa00000(0000) knlGS:0000000000000000
> [0.001000] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [0.001000] CR2: ffff88007fe78070 CR3: 000000007da1d000 CR4: 00000000000006b0
> [0.001000] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [0.001000] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [0.001000] Call Trace:
> [0.001000] virt_efi_set_variable+0x5d/0x70
> [0.001000] efi_delete_dummy_variable+0x7a/0x80
> [0.001000] efi_enter_virtual_mode+0x3f6/0x4a7
> [0.001000] start_kernel+0x375/0x400
> [0.001000] x86_64_start_reservations+0x2a/0x2c
> [0.001000] x86_64_start_kernel+0x168/0x176
> [0.001000] start_cpu+0x14/0x14
> [0.001000] Code: 04 b0 84 ff 80 3d c5 56 b3 00 00 4c 8b 44 24 08 75
> 6b 9c 41 5e 48 8b 05 9c 78 99 00 4d 89 c1 48 89 de 4d 89 f8 44 89 e9 4c
> 89 e2 <48> 8b 40 58 48 8b 78 58 e8 b0 2d 88 ff 48 c7 c6 b6 1d f4 81 4c
> [0.001000] RIP: virt_efi_set_variable.part.7+0x63/0x1b0 RSP: ffffffff82003dc0
> [0.001000] CR2: ffff88007fe78070
> [0.001000] ---[ end trace 0000000000000000 ]---
> [0.001000] Kernel panic - not syncing: Attempted to kill the idle task!
> [0.001000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task!
>
> [efi=old_map was never intended to work with kexec. The problem with
> using efi=old_map is that the virtual addresses are assigned from the
> memory region used by other kernel mappings; vmalloc() space.
> Potentially there could be collisions when booting kexec if something
> else is mapped at the virtual address we allocated for runtime service
> regions in the initial boot] - Matt Fleming
>
> Since kexec was never intended to work with efi=old_map, disable
> runtime services in kexec if booted with efi=old_map, so that we don't
> panic.
>
> Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: Ricardo Neri <ricardo.neri@intel.com>
> Cc: Matt Fleming <matt@codeblueprint.co.uk>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Ravi Shankar <ravi.v.shankar@intel.com>
> Cc: Lee Chun-Yi <jlee@suse.com>
> Cc: Dave Young <dyoung@redhat.com>
>
> Changes since v1:
> Don't fix the panic, because this was never intended to work.
> ---
> arch/x86/platform/efi/efi.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
Thanks Sai, applied to the urgent branch.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2017-05-25 11:58 UTC | newest]
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2017-05-17 1:14 [PATCH v2] x86/efi: Disable runtime services on kexec kernel if booted with efi=old_map Sai Praneeth Prakhya
2017-05-17 1:57 ` Dave Young
2017-05-17 1:59 ` Sai Praneeth Prakhya
2017-05-17 7:29 ` joeyli
2017-05-25 11:58 ` Matt Fleming
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