[v3,0/2] Optionally call EFI SetVirtualAddressMap()

Message

Marek Marczykowski-Górecki Oct. 12, 2019, 10:11 p.m. UTC

Workaround buggy UEFI accessing boot services memory after ExitBootServices().
Patches discussed here:
https://lists.xenproject.org/archives/html/xen-devel/2019-08/msg00701.html

In addition to the tests below, I've tested kexec on xen.efi with this option
enabled and it (still) works.

Test results on few laptops:

Thinkpad x230, firmware version 2.77:
 - without the patch: crashes on RS call (mapbs helps)
 - with patch: works
 - same with xen.efi and MB2

Librem 14 v1, firmware version (AMI) ARUD026 (06/18/2015):
 - without the patch: works
 - with the patch: works
 - same with xen.efi and MB2

Dell Latitude E6420, firmware version A21:
 this machine requires efi=attr=uc workaround
 - without the patch: dom0 hangs before sending any message to the console (even with earlyprintk=xen etc)
 - with the patch: crashes before dom0 prints anything: mm.c:896:d0v0 non-privileged attempt to map MMIO space 2c2c2c2c2c
 - same with xen.efi and MB2

Thinkpad W540:
 - without the patch: crashes on RS call (only efi=no-rs helps)
 - with patch: works
 - tested only with MB2

Thinkpad X1 Carbon gen5, firmware version 1.22 (2017-07-04):
 - without the patch: works
 - with patch: works
 - tested only xen.efi

Thinkpad P52, firmware version 1.25 (2018-04-15):
 - without the patch (MB2): hangs on RS call (mapbs helps)
 - without the patch (xen.efi): works(?!)
 - with the patch: works
 - tested with xen.efi and MB2

Changes in v2:
 - fix boot with xen.efi (efi_memmap at this point still needs to be accessed
   via physical address). TBH, I don't understand why previous version worked
   with MB2 - is directmap mapped at this point?

Cc: Juergen Gross <[e-mail]>
Cc: Andrew Cooper <[e-mail]>
Cc: George Dunlap <[e-mail]>
Cc: Ian Jackson <[e-mail]>
Cc: Jan Beulich <[e-mail]>
Cc: Julien Grall <[e-mail]>
Cc: Konrad Rzeszutek Wilk <[e-mail]>
Cc: Stefano Stabellini <[e-mail]>
Cc: Tim Deegan <[e-mail]>
Cc: Wei Liu <[e-mail]>
Cc: Jason Andryuk <[e-mail]>

Marek Marczykowski-Górecki (2):
  efi: remove old SetVirtualAddressMap() arrangement
  xen/efi: optionally call SetVirtualAddressMap()

 xen/common/Kconfig    | 13 ++++++++++++-
 xen/common/efi/boot.c | 48 +++++++++++++++++++++++---------------------
 2 files changed, 39 insertions(+), 22 deletions(-)

base-commit: 7a4e6711114905b3cbbe48e81c3222361a7f3579

Comments

Jason Andryuk Oct. 15, 2019, 12:25 p.m. UTC | #1

On Sat, Oct 12, 2019 at 6:11 PM Marek Marczykowski-Górecki
<[e-mail]> wrote:
>
> Workaround buggy UEFI accessing boot services memory after ExitBootServices().
> Patches discussed here:
> https://lists.xenproject.org/archives/html/xen-devel/2019-08/msg00701.html
>
> In addition to the tests below, I've tested kexec on xen.efi with this option
> enabled and it (still) works.
>
> Test results on few laptops:
>
> Thinkpad x230, firmware version 2.77:
>  - without the patch: crashes on RS call (mapbs helps)
>  - with patch: works
>  - same with xen.efi and MB2
>
> Librem 14 v1, firmware version (AMI) ARUD026 (06/18/2015):
>  - without the patch: works
>  - with the patch: works
>  - same with xen.efi and MB2
>
> Dell Latitude E6420, firmware version A21:
>  this machine requires efi=attr=uc workaround
>  - without the patch: dom0 hangs before sending any message to the console (even with earlyprintk=xen etc)
>  - with the patch: crashes before dom0 prints anything: mm.c:896:d0v0 non-privileged attempt to map MMIO space 2c2c2c2c2c
>  - same with xen.efi and MB2
>
> Thinkpad W540:
>  - without the patch: crashes on RS call (only efi=no-rs helps)
>  - with patch: works
>  - tested only with MB2
>
> Thinkpad X1 Carbon gen5, firmware version 1.22 (2017-07-04):
>  - without the patch: works
>  - with patch: works
>  - tested only xen.efi
>
> Thinkpad P52, firmware version 1.25 (2018-04-15):
>  - without the patch (MB2): hangs on RS call (mapbs helps)
>  - without the patch (xen.efi): works(?!)
>  - with the patch: works
>  - tested with xen.efi and MB2
>
> Changes in v2:
>  - fix boot with xen.efi (efi_memmap at this point still needs to be accessed
>    via physical address). TBH, I don't understand why previous version worked
>    with MB2 - is directmap mapped at this point?

v1 failed to boot for me.

For v3:
Dell Latitude 5580, firmware 1.16.0
 - without the patch: works
 - with patch: works
 - tested only xen.efi

Tested-by: Jason Andryuk <[e-mail]>