[Xen-devel] [PATCH v2 0/2] Optionally call EFI SetVirtualAddressMap()

[Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>]

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

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 <jgross@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Julien Grall <julien.grall@xxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Tim Deegan <tim@xxxxxxx>
Cc: Wei Liu <wl@xxxxxxx>
Cc: Jason Andryuk <jandryuk@xxxxxxxxx>

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
-- 
git-series 0.9.1

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