[Qemu-devel] [Bug 1838277] Re: qemu-system-aarch64: regression: TCG sometimes using wrong values for VBAR_EL2 despite it being correctly reported to GDB

[Elouan Appéré]

ie. there's x20 being wrongly used in start.s in some places, meaning #8
can be discarded, but this does not explain the vbar_el2 bug (the repro
steps for which are above).

qemu *did* correctly jump to 0x60001200 (synchronous exception from same
EL with vbar_el2=0x60001000) in version 2.11, but not anymore.

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1838277

Title:
  qemu-system-aarch64: regression: TCG sometimes using wrong values for
  VBAR_EL2 despite it being correctly reported to GDB

Status in QEMU:
  New

Bug description:
  Affects 3.1.0 (latest stable release) and latest commit
  (893dc8300c80e3dc32f31e968cf7aa0904da50c3) but did *not* affect 2.11
  (qemu from bionic ubuntu LTS).

  With the following code and shell commands:

  test.s:

  .text
  mov x0, #0x60000000
  msr vbar_el2, x0
  dsb sy
  isb sy

  $ aarch64-none-elf-as test.s -o test.o
  $ aarch64-none-elf-objcopy -S -O binary test.o test.bin
  $ qemu-system-aarch64 -nographic -machine virt,virtualization=on -cpu 
cortex-a57 -kernel test.bin -s -S

  vbar_el2 is still 0 after the code, instead of being the expected
  0x60000000. (see screenshot).

  This regression doesn't seem to happen for vbar_el1 &
  virtualization=off.

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1838277/+subscriptions