On Thu, Jun 9, 2022 at 3:01 AM Bertrand Marquis
<[email protected]> wrote:
>
> Hi Michal,
>
> > On 9 Jun 2022, at 10:57, Michal Orzel via lists.yoctoproject.org 
> > <[email protected]> wrote:
> >
> > By default, highmem option is enabled for machine types later than
> > virt-2.12. This allows qemu to place devices and RAM in physical
> > address space above 32-bits. This can cause issues as according to the
> > documentation Xen supports up to 12GiB of physical address space.
> > Recently the issue was observed using runqemu, that was causing Linux
> > running on top of Xen to stall when trying to access ECAM space placed
> > by qemu at 256GiB mark. Even though this issue is most probably related
> > to QEMU and not Xen (the investigation showed that it can map ECAM
> > space correctly), it is best to avoid such issues by disabling highmem
> > on qemuarm.
> >
> > Signed-off-by: Michal Orzel <[email protected]>
> Reviewed-by: Bertrand Marquis <[email protected]>

Reviewed-by: Christopher Clark <[email protected]>

>
> Also tested on kirkstone and dom0 boots fine and pci is working.

Thanks,

Christopher

>
> Thanks a lot
> Cheers
> Bertrand
>
> > ---
> > classes/qemuboot-xen-defaults.bbclass | 6 ++++--
> > 1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/classes/qemuboot-xen-defaults.bbclass 
> > b/classes/qemuboot-xen-defaults.bbclass
> > index f1550cc..460cbe6 100644
> > --- a/classes/qemuboot-xen-defaults.bbclass
> > +++ b/classes/qemuboot-xen-defaults.bbclass
> > @@ -23,8 +23,10 @@ QB_DEFAULT_KERNEL:qemuarm = "xen-${MACHINE}"
> >
> > # 64-bit Arm: gic version 3
> > QB_MACHINE:qemuarm64 = "-machine virt,gic-version=3 -machine 
> > virtualization=true"
> > -# 32-bit Arm
> > -QB_MACHINE:qemuarm = "-machine virt -machine virtualization=true"
> > +# 32-bit Arm: highmem=off
> > +# Disable highmem so that qemu does not use highmem IO regions that end up
> > +# being placed at the 256GiB mark (e.g. ECAM space) and can cause issues 
> > in Xen.
> > +QB_MACHINE:qemuarm = "-machine virt,highmem=off -machine 
> > virtualization=true"
> >
> > # Increase the default qemu memory allocation to allow for the hypervisor.
> > # Use a weak assignment to allow for change of default and override 
> > elsewhere.
> > --
> > 2.25.1
> >
> >
> > 
> >
>
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