Re: [PATCH 02/20] KVM: selftests: Bump the minimum GPA for page tables to 0x200000

[Claudio Imbrenda]

On Fri, 28 Aug 2026 11:07:34 -0700
Sean Christopherson <seanjc@xxxxxxxxxx> wrote:

> On Fri, Aug 28, 2026, Claudio Imbrenda wrote:
> > On Wed, 26 Aug 2026 16:04:53 -0700
> > Sean Christopherson <seanjc@xxxxxxxxxx> wrote:
> >   
> > > Bump selftests completely arbitrary minimum GPA for page tables from
> > > 0x180000 to 0x200000 (LoongArch's minimum), so that LoongArch can use
> > > vm_alloc_page_table() instead of open coding a rough equivalent.
> > > 
> > > Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> > > ---
> > >  tools/testing/selftests/kvm/include/kvm_util.h | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
> > > index 5a7a455b5387..70906a0d1003 100644
> > > --- a/tools/testing/selftests/kvm/include/kvm_util.h
> > > +++ b/tools/testing/selftests/kvm/include/kvm_util.h
> > > @@ -175,7 +175,7 @@ static inline struct userspace_mem_region *vm_get_mem_region(struct kvm_vm *vm,
> > >  
> > >  /* Minimum allocated guest virtual and physical addresses */
> > >  #define KVM_UTIL_MIN_VADDR		0x2000
> > > -#define KVM_GUEST_PAGE_TABLE_MIN_PADDR	0x180000
> > > +#define KVM_GUEST_PAGE_TABLE_MIN_PADDR	0x200000
> > >  
> > >  #define DEFAULT_GUEST_STACK_VADDR_MIN	0xab6000
> > >  #define DEFAULT_STACK_PGS		5  
> > 
> > this breaks s390/cmma_test
> > 
> > I tried a quick fix, but nope... I will need to actually invest some
> > time (i.e. next week) to understand why the quick fix is not enough,
> > and come up with a proper fix
> > 
> > the good news is: it seems like cmma_test is the only test that is
> > negatively affected by this series.  
> 
> Is it this change specifically that's problematic?  Because if so, you can probably

yesn't

wihtout this patch everything works for s390, but my quick fix should
have worked...

so I still need to debug why things don't work the way I expect, but at
least now my bug chase is independent from this series :)

> just do nothing, because Sashiko (argh, just remembered that Sashiko doesn't Cc
> everyone) pointed out that this will likely break some arm64 tests as well[*].
> 
> The LoongArch folks confirmed that using KVM_GUEST_PAGE_TABLE_MIN_PADDR as-is
> should be a-ok, so my plan is to drop this patch and instead have LoongArch use
> KVM_GUEST_PAGE_TABLE_MIN_PADDR.  I.e. make LoongArch match everyone else, instead
> of making everyone else match LoongArch.
> 
> [*] https://lore.kernel.org/all/20260826232224.782021F000E9@xxxxxxxxxxxxxxx
> 

if you respin without this patch I'll Ack