[PATCH] RISC-V: KVM: Remove automatic I/O mapping for VM_PFNMAP
Anup Patel
anup at brainfault.org
Fri Oct 24 08:57:06 PDT 2025
On Fri, Oct 24, 2025 at 8:55 PM Anup Patel <anup at brainfault.org> wrote:
>
> On Fri, Oct 24, 2025 at 7:01 PM <fangyu.yu at linux.alibaba.com> wrote:
> >
> > >> From: Fangyu Yu <fangyu.yu at linux.alibaba.com>
> > >>
> > >> As of commit aac6db75a9fc ("vfio/pci: Use unmap_mapping_range()"),
> > >> vm_pgoff may no longer guaranteed to hold the PFN for VM_PFNMAP
> > >> regions. Using vma->vm_pgoff to derive the HPA here may therefore
> > >> produce incorrect mappings.
> > >>
> > >> Instead, I/O mappings for such regions can be established on-demand
> > >> during g-stage page faults, making the upfront ioremap in this path
> > >> is unnecessary.
> > >>
> > >> Fixes: 9d05c1fee837 ("RISC-V: KVM: Implement stage2 page table programming")
> > >> Signed-off-by: Fangyu Yu <fangyu.yu at linux.alibaba.com>
> > >
> > >LGTM.
> > >
> > >Queued it as fix for Linux-6.18
> > >
> > >Reviewed-by: Anup Patel <anup at brainfault.org>
> > >
> > >Thanks,
> > >Anup
> > >
> >
> > Hi Anup:
> >
> > Thanks for the review.
> >
> > Please note that this patch has two build warnings, and I have fixed
> > on patch V2:
> > https://lore.kernel.org/linux-riscv/20251021142131.78796-1-fangyu.yu@linux.alibaba.com/
> >
>
> Can you send a separate patch with Fixes tag to this patch?
>
> You can base the patch on riscv_kvm_next branch at:
> https://github.com/kvm-riscv/linux.git
>
For some reason, your v2 patch never showed up in my inbox :(
No need for a separate patch. I have picked your v2.
Regards,
Anup
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