linux-kernel - Re: [PATCH] RISC-V: KVM: Remove automatic I/O mapping for VM

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20251021153125.GA699957@nvidia.com>
Date: Tue, 21 Oct 2025 12:31:25 -0300
From: Jason Gunthorpe <jgg@...dia.com>
To: Guo Ren <guoren@...nel.org>
Cc: fangyu.yu@...ux.alibaba.com, anup@...infault.org, atish.patra@...ux.dev,
	pjw@...nel.org, palmer@...belt.com, aou@...s.berkeley.edu,
	alex@...ti.fr, pbonzini@...hat.com, jiangyifei@...wei.com,
	kvm@...r.kernel.org, kvm-riscv@...ts.infradead.org,
	linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
	alex.williamson@...hat.com
Subject: Re: [PATCH] RISC-V: KVM: Remove automatic I/O mapping for VM_PFNMAP

On Tue, Oct 21, 2025 at 08:27:50AM -0700, Guo Ren wrote:
> On Mon, Oct 20, 2025 at 6:08 AM <fangyu.yu@...ux.alibaba.com> wrote:
> >
> > From: Fangyu Yu <fangyu.yu@...ux.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.

Assuming things about vm_pgoff is certainly incorrect. Handling it
during a normal fault by looking up the actual PTE seems OK to me too.

Jason