| Message ID | 20231123003513.24292-3-ankita@nvidia.com |
|---|---|
| State | New |
| Headers | show |
| Series | mm: Implement ECC handling for pfn with no struct page | expand |
On Thu, Nov 23, 2023, ankita@nvidia.com wrote: > From: Ankit Agrawal <ankita@nvidia.com> > > The fixup_user_fault() currently does not expect a VM_FAULT_HWPOISON > and hence does not check for it while calling vm_fault_to_errno(). Since > we now have a new code path which can trigger such case, change > fixup_user_fault to look for VM_FAULT_HWPOISON. > > Also make hva_to_pfn_remapped check for -EHWPOISON and communicate the > poison fault up to the user_mem_abort(). I would much prefer the KVM change be split out to its own patch, I see no reason why it needs to be bundled with the fixup_user_fault() change. KVM will set pfn to KVM_PFN_ERR_FAULT before and after the fixup_user_fault() change. > Signed-off-by: Ankit Agrawal <ankita@nvidia.com> > --- > mm/gup.c | 2 +- > virt/kvm/kvm_main.c | 6 ++++++ > 2 files changed, 7 insertions(+), 1 deletion(-) > > diff --git a/mm/gup.c b/mm/gup.c > index 231711efa390..b78af20a0f52 100644 > --- a/mm/gup.c > +++ b/mm/gup.c > @@ -1414,7 +1414,7 @@ int fixup_user_fault(struct mm_struct *mm, > } > > if (ret & VM_FAULT_ERROR) { > - int err = vm_fault_to_errno(ret, 0); > + int err = vm_fault_to_errno(ret, FOLL_HWPOISON); > > if (err) > return err; > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 486800a7024b..2ff067f21a7c 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -2731,6 +2731,12 @@ kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool interruptible, > r = hva_to_pfn_remapped(vma, addr, write_fault, writable, &pfn); > if (r == -EAGAIN) > goto retry; > + > + if (r == -EHWPOISON) { > + pfn = KVM_PFN_ERR_HWPOISON; > + goto exit; > + } > + > if (r < 0) > pfn = KVM_PFN_ERR_FAULT; I vote for if (r == -EHWPOISON) pfn = KVM_PFN_ERR_HWPOISON; else if (r < 0) pfn = KVM_PFN_ERR_FAULT; or even opportunstically fix the < 0 weirdness: if (r == -EHWPOISON) pfn = KVM_PFN_ERR_HWPOISON; else if (r) pfn = KVM_PFN_ERR_FAULT; It's rather confusing to see a goto in one error path but an effective fallthrough in a different error path, i.e. gives the impression that KVM_PFN_ERR_HWPOISON has some special behavior that doesn't apply to KVM_PFN_ERR_FAULT.
diff --git a/mm/gup.c b/mm/gup.c index 231711efa390..b78af20a0f52 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1414,7 +1414,7 @@ int fixup_user_fault(struct mm_struct *mm, } if (ret & VM_FAULT_ERROR) { - int err = vm_fault_to_errno(ret, 0); + int err = vm_fault_to_errno(ret, FOLL_HWPOISON); if (err) return err; diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 486800a7024b..2ff067f21a7c 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2731,6 +2731,12 @@ kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool interruptible, r = hva_to_pfn_remapped(vma, addr, write_fault, writable, &pfn); if (r == -EAGAIN) goto retry; + + if (r == -EHWPOISON) { + pfn = KVM_PFN_ERR_HWPOISON; + goto exit; + } + if (r < 0) pfn = KVM_PFN_ERR_FAULT; } else {