| Message ID | 20230220183847.59159-19-michael.roth@amd.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support | expand |
On Mon, 20 Feb 2023, Michael Roth wrote: > From: Hugh Dickins <hughd@google.com> No. > > When the address is backed by a memfd, the code to split the page does > nothing more than remove the PMD from the page tables. So immediately > install a PTE to ensure that any other pages in that 2MB region are > brought back as in 4K pages. > > Signed-off-by: Hugh Dickins <hughd@google.com> No. Suggested-by would be okay. > Cc: Hugh Dickins <hughd@google.com> Thanks. I'm really sorry to be such a jobsworth, and have nothing more constructive to say than I did before in https://lore.kernel.org/linux-mm/7f2228c4-1586-2934-7b92-1a9d23b6046@google.com/ (please re-read), but adding a Signed-off-by where none was given is wrong; and I'm not ever going to comprehend enough of the context to give it. Best of luck for the series, Hugh > Signed-off-by: Ashish Kalra <ashish.kalra@amd.com> > Signed-off-by: Michael Roth <michael.roth@amd.com> > --- > mm/memory.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/mm/memory.c b/mm/memory.c > index e68da7e403c6..33c9020ba1f8 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -4999,6 +4999,11 @@ static vm_fault_t handle_pte_fault(struct vm_fault *vmf) > static int handle_split_page_fault(struct vm_fault *vmf) > { > __split_huge_pmd(vmf->vma, vmf->pmd, vmf->address, false, NULL); > + /* > + * Install a PTE immediately to ensure that any other pages in > + * this 2MB region are brought back in as 4K pages. > + */ > + __pte_alloc(vmf->vma->vm_mm, vmf->pmd); > return 0; > } > > -- > 2.25.1
On Mon, Feb 20, 2023 at 11:57:59AM -0800, Hugh Dickins wrote: > On Mon, 20 Feb 2023, Michael Roth wrote: > > > From: Hugh Dickins <hughd@google.com> > > No. > > > > > When the address is backed by a memfd, the code to split the page does > > nothing more than remove the PMD from the page tables. So immediately > > install a PTE to ensure that any other pages in that 2MB region are > > brought back as in 4K pages. > > > > Signed-off-by: Hugh Dickins <hughd@google.com> > > No. Suggested-by would be okay. > > > Cc: Hugh Dickins <hughd@google.com> > > Thanks. I'm really sorry to be such a jobsworth, > and have nothing more constructive to say than I did before in > https://lore.kernel.org/linux-mm/7f2228c4-1586-2934-7b92-1a9d23b6046@google.com/ > (please re-read), but adding a Signed-off-by where none was given is wrong; > and I'm not ever going to comprehend enough of the context to give it. Hi Hugh, Sorry for the mix-up, I'd intended to remove this patch before submitting. I'll make sure to remove it from future postings. > > Best of luck for the series, Thank you! -Mike > Hugh > > > Signed-off-by: Ashish Kalra <ashish.kalra@amd.com> > > Signed-off-by: Michael Roth <michael.roth@amd.com> > > --- > > mm/memory.c | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/mm/memory.c b/mm/memory.c > > index e68da7e403c6..33c9020ba1f8 100644 > > --- a/mm/memory.c > > +++ b/mm/memory.c > > @@ -4999,6 +4999,11 @@ static vm_fault_t handle_pte_fault(struct vm_fault *vmf) > > static int handle_split_page_fault(struct vm_fault *vmf) > > { > > __split_huge_pmd(vmf->vma, vmf->pmd, vmf->address, false, NULL); > > + /* > > + * Install a PTE immediately to ensure that any other pages in > > + * this 2MB region are brought back in as 4K pages. > > + */ > > + __pte_alloc(vmf->vma->vm_mm, vmf->pmd); > > return 0; > > } > > > > -- > > 2.25.1
diff --git a/mm/memory.c b/mm/memory.c index e68da7e403c6..33c9020ba1f8 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4999,6 +4999,11 @@ static vm_fault_t handle_pte_fault(struct vm_fault *vmf) static int handle_split_page_fault(struct vm_fault *vmf) { __split_huge_pmd(vmf->vma, vmf->pmd, vmf->address, false, NULL); + /* + * Install a PTE immediately to ensure that any other pages in + * this 2MB region are brought back in as 4K pages. + */ + __pte_alloc(vmf->vma->vm_mm, vmf->pmd); return 0; }