| Message ID | 20240418194133.1452059-5-michael.roth@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support | expand |
On 18.04.24 21:41, Michael Roth wrote: > kvm_gmem_get_folio() may return a PTR_ERR() rather than just NULL. In > particular, for cases where EEXISTS is returned when FGP_CREAT_ONLY > flag is used. Handle this properly in __kvm_gmem_get_pfn(). > > Signed-off-by: Michael Roth <michael.roth@amd.com> > --- > virt/kvm/guest_memfd.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c > index ccf22e44f387..9d7c6a70c547 100644 > --- a/virt/kvm/guest_memfd.c > +++ b/virt/kvm/guest_memfd.c > @@ -580,8 +580,8 @@ static int __kvm_gmem_get_pfn(struct file *file, struct kvm_memory_slot *slot, > } > > folio = kvm_gmem_get_folio(file_inode(file), index, prepare); > - if (!folio) > - return -ENOMEM; > + if (IS_ERR_OR_NULL(folio)) > + return folio ? PTR_ERR(folio) : -ENOMEM; Will it even return NULL? Staring at other filemap_grab_folio() users, they all check for IS_ERR(). > > if (folio_test_hwpoison(folio)) { > r = -EHWPOISON; Do we have a Fixes: tag?
On Fri, Apr 19, 2024 at 02:58:43PM +0200, David Hildenbrand wrote: > On 18.04.24 21:41, Michael Roth wrote: > > kvm_gmem_get_folio() may return a PTR_ERR() rather than just NULL. In > > particular, for cases where EEXISTS is returned when FGP_CREAT_ONLY > > flag is used. Handle this properly in __kvm_gmem_get_pfn(). > > > > Signed-off-by: Michael Roth <michael.roth@amd.com> > > --- > > virt/kvm/guest_memfd.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c > > index ccf22e44f387..9d7c6a70c547 100644 > > --- a/virt/kvm/guest_memfd.c > > +++ b/virt/kvm/guest_memfd.c > > @@ -580,8 +580,8 @@ static int __kvm_gmem_get_pfn(struct file *file, struct kvm_memory_slot *slot, > > } > > folio = kvm_gmem_get_folio(file_inode(file), index, prepare); > > - if (!folio) > > - return -ENOMEM; > > + if (IS_ERR_OR_NULL(folio)) > > + return folio ? PTR_ERR(folio) : -ENOMEM; > > Will it even return NULL? Staring at other filemap_grab_folio() users, they > all check for IS_ERR(). Looks like the NULL case is handled with PTR_ERR(-ENOENT), so IS_ERR() would be sufficient. I think in the past kvm_gmem_get_folio() itself would return NULL in some cases, but as of commit 2b01b7e994e95 that's no longer the case. I'll fix this up to expect only PTR_ERR() when I re-spin v14, and also address the other kvm_gmem_get_folio() / __filemap_get_folio() call sites. > > > if (folio_test_hwpoison(folio)) { > > r = -EHWPOISON; > > Do we have a Fixes: tag? Fixes: 2b01b7e994e95 ("KVM: guest_memfd: pass error up from filemap_grab_folio") Will add that in the re-spin as well. Thanks! -Mike > > -- > Cheers, > > David / dhildenb >
On Fri, Apr 19, 2024 at 5:11 PM Michael Roth <michael.roth@amd.com> wrote: > > On Fri, Apr 19, 2024 at 02:58:43PM +0200, David Hildenbrand wrote: > > On 18.04.24 21:41, Michael Roth wrote: > > > kvm_gmem_get_folio() may return a PTR_ERR() rather than just NULL. In > > > particular, for cases where EEXISTS is returned when FGP_CREAT_ONLY > > > flag is used. Handle this properly in __kvm_gmem_get_pfn(). > > > > > > Signed-off-by: Michael Roth <michael.roth@amd.com> > > > --- > > > virt/kvm/guest_memfd.c | 4 ++-- > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c > > > index ccf22e44f387..9d7c6a70c547 100644 > > > --- a/virt/kvm/guest_memfd.c > > > +++ b/virt/kvm/guest_memfd.c > > > @@ -580,8 +580,8 @@ static int __kvm_gmem_get_pfn(struct file *file, struct kvm_memory_slot *slot, > > > } > > > folio = kvm_gmem_get_folio(file_inode(file), index, prepare); > > > - if (!folio) > > > - return -ENOMEM; > > > + if (IS_ERR_OR_NULL(folio)) > > > + return folio ? PTR_ERR(folio) : -ENOMEM; > > > > Will it even return NULL? Staring at other filemap_grab_folio() users, they > > all check for IS_ERR(). > > Looks like the NULL case is handled with PTR_ERR(-ENOENT), so IS_ERR() > would be sufficient. I think in the past kvm_gmem_get_folio() itself > would return NULL in some cases, but as of commit 2b01b7e994e95 that's > no longer the case. > > I'll fix this up to expect only PTR_ERR() when I re-spin v14, and also > address the other kvm_gmem_get_folio() / __filemap_get_folio() call > sites. > > > > > > if (folio_test_hwpoison(folio)) { > > > r = -EHWPOISON; > > > > Do we have a Fixes: tag? > > Fixes: 2b01b7e994e95 ("KVM: guest_memfd: pass error up from filemap_grab_folio") I'll squash it so when you rebase on the new kvm-coco-queue it will go away. Thanks to both! Paolo
diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index ccf22e44f387..9d7c6a70c547 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -580,8 +580,8 @@ static int __kvm_gmem_get_pfn(struct file *file, struct kvm_memory_slot *slot, } folio = kvm_gmem_get_folio(file_inode(file), index, prepare); - if (!folio) - return -ENOMEM; + if (IS_ERR_OR_NULL(folio)) + return folio ? PTR_ERR(folio) : -ENOMEM; if (folio_test_hwpoison(folio)) { r = -EHWPOISON;
kvm_gmem_get_folio() may return a PTR_ERR() rather than just NULL. In particular, for cases where EEXISTS is returned when FGP_CREAT_ONLY flag is used. Handle this properly in __kvm_gmem_get_pfn(). Signed-off-by: Michael Roth <michael.roth@amd.com> --- virt/kvm/guest_memfd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)