| Message ID | 20190508144422.13171-21-kirill.shutemov@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Intel MKTME enabling | expand |
On Wed, May 08, 2019 at 05:43:40PM +0300, Kirill A. Shutemov wrote: > page_keyid() is inline funcation that uses lookup_page_ext(). KVM is > going to use page_keyid() and since KVM can be built as a module > lookup_page_ext() has to be exported. I _really_ hate having to export world+dog for KVM. This one might not be a real issue, but I itch every time I see an export for KVM these days.
On Fri, Jun 14, 2019 at 01:12:59PM +0200, Peter Zijlstra wrote: > On Wed, May 08, 2019 at 05:43:40PM +0300, Kirill A. Shutemov wrote: > > page_keyid() is inline funcation that uses lookup_page_ext(). KVM is > > going to use page_keyid() and since KVM can be built as a module > > lookup_page_ext() has to be exported. > > I _really_ hate having to export world+dog for KVM. This one might not > be a real issue, but I itch every time I see an export for KVM these > days. Is there any better way? Do we need to invent EXPORT_SYMBOL_KVM()? :P
On Sat, Jun 15, 2019 at 01:44:43AM +0300, Kirill A. Shutemov wrote: > On Fri, Jun 14, 2019 at 01:12:59PM +0200, Peter Zijlstra wrote: > > On Wed, May 08, 2019 at 05:43:40PM +0300, Kirill A. Shutemov wrote: > > > page_keyid() is inline funcation that uses lookup_page_ext(). KVM is > > > going to use page_keyid() and since KVM can be built as a module > > > lookup_page_ext() has to be exported. > > > > I _really_ hate having to export world+dog for KVM. This one might not > > be a real issue, but I itch every time I see an export for KVM these > > days. > > Is there any better way? Do we need to invent EXPORT_SYMBOL_KVM()? :P Or disallow KVM (or parts thereof) from being a module anymore.
On Mon, 2019-06-17 at 11:30 +0200, Peter Zijlstra wrote: > On Sat, Jun 15, 2019 at 01:44:43AM +0300, Kirill A. Shutemov wrote: > > On Fri, Jun 14, 2019 at 01:12:59PM +0200, Peter Zijlstra wrote: > > > On Wed, May 08, 2019 at 05:43:40PM +0300, Kirill A. Shutemov wrote: > > > > page_keyid() is inline funcation that uses lookup_page_ext(). KVM is > > > > going to use page_keyid() and since KVM can be built as a module > > > > lookup_page_ext() has to be exported. > > > > > > I _really_ hate having to export world+dog for KVM. This one might not > > > be a real issue, but I itch every time I see an export for KVM these > > > days. > > > > Is there any better way? Do we need to invent EXPORT_SYMBOL_KVM()? :P > > Or disallow KVM (or parts thereof) from being a module anymore. For this particular symbol expose, I don't think its fair to blame KVM since the fundamental reason is because page_keyid() (which calls lookup_page_ext()) being implemented as static inline function in header file, so essentially having any other module who calls page_keyid() will trigger this problem -- in fact IOMMU driver calls page_keyid() too so even w/o KVM lookup_page_ext() needs to be exposed. Thanks, -Kai
On Mon, 2019-06-17 at 23:01 +1200, Kai Huang wrote: > On Mon, 2019-06-17 at 11:30 +0200, Peter Zijlstra wrote: > > On Sat, Jun 15, 2019 at 01:44:43AM +0300, Kirill A. Shutemov wrote: > > > On Fri, Jun 14, 2019 at 01:12:59PM +0200, Peter Zijlstra wrote: > > > > On Wed, May 08, 2019 at 05:43:40PM +0300, Kirill A. Shutemov wrote: > > > > > page_keyid() is inline funcation that uses lookup_page_ext(). KVM is > > > > > going to use page_keyid() and since KVM can be built as a module > > > > > lookup_page_ext() has to be exported. > > > > > > > > I _really_ hate having to export world+dog for KVM. This one might not > > > > be a real issue, but I itch every time I see an export for KVM these > > > > days. > > > > > > Is there any better way? Do we need to invent EXPORT_SYMBOL_KVM()? :P > > > > Or disallow KVM (or parts thereof) from being a module anymore. > > For this particular symbol expose, I don't think its fair to blame KVM since the fundamental > reason > is because page_keyid() (which calls lookup_page_ext()) being implemented as static inline > function > in header file, so essentially having any other module who calls page_keyid() will trigger this > problem -- in fact IOMMU driver calls page_keyid() too so even w/o KVM lookup_page_ext() needs to > be > exposed. Oops it seems Intel IOMMU driver is not a module but buildin so yes KVM is the only module who calls page_keyid() now. Sorry my bad. But if there's any other module calls page_keyid(), this patch is required. Thanks, -Kai > > Thanks, > -Kai >
diff --git a/mm/page_ext.c b/mm/page_ext.c index 1af8b82087f2..91e4e87f6e41 100644 --- a/mm/page_ext.c +++ b/mm/page_ext.c @@ -142,6 +142,7 @@ struct page_ext *lookup_page_ext(const struct page *page) MAX_ORDER_NR_PAGES); return get_entry(base, index); } +EXPORT_SYMBOL_GPL(lookup_page_ext); static int __init alloc_node_page_ext(int nid) { @@ -212,6 +213,7 @@ struct page_ext *lookup_page_ext(const struct page *page) return NULL; return get_entry(section->page_ext, pfn); } +EXPORT_SYMBOL_GPL(lookup_page_ext); static void *__meminit alloc_page_ext(size_t size, int nid) {
page_keyid() is inline funcation that uses lookup_page_ext(). KVM is going to use page_keyid() and since KVM can be built as a module lookup_page_ext() has to be exported. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> --- mm/page_ext.c | 2 ++ 1 file changed, 2 insertions(+)