On Wed, Nov 02, 2022 at 09:48:47AM -0700, Stanislav Kinsburskiy wrote:

quoted

quoted

diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 311eae30e089..6976416b2c9f 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c

@@ -210,11 +210,10 @@ static vm_fault_t vvar_fault(const struct

vm_special_mapping *sm,

quoted

 pgprot_decrypted(vma->vm_page_prot));

quoted

              }
      } else if (sym_offset == image->sym_hvclock_page) {
-             struct ms_hyperv_tsc_page *tsc_pg = hv_get_tsc_page();
+             pfn = hv_get_tsc_pfn();

-             if (tsc_pg && vclock_was_used(VDSO_CLOCKMODE_HVCLOCK))
-                     return vmf_insert_pfn(vma, vmf->address,
-                                     virt_to_phys(tsc_pg) >>

PAGE_SHIFT);

quoted

+             if (pfn && vclock_was_used(VDSO_CLOCKMODE_HVCLOCK))
+                     return vmf_insert_pfn(vma, vmf->address, pfn);

hv_get_tsc_pfn() can return 0. You will insert PFN 0 into the page
table. I think you should check if the PFN is valid.

I'm confused. Isn't "if (pfn &&" checks for non-zero value?

I misread. The code is fine.

Wei.