x86/mm: Recompute physical address for every page of per-CPU CEA mapping

jira VULN-8044
cve-bf CVE-2023-0597
commit-author Sean Christopherson <[email protected]>
commit 80d72a8

Recompute the physical address for each per-CPU page in the CPU entry
area, a recent commit inadvertantly modified cea_map_percpu_pages() such
that every PTE is mapped to the physical address of the first page.

Fixes: 9fd429c28073 ("x86/kasan: Map shadow for percpu pages on demand")
	Signed-off-by: Sean Christopherson <[email protected]>
	Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
	Reviewed-by: Andrey Ryabinin <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
(cherry picked from commit 80d72a8)
	Signed-off-by: Marcin Wcisło <[email protected]>

Author: pvts-mat

arch/x86/mm/cpu_entry_area.c

@@ -98,7 +98,7 @@ cea_map_percpu_pages(void *cea_vaddr, void *ptr, int pages, pgprot_t prot)
 					early_pfn_to_nid(PFN_DOWN(pa)));
 
 	for ( ; pages; pages--, cea_vaddr+= PAGE_SIZE, ptr += PAGE_SIZE)
-		cea_set_pte(cea_vaddr, pa, prot);
+		cea_set_pte(cea_vaddr, per_cpu_ptr_to_phys(ptr), prot);
 }
 
 static void __init percpu_setup_debug_store(unsigned int cpu)