[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH] x86/mm: Skip the hypervisor range when walking PGD
The range between 0xffff800000000000 and 0xffff87ffffffffff is reserved for hypervisor and therefore we should not try to follow PGD's indexes corresponding to those addresses. While this has alsways been a problem, with commit e1a58320a38d ("x86/mm: Warn on W^X mappings") ptdump_walk_pgd_level_core() can now be called during boot, causing a PV Xen guest to crash. Reported-by: Sander Eikelenboom <linux@xxxxxxxxxxxxxx> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> --- arch/x86/mm/dump_pagetables.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c index 1bf417e..756c921 100644 --- a/arch/x86/mm/dump_pagetables.c +++ b/arch/x86/mm/dump_pagetables.c @@ -362,8 +362,13 @@ static void ptdump_walk_pgd_level_core(struct seq_file *m, pgd_t *pgd, bool checkwx) { #ifdef CONFIG_X86_64 +/* ffff800000000000 - ffff87ffffffffff is reserved for hypervisor */ +#define is_hypervisor_range(idx) (paravirt_enabled() && \ + (((idx) >= pgd_index(__PAGE_OFFSET) - 16) && \ + ((idx) < pgd_index(__PAGE_OFFSET)))) pgd_t *start = (pgd_t *) &init_level4_pgt; #else +#define is_hypervisor_range(idx) 0 pgd_t *start = swapper_pg_dir; #endif pgprotval_t prot; @@ -381,7 +386,7 @@ static void ptdump_walk_pgd_level_core(struct seq_file *m, pgd_t *pgd, for (i = 0; i < PTRS_PER_PGD; i++) { st.current_address = normalize_addr(i * PGD_LEVEL_MULT); - if (!pgd_none(*start)) { + if (!pgd_none(*start) && !is_hypervisor_range(i)) { if (pgd_large(*start) || !pgd_present(*start)) { prot = pgd_flags(*start); note_page(m, &st, __pgprot(prot), 1); -- 1.9.3 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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