This is a note to let you know that I've just added the patch titled

x86/xen: Drop 5-level paging support code from the XEN_PV code

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: x86-xen-drop-5-level-paging-support-code-from-the-xen_pv-code.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 773dd2fca581b0a80e5a33332cc8ee67e5a79cba Mon Sep 17 00:00:00 2001

From: "Kirill A. Shutemov" kirill.shutemov@linux.intel.com Date: Fri, 29 Sep 2017 17:08:20 +0300 Subject: x86/xen: Drop 5-level paging support code from the XEN_PV code

From: Kirill A. Shutemov kirill.shutemov@linux.intel.com

commit 773dd2fca581b0a80e5a33332cc8ee67e5a79cba upstream.

It was decided 5-level paging is not going to be supported in XEN_PV.

Let's drop the dead code from the XEN_PV code.

Tested-by: Juergen Gross jgross@suse.com Signed-off-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com Reviewed-by: Juergen Gross jgross@suse.com Cc: Andrew Morton akpm@linux-foundation.org Cc: Andy Lutomirski luto@amacapital.net Cc: Borislav Petkov bp@suse.de Cc: Cyrill Gorcunov gorcunov@openvz.org Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20170929140821.37654-6-kirill.shutemov@linux.intel.... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- arch/x86/xen/mmu_pv.c | 159 ++++++++++++++++++-------------------------------- 1 file changed, 60 insertions(+), 99 deletions(-)

--- a/arch/x86/xen/mmu_pv.c +++ b/arch/x86/xen/mmu_pv.c @@ -449,7 +449,7 @@ __visible pmd_t xen_make_pmd(pmdval_t pm } PV_CALLEE_SAVE_REGS_THUNK(xen_make_pmd);

-#if CONFIG_PGTABLE_LEVELS == 4 +#ifdef CONFIG_X86_64 __visible pudval_t xen_pud_val(pud_t pud) { return pte_mfn_to_pfn(pud.pud); @@ -538,7 +538,7 @@ static void xen_set_p4d(p4d_t *ptr, p4d_

xen_mc_issue(PARAVIRT_LAZY_MMU); } -#endif /* CONFIG_PGTABLE_LEVELS == 4 */ +#endif /* CONFIG_X86_64 */

static int xen_pmd_walk(struct mm_struct *mm, pmd_t *pmd, int (*func)(struct mm_struct *mm, struct page *, enum pt_level), @@ -580,21 +580,17 @@ static int xen_p4d_walk(struct mm_struct int (*func)(struct mm_struct *mm, struct page *, enum pt_level), bool last, unsigned long limit) { - int i, nr, flush = 0; + int flush = 0; + pud_t *pud;

- nr = last ? p4d_index(limit) + 1 : PTRS_PER_P4D; - for (i = 0; i < nr; i++) { - pud_t *pud;

- if (p4d_none(p4d[i])) - continue; + if (p4d_none(*p4d)) + return flush;

- pud = pud_offset(&p4d[i], 0); - if (PTRS_PER_PUD > 1) - flush |= (*func)(mm, virt_to_page(pud), PT_PUD); - flush |= xen_pud_walk(mm, pud, func, - last && i == nr - 1, limit); - } + pud = pud_offset(p4d, 0); + if (PTRS_PER_PUD > 1) + flush |= (*func)(mm, virt_to_page(pud), PT_PUD); + flush |= xen_pud_walk(mm, pud, func, last, limit); return flush; }

@@ -644,8 +640,6 @@ static int __xen_pgd_walk(struct mm_stru continue;

p4d = p4d_offset(&pgd[i], 0); - if (PTRS_PER_P4D > 1) - flush |= (*func)(mm, virt_to_page(p4d), PT_P4D); flush |= xen_p4d_walk(mm, p4d, func, i == nr - 1, limit); }

@@ -1176,22 +1170,14 @@ static void __init xen_cleanmfnmap(unsig { pgd_t *pgd; p4d_t *p4d; - unsigned int i; bool unpin;

unpin = (vaddr == 2 * PGDIR_SIZE); vaddr &= PMD_MASK; pgd = pgd_offset_k(vaddr); p4d = p4d_offset(pgd, 0); - for (i = 0; i < PTRS_PER_P4D; i++) { - if (p4d_none(p4d[i])) - continue; - xen_cleanmfnmap_p4d(p4d + i, unpin); - } - if (IS_ENABLED(CONFIG_X86_5LEVEL)) { - set_pgd(pgd, __pgd(0)); - xen_cleanmfnmap_free_pgtbl(p4d, unpin); - } + if (!p4d_none(*p4d)) + xen_cleanmfnmap_p4d(p4d, unpin); }

static void __init xen_pagetable_p2m_free(void) @@ -1692,7 +1678,7 @@ static void xen_release_pmd(unsigned lon xen_release_ptpage(pfn, PT_PMD); }

-#if CONFIG_PGTABLE_LEVELS >= 4 +#ifdef CONFIG_X86_64 static void xen_alloc_pud(struct mm_struct *mm, unsigned long pfn) { xen_alloc_ptpage(mm, pfn, PT_PUD); @@ -2029,13 +2015,12 @@ static phys_addr_t __init xen_early_virt */ void __init xen_relocate_p2m(void) { - phys_addr_t size, new_area, pt_phys, pmd_phys, pud_phys, p4d_phys; + phys_addr_t size, new_area, pt_phys, pmd_phys, pud_phys; unsigned long p2m_pfn, p2m_pfn_end, n_frames, pfn, pfn_end; - int n_pte, n_pt, n_pmd, n_pud, n_p4d, idx_pte, idx_pt, idx_pmd, idx_pud, idx_p4d; + int n_pte, n_pt, n_pmd, n_pud, idx_pte, idx_pt, idx_pmd, idx_pud; pte_t *pt; pmd_t *pmd; pud_t *pud; - p4d_t *p4d = NULL; pgd_t *pgd; unsigned long *new_p2m; int save_pud; @@ -2045,11 +2030,7 @@ void __init xen_relocate_p2m(void) n_pt = roundup(size, PMD_SIZE) >> PMD_SHIFT; n_pmd = roundup(size, PUD_SIZE) >> PUD_SHIFT; n_pud = roundup(size, P4D_SIZE) >> P4D_SHIFT; - if (PTRS_PER_P4D > 1) - n_p4d = roundup(size, PGDIR_SIZE) >> PGDIR_SHIFT; - else - n_p4d = 0; - n_frames = n_pte + n_pt + n_pmd + n_pud + n_p4d; + n_frames = n_pte + n_pt + n_pmd + n_pud;

new_area = xen_find_free_area(PFN_PHYS(n_frames)); if (!new_area) { @@ -2065,76 +2046,56 @@ void __init xen_relocate_p2m(void) * To avoid any possible virtual address collision, just use * 2 * PUD_SIZE for the new area. */ - p4d_phys = new_area; - pud_phys = p4d_phys + PFN_PHYS(n_p4d); + pud_phys = new_area; pmd_phys = pud_phys + PFN_PHYS(n_pud); pt_phys = pmd_phys + PFN_PHYS(n_pmd); p2m_pfn = PFN_DOWN(pt_phys) + n_pt;

pgd = __va(read_cr3_pa()); new_p2m = (unsigned long *)(2 * PGDIR_SIZE); - idx_p4d = 0; save_pud = n_pud; - do { - if (n_p4d > 0) { - p4d = early_memremap(p4d_phys, PAGE_SIZE); - clear_page(p4d); - n_pud = min(save_pud, PTRS_PER_P4D); - } - for (idx_pud = 0; idx_pud < n_pud; idx_pud++) { - pud = early_memremap(pud_phys, PAGE_SIZE); - clear_page(pud); - for (idx_pmd = 0; idx_pmd < min(n_pmd, PTRS_PER_PUD); - idx_pmd++) { - pmd = early_memremap(pmd_phys, PAGE_SIZE); - clear_page(pmd); - for (idx_pt = 0; idx_pt < min(n_pt, PTRS_PER_PMD); - idx_pt++) { - pt = early_memremap(pt_phys, PAGE_SIZE); - clear_page(pt); - for (idx_pte = 0; - idx_pte < min(n_pte, PTRS_PER_PTE); - idx_pte++) { - set_pte(pt + idx_pte, - pfn_pte(p2m_pfn, PAGE_KERNEL)); - p2m_pfn++; - } - n_pte -= PTRS_PER_PTE; - early_memunmap(pt, PAGE_SIZE); - make_lowmem_page_readonly(__va(pt_phys)); - pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, - PFN_DOWN(pt_phys)); - set_pmd(pmd + idx_pt, - __pmd(_PAGE_TABLE | pt_phys)); - pt_phys += PAGE_SIZE; + for (idx_pud = 0; idx_pud < n_pud; idx_pud++) { + pud = early_memremap(pud_phys, PAGE_SIZE); + clear_page(pud); + for (idx_pmd = 0; idx_pmd < min(n_pmd, PTRS_PER_PUD); + idx_pmd++) { + pmd = early_memremap(pmd_phys, PAGE_SIZE); + clear_page(pmd); + for (idx_pt = 0; idx_pt < min(n_pt, PTRS_PER_PMD); + idx_pt++) { + pt = early_memremap(pt_phys, PAGE_SIZE); + clear_page(pt); + for (idx_pte = 0; + idx_pte < min(n_pte, PTRS_PER_PTE); + idx_pte++) { + set_pte(pt + idx_pte, + pfn_pte(p2m_pfn, PAGE_KERNEL)); + p2m_pfn++; } - n_pt -= PTRS_PER_PMD; - early_memunmap(pmd, PAGE_SIZE); - make_lowmem_page_readonly(__va(pmd_phys)); - pin_pagetable_pfn(MMUEXT_PIN_L2_TABLE, - PFN_DOWN(pmd_phys)); - set_pud(pud + idx_pmd, __pud(_PAGE_TABLE | pmd_phys)); - pmd_phys += PAGE_SIZE; + n_pte -= PTRS_PER_PTE; + early_memunmap(pt, PAGE_SIZE); + make_lowmem_page_readonly(__va(pt_phys)); + pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, + PFN_DOWN(pt_phys)); + set_pmd(pmd + idx_pt, + __pmd(_PAGE_TABLE | pt_phys)); + pt_phys += PAGE_SIZE; } - n_pmd -= PTRS_PER_PUD; - early_memunmap(pud, PAGE_SIZE); - make_lowmem_page_readonly(__va(pud_phys)); - pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, PFN_DOWN(pud_phys)); - if (n_p4d > 0) - set_p4d(p4d + idx_pud, __p4d(_PAGE_TABLE | pud_phys)); - else - set_pgd(pgd + 2 + idx_pud, __pgd(_PAGE_TABLE | pud_phys)); - pud_phys += PAGE_SIZE; - } - if (n_p4d > 0) { - save_pud -= PTRS_PER_P4D; - early_memunmap(p4d, PAGE_SIZE); - make_lowmem_page_readonly(__va(p4d_phys)); - pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE, PFN_DOWN(p4d_phys)); - set_pgd(pgd + 2 + idx_p4d, __pgd(_PAGE_TABLE | p4d_phys)); - p4d_phys += PAGE_SIZE; + n_pt -= PTRS_PER_PMD; + early_memunmap(pmd, PAGE_SIZE); + make_lowmem_page_readonly(__va(pmd_phys)); + pin_pagetable_pfn(MMUEXT_PIN_L2_TABLE, + PFN_DOWN(pmd_phys)); + set_pud(pud + idx_pmd, __pud(_PAGE_TABLE | pmd_phys)); + pmd_phys += PAGE_SIZE; } - } while (++idx_p4d < n_p4d); + n_pmd -= PTRS_PER_PUD; + early_memunmap(pud, PAGE_SIZE); + make_lowmem_page_readonly(__va(pud_phys)); + pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, PFN_DOWN(pud_phys)); + set_pgd(pgd + 2 + idx_pud, __pgd(_PAGE_TABLE | pud_phys)); + pud_phys += PAGE_SIZE; + }

/* Now copy the old p2m info to the new area. */ memcpy(new_p2m, xen_p2m_addr, size); @@ -2361,7 +2322,7 @@ static void __init xen_post_allocator_in pv_mmu_ops.set_pte = xen_set_pte; pv_mmu_ops.set_pmd = xen_set_pmd; pv_mmu_ops.set_pud = xen_set_pud; -#if CONFIG_PGTABLE_LEVELS >= 4 +#ifdef CONFIG_X86_64 pv_mmu_ops.set_p4d = xen_set_p4d; #endif

@@ -2371,7 +2332,7 @@ static void __init xen_post_allocator_in pv_mmu_ops.alloc_pmd = xen_alloc_pmd; pv_mmu_ops.release_pte = xen_release_pte; pv_mmu_ops.release_pmd = xen_release_pmd; -#if CONFIG_PGTABLE_LEVELS >= 4 +#ifdef CONFIG_X86_64 pv_mmu_ops.alloc_pud = xen_alloc_pud; pv_mmu_ops.release_pud = xen_release_pud; #endif @@ -2435,14 +2396,14 @@ static const struct pv_mmu_ops xen_mmu_o .make_pmd = PV_CALLEE_SAVE(xen_make_pmd), .pmd_val = PV_CALLEE_SAVE(xen_pmd_val),

-#if CONFIG_PGTABLE_LEVELS >= 4 +#ifdef CONFIG_X86_64 .pud_val = PV_CALLEE_SAVE(xen_pud_val), .make_pud = PV_CALLEE_SAVE(xen_make_pud), .set_p4d = xen_set_p4d_hyper,

.alloc_pud = xen_alloc_pmd_init, .release_pud = xen_release_pmd_init, -#endif /* CONFIG_PGTABLE_LEVELS == 4 */ +#endif /* CONFIG_X86_64 */

.activate_mm = xen_activate_mm, .dup_mmap = xen_dup_mmap,

Patches currently in stable-queue which might be from kirill.shutemov@linux.intel.com are

queue-4.14/x86-xen-provide-pre-built-page-tables-only-for-config_xen_pv-y-and-config_xen_pvh-y.patch queue-4.14/x86-xen-drop-5-level-paging-support-code-from-the-xen_pv-code.patch queue-4.14/x86-kasan-use-the-same-shadow-offset-for-4-and-5-level-paging.patch queue-4.14/mm-sparsemem-allocate-mem_section-at-runtime-for-config_sparsemem_extreme-y.patch queue-4.14/x86-mm-relocate-page-fault-error-codes-to-traps.h.patch