Commit-ID:  773dd2fca581b0a80e5a33332cc8ee67e5a79cba
Gitweb:     https://git.kernel.org/tip/773dd2fca581b0a80e5a33332cc8ee67e5a79cba
Author:     Kirill A. Shutemov <kirill.shute...@linux.intel.com>
AuthorDate: Fri, 29 Sep 2017 17:08:20 +0300
Committer:  Ingo Molnar <mi...@kernel.org>
CommitDate: Fri, 20 Oct 2017 13:07:10 +0200

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

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 <jgr...@suse.com>
Signed-off-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com>
Reviewed-by: Juergen Gross <jgr...@suse.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Andy Lutomirski <l...@amacapital.net>
Cc: Borislav Petkov <b...@suse.de>
Cc: Cyrill Gorcunov <gorcu...@openvz.org>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: linux...@kvack.org
Link: 
http://lkml.kernel.org/r/20170929140821.37654-6-kirill.shute...@linux.intel.com
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
 arch/x86/xen/mmu_pv.c | 159 +++++++++++++++++++-------------------------------
 1 file changed, 60 insertions(+), 99 deletions(-)

diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index 71495f1..2ccdaba 100644
--- 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 pmd)
 }
 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_t val)
 
        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 *mm, p4d_t *p4d,
                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_struct *mm, pgd_t *pgd,
                        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(unsigned long vaddr)
 {
        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 long pfn)
        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_to_phys(unsigned long vaddr)
  */
 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_init(void)
        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_init(void)
        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_ops __initconst 
= {
        .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,

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