From c9b5ad546e7d486465a3dd8c89245ac3707a4384 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Tue, 14 Jun 2016 12:56:01 +0200 Subject: s390/mm: tag normal pages vs pages used in page tables The ESSA instruction has a new option that allows to tag pages that are not used as a page table. Without the tag the hypervisor has to assume that any guest page could be used in a page table inside the guest. This forces the hypervisor to flush all guest TLB entries whenever a host page table entry is invalidated. With the tag the host can skip the TLB flush if the page is tagged as normal page. Signed-off-by: Martin Schwidefsky --- arch/s390/mm/page-states.c | 192 +++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 177 insertions(+), 15 deletions(-) (limited to 'arch/s390/mm/page-states.c') diff --git a/arch/s390/mm/page-states.c b/arch/s390/mm/page-states.c index 69a7b01ae746..07fa7b8ae233 100644 --- a/arch/s390/mm/page-states.c +++ b/arch/s390/mm/page-states.c @@ -10,9 +10,10 @@ #include #include #include +#include #include #include - +#include #include static int cmma_flag = 1; @@ -36,14 +37,16 @@ __setup("cmma=", cmma); static inline int cmma_test_essa(void) { register unsigned long tmp asm("0") = 0; - register int rc asm("1") = -EOPNOTSUPP; + register int rc asm("1"); + /* test ESSA_GET_STATE */ asm volatile( - " .insn rrf,0xb9ab0000,%1,%1,0,0\n" + " .insn rrf,0xb9ab0000,%1,%1,%2,0\n" "0: la %0,0\n" "1:\n" EX_TABLE(0b,1b) - : "+&d" (rc), "+&d" (tmp)); + : "=&d" (rc), "+&d" (tmp) + : "i" (ESSA_GET_STATE), "0" (-EOPNOTSUPP)); return rc; } @@ -51,11 +54,26 @@ void __init cmma_init(void) { if (!cmma_flag) return; - if (cmma_test_essa()) + if (cmma_test_essa()) { cmma_flag = 0; + return; + } + if (test_facility(147)) + cmma_flag = 2; } -static inline void set_page_unstable(struct page *page, int order) +static inline unsigned char get_page_state(struct page *page) +{ + unsigned char state; + + asm volatile(" .insn rrf,0xb9ab0000,%0,%1,%2,0" + : "=&d" (state) + : "a" (page_to_phys(page)), + "i" (ESSA_GET_STATE)); + return state & 0x3f; +} + +static inline void set_page_unused(struct page *page, int order) { int i, rc; @@ -66,14 +84,18 @@ static inline void set_page_unstable(struct page *page, int order) "i" (ESSA_SET_UNUSED)); } -void arch_free_page(struct page *page, int order) +static inline void set_page_stable_dat(struct page *page, int order) { - if (!cmma_flag) - return; - set_page_unstable(page, order); + int i, rc; + + for (i = 0; i < (1 << order); i++) + asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0" + : "=&d" (rc) + : "a" (page_to_phys(page + i)), + "i" (ESSA_SET_STABLE)); } -static inline void set_page_stable(struct page *page, int order) +static inline void set_page_stable_nodat(struct page *page, int order) { int i, rc; @@ -81,14 +103,154 @@ static inline void set_page_stable(struct page *page, int order) asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0" : "=&d" (rc) : "a" (page_to_phys(page + i)), - "i" (ESSA_SET_STABLE)); + "i" (ESSA_SET_STABLE_NODAT)); +} + +static void mark_kernel_pmd(pud_t *pud, unsigned long addr, unsigned long end) +{ + unsigned long next; + struct page *page; + pmd_t *pmd; + + pmd = pmd_offset(pud, addr); + do { + next = pmd_addr_end(addr, end); + if (pmd_none(*pmd) || pmd_large(*pmd)) + continue; + page = virt_to_page(pmd_val(*pmd)); + set_bit(PG_arch_1, &page->flags); + } while (pmd++, addr = next, addr != end); +} + +static void mark_kernel_pud(p4d_t *p4d, unsigned long addr, unsigned long end) +{ + unsigned long next; + struct page *page; + pud_t *pud; + int i; + + pud = pud_offset(p4d, addr); + do { + next = pud_addr_end(addr, end); + if (pud_none(*pud) || pud_large(*pud)) + continue; + if (!pud_folded(*pud)) { + page = virt_to_page(pud_val(*pud)); + for (i = 0; i < 3; i++) + set_bit(PG_arch_1, &page[i].flags); + } + mark_kernel_pmd(pud, addr, next); + } while (pud++, addr = next, addr != end); +} + +static void mark_kernel_p4d(pgd_t *pgd, unsigned long addr, unsigned long end) +{ + unsigned long next; + struct page *page; + p4d_t *p4d; + int i; + + p4d = p4d_offset(pgd, addr); + do { + next = p4d_addr_end(addr, end); + if (p4d_none(*p4d)) + continue; + if (!p4d_folded(*p4d)) { + page = virt_to_page(p4d_val(*p4d)); + for (i = 0; i < 3; i++) + set_bit(PG_arch_1, &page[i].flags); + } + mark_kernel_pud(p4d, addr, next); + } while (p4d++, addr = next, addr != end); +} + +static void mark_kernel_pgd(void) +{ + unsigned long addr, next; + struct page *page; + pgd_t *pgd; + int i; + + addr = 0; + pgd = pgd_offset_k(addr); + do { + next = pgd_addr_end(addr, MODULES_END); + if (pgd_none(*pgd)) + continue; + if (!pgd_folded(*pgd)) { + page = virt_to_page(pgd_val(*pgd)); + for (i = 0; i < 3; i++) + set_bit(PG_arch_1, &page[i].flags); + } + mark_kernel_p4d(pgd, addr, next); + } while (pgd++, addr = next, addr != MODULES_END); +} + +void __init cmma_init_nodat(void) +{ + struct memblock_region *reg; + struct page *page; + unsigned long start, end, ix; + + if (cmma_flag < 2) + return; + /* Mark pages used in kernel page tables */ + mark_kernel_pgd(); + + /* Set all kernel pages not used for page tables to stable/no-dat */ + for_each_memblock(memory, reg) { + start = memblock_region_memory_base_pfn(reg); + end = memblock_region_memory_end_pfn(reg); + page = pfn_to_page(start); + for (ix = start; ix < end; ix++, page++) { + if (__test_and_clear_bit(PG_arch_1, &page->flags)) + continue; /* skip page table pages */ + if (!list_empty(&page->lru)) + continue; /* skip free pages */ + set_page_stable_nodat(page, 0); + } + } +} + +void arch_free_page(struct page *page, int order) +{ + if (!cmma_flag) + return; + set_page_unused(page, order); } void arch_alloc_page(struct page *page, int order) { if (!cmma_flag) return; - set_page_stable(page, order); + if (cmma_flag < 2) + set_page_stable_dat(page, order); + else + set_page_stable_nodat(page, order); +} + +void arch_set_page_dat(struct page *page, int order) +{ + if (!cmma_flag) + return; + set_page_stable_dat(page, order); +} + +void arch_set_page_nodat(struct page *page, int order) +{ + if (cmma_flag < 2) + return; + set_page_stable_nodat(page, order); +} + +int arch_test_page_nodat(struct page *page) +{ + unsigned char state; + + if (cmma_flag < 2) + return 0; + state = get_page_state(page); + return !!(state & 0x20); } void arch_set_page_states(int make_stable) @@ -108,9 +270,9 @@ void arch_set_page_states(int make_stable) list_for_each(l, &zone->free_area[order].free_list[t]) { page = list_entry(l, struct page, lru); if (make_stable) - set_page_stable(page, order); + set_page_stable_dat(page, 0); else - set_page_unstable(page, order); + set_page_unused(page, order); } } spin_unlock_irqrestore(&zone->lock, flags); -- cgit v1.2.3