[Qemu-devel] [PATCH 21/40] xenner: kernel: mmu support for 32-bit normal

[Alexander Graf <agraf@suse.de>]

This patch adds support for memory management on 32 bit systems without PAE.

Signed-off-by: Alexander Graf <agraf@suse.de>
---
 pc-bios/xenner/xenner-mm32.c |  314 ++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 314 insertions(+), 0 deletions(-)
 create mode 100644 pc-bios/xenner/xenner-mm32.c

diff --git a/pc-bios/xenner/xenner-mm32.c b/pc-bios/xenner/xenner-mm32.c
new file mode 100644
index 0000000..7622ae5
--- /dev/null
+++ b/pc-bios/xenner/xenner-mm32.c
@@ -0,0 +1,314 @@
+/*
+ *  Copyright (C) Red Hat 2007
+ *  Copyright (C) Novell Inc. 2010
+ *
+ *  Author(s): Gerd Hoffmann <kraxel@redhat.com>
+ *             Alexander Graf <agraf@suse.de>
+ *
+ *  Xenner memory management for 32 bit normal mode
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; under version 2 of the License.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <inttypes.h>
+#include <xen/xen.h>
+
+#include "xenner.h"
+#include "xenner-mm.c"
+
+/* --------------------------------------------------------------------- */
+
+#define MAPS_R_BITS        4
+#define MAPS_R_COUNT       (1 << MAPS_R_BITS)
+#define MAPS_R_MASK        (MAPS_R_COUNT - 1)
+#define MAPS_R_SIZE        (MAPS_MAX / MAPS_R_COUNT)
+#define MAPS_R_LOW(r)      (MAPS_R_SIZE * (r))
+#define MAPS_R_HIGH(r)     (MAPS_R_SIZE * (r) + MAPS_R_SIZE)
+static int maps_next[MAPS_R_COUNT];
+
+static spinlock_t maplock = SPIN_LOCK_UNLOCKED;
+
+/* --------------------------------------------------------------------- */
+
+uintptr_t emu_pa(uintptr_t va)
+{
+    switch(va & 0xfff00000) {
+    case XEN_TXT:
+        return va - (uintptr_t)_vstart;
+    case XEN_IPT:
+    {
+        uintptr_t mfn_guest = emudev_get(EMUDEV_CONF_GUEST_START_PFN, 0);
+        uintptr_t init_pt_pfn = emudev_get(EMUDEV_CONF_PFN_INIT_PT, 0);
+
+        return frame_to_addr(mfn_guest + init_pt_pfn) | (va - XEN_IPT);
+    }
+    case XEN_M2P:
+        return va - XEN_M2P + frame_to_addr(vmconf.mfn_m2p);
+    }
+
+    panic("unknown address", NULL);
+    return 0;
+}
+
+/* --------------------------------------------------------------------- */
+
+static int find_slot(int range)
+{
+    int low   = MAPS_R_LOW(range);
+    int high  = MAPS_R_HIGH(range);
+    int *next = maps_next + range;
+    int start = *next;
+    int slot;
+
+    while (maps_refcnt[*next]) {
+        (*next)++;
+        if (*next == high) {
+            *next = low;
+        }
+        if (*next == start) {
+            return -1;
+        }
+    }
+    slot = *next;
+    (*next)++;
+    if (*next == high) {
+        *next = low;
+    }
+    return slot;
+}
+
+static int mfn_to_slot_32(uint32_t mfn, int range)
+{
+    int low   = MAPS_R_LOW(range);
+    int high  = MAPS_R_HIGH(range);
+    int slot;
+
+    for (slot = low; slot < high; slot++) {
+        if (!test_pgflag_32(maps_32[slot], _PAGE_PRESENT)) {
+            continue;
+        }
+        if (get_pgframe_32(maps_32[slot]) == mfn) {
+            /* cache hit */
+            return slot;
+        }
+    }
+    return -1;
+}
+
+void *map_page(unsigned long maddr)
+{
+    uint32_t mfn = addr_to_frame(maddr);
+    uint32_t off = addr_offset(maddr);
+    uint32_t va;
+    int range, slot;
+
+    spin_lock(&maplock);
+    range = mfn & MAPS_R_MASK;
+    slot = mfn_to_slot_32(mfn, range);
+    if (slot == -1) {
+        slot = find_slot(range);
+        if (slot == -1) {
+            panic("out of map slots", NULL);
+        }
+        printk(3, "%s: mfn %5x range %d [%3d - %3d], slot %3d\n", __FUNCTION__,
+               mfn, range, MAPS_R_LOW(range), MAPS_R_HIGH(range), slot);
+        maps_32[slot] = get_pgentry_32(mfn, EMU_PGFLAGS);
+        vminfo.faults[XEN_FAULT_MAPS_MAPIT]++;
+        va = XEN_MAP_32 + slot*PAGE_SIZE;
+        flush_tlb_addr(va);
+    } else {
+        printk(3, "%s: mfn %5x range %d [%3d - %3d], slot %3d (cached)\n",
+               __FUNCTION__, mfn, range, MAPS_R_LOW(range), MAPS_R_HIGH(range),
+               slot);
+        vminfo.faults[XEN_FAULT_MAPS_REUSE]++;
+        va = XEN_MAP_32 + slot*PAGE_SIZE;
+    }
+    maps_refcnt[slot]++;
+    spin_unlock(&maplock);
+
+    return (void*)va + off;
+}
+
+void free_page(void *ptr)
+{
+    uintptr_t va   = ((uintptr_t)ptr) & PAGE_MASK;
+    uintptr_t base = XEN_MAP_32;
+    int slot       = (va - base) >> PAGE_SHIFT;
+
+    spin_lock(&maplock);
+    maps_refcnt[slot]--;
+    spin_unlock(&maplock);
+}
+
+void *fixmap_page(struct xen_cpu *cpu, unsigned long maddr)
+{
+    static int fixmap_slot = MAPS_MAX;
+    uint32_t mfn = addr_to_frame(maddr);
+    uint32_t off = addr_offset(maddr);
+    uint32_t va;
+    int slot;
+
+    slot = fixmap_slot++;
+    printk(2, "%s: mfn %5x slot %3d\n", __FUNCTION__, mfn, slot);
+    maps_32[slot] = get_pgentry_32(mfn, EMU_PGFLAGS);
+    va = XEN_MAP_32 + slot*PAGE_SIZE;
+    return (void*)va + off;
+}
+
+/* --------------------------------------------------------------------- */
+
+pte_t *find_pte_lpt(uint32_t va)
+{
+    pte_t *lpt_base = (void*)XEN_LPT_32;
+    pte_t offset = va >> PAGE_SHIFT;
+
+    return lpt_base + offset;
+}
+
+pte_t *find_pte_map(struct xen_cpu *cpu, uint32_t va)
+{
+    pte_t *pgd;
+    pte_t *pte;
+    int g,t;
+
+    g = PGD_INDEX_32(va);
+    t = PTE_INDEX_32(va);
+    printk(5, "va %" PRIx32 " | 32 %d -> %d\n", va, g, t);
+
+    pgd  = map_page(frame_to_addr(read_cr3_mfn(cpu)));
+    printk(5, "  pgd   %3d = %08" PRIx32 "\n", g, pgd[g]);
+    if (!test_pgflag_32(pgd[g], _PAGE_PRESENT)) {
+        return NULL;
+    }
+
+    pte  = map_page(frame_to_addr(get_pgframe_32(pgd[g])));
+    printk(5, "    pte %3d = %08" PRIx32 "\n", t, pte[t]);
+    free_page(pgd);
+
+    return pte+t;
+}
+
+void pgtable_walk(struct xen_cpu *cpu, uint32_t va)
+{
+    pte_t *p;
+    p = find_pte_map(cpu, va);
+    free_page(p);
+}
+
+/* --------------------------------------------------------------------- */
+
+static inline pte_t *find_pgd(unsigned long va, uint64_t mfn, int alloc)
+{
+    pte_t *pgd = map_page(frame_to_addr(mfn));
+    pte_t *pte;
+
+    pgd += PGD_INDEX_32(va);
+    if (!test_pgflag(*pgd, _PAGE_PRESENT)) {
+        pte = get_pages(1, "pte");
+        *pgd = get_pgentry(EMU_MFN(pte), _PAGE_PRESENT);
+    }
+
+    return pgd;
+}
+
+static inline pte_t *find_pte(unsigned long va, uint64_t mfn)
+{
+    pte_t *pte = map_page(frame_to_addr(mfn));
+    return pte + PTE_INDEX_32(va);
+}
+
+static void map_one_page(struct xen_cpu *cpu, unsigned long va, uint64_t maddr,
+                         int flags)
+{
+    uint64_t mfn = addr_to_frame(maddr);
+    pte_t *pgd;
+    pte_t *pte;
+
+    pgd = find_pgd(va, read_cr3_mfn(cpu), 1);
+    pte = find_pte(va, get_pgframe(*pgd));
+    *pte = get_pgentry(mfn, flags);
+
+    free_page(pte);
+    free_page(pgd);
+}
+
+void map_region(struct xen_cpu *cpu, uint64_t va, uint32_t flags,
+                uint64_t start, uint64_t count)
+{
+    uint64_t maddr = frame_to_addr(start);
+    uint64_t maddr_end = maddr + frame_to_addr(count);
+
+    for (; maddr < maddr_end; maddr += PAGE_SIZE, va += PAGE_SIZE) {
+        map_one_page(cpu, va, maddr, flags);
+    }
+}
+
+/* --------------------------------------------------------------------- */
+
+void update_emu_mappings(uint32_t cr3_mfn)
+{
+    uint32_t *new_pgd;
+    uint32_t entry;
+    int idx;
+
+    new_pgd  = map_page(frame_to_addr(cr3_mfn));
+
+    idx = PGD_INDEX_32(XEN_M2P_32);
+    if (!test_pgflag_32(new_pgd[idx], _PAGE_PRESENT)) {
+        /* new one, must init static mappings */
+        for (; idx < PGD_COUNT_32; idx++) {
+            if (!test_pgflag_32(emu_pgd_32[idx], _PAGE_PRESENT)) {
+                continue;
+            }
+            if (idx == PGD_INDEX_32(XEN_LPT_32)) {
+                continue;
+            }
+
+            new_pgd[idx] = emu_pgd_32[idx];
+            idx++;
+        }
+    }
+
+    /* linear pgtable mapping */
+    idx = PGD_INDEX_32(XEN_LPT_32);
+    entry = get_pgentry_32(cr3_mfn, LPT_PGFLAGS);
+    if (new_pgd[idx] != entry) {
+        new_pgd[idx] = entry;
+    }
+
+    free_page(new_pgd);
+}
+
+/* --------------------------------------------------------------------- */
+
+void paging_init(struct xen_cpu *cpu)
+{
+    uintptr_t mfn_guest = emudev_get(EMUDEV_CONF_GUEST_START_PFN, 0);
+    uintptr_t init_pt_pfn = emudev_get(EMUDEV_CONF_PFN_INIT_PT, 0);
+    int idx;
+
+    idx = PGD_INDEX_32(XEN_TXT_32);
+    emu_pgd_32[idx] = get_pgentry_32(vmconf.mfn_emu, EMU_PGFLAGS | _PAGE_PSE);
+
+    idx = PGD_INDEX_32(XEN_M2P_32);
+    emu_pgd_32[idx] = get_pgentry_32(vmconf.mfn_m2p, M2P_PGFLAGS_32 | _PAGE_PSE);
+
+    idx = PGD_INDEX_32(XEN_MAP_32);
+    emu_pgd_32[idx] = get_pgentry_32(EMU_MFN(maps_32), PGT_PGFLAGS_32);
+
+    idx = PGD_INDEX_32(XEN_IPT);
+    emu_pgd_32[idx] = get_pgentry(mfn_guest + init_pt_pfn,
+                                  EMU_PGFLAGS | _PAGE_PSE);
+
+    m2p = (void*)XEN_M2P_32;
+}
-- 
1.6.0.2