[Qemu-devel] [PATCH V2 3/3] xen: Introduce VGA sync dirty bitmap support

[anthony.perard@citrix.com]

From: Anthony PERARD <anthony.perard@citrix.com>

This patch introduces phys memory client for Xen.

Only sync dirty_bitmap and set_memory are actually implemented.
migration_log will stay empty for the moment.

Xen can only log one range for bit change, so only the range in the
first call will be synced.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
---
 xen-all.c |  253 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 253 insertions(+), 0 deletions(-)

diff --git a/xen-all.c b/xen-all.c
index 939d9b7..59178ad 100644
--- a/xen-all.c
+++ b/xen-all.c
@@ -47,6 +47,14 @@
 
 #define BUFFER_IO_MAX_DELAY  100
 
+typedef struct XenPhysmap {
+    target_phys_addr_t start_addr;
+    ram_addr_t size;
+    target_phys_addr_t phys_offset;
+
+    QLIST_ENTRY(XenPhysmap) list;
+} XenPhysmap;
+
 typedef struct XenIOState {
     shared_iopage_t *shared_page;
     buffered_iopage_t *buffered_io_page;
@@ -59,6 +67,9 @@ typedef struct XenIOState {
     int send_vcpu;
 
     struct xs_handle *xenstore;
+    CPUPhysMemoryClient client;
+    QLIST_HEAD(, XenPhysmap) physmap;
+    const XenPhysmap *log_for_dirtybit;
 
     Notifier exit;
 } XenIOState;
@@ -162,6 +173,243 @@ void xen_ram_alloc(ram_addr_t ram_addr, ram_addr_t size)
     qemu_free(pfn_list);
 }
 
+static XenPhysmap *get_physmapping(XenIOState *state,
+                                   target_phys_addr_t start_addr, ram_addr_t size)
+{
+    XenPhysmap *physmap = NULL;
+
+    start_addr = TARGET_PAGE_ALIGN(start_addr);
+    /* Search for a mapping inside another mapping */
+    QLIST_FOREACH(physmap, &state->physmap, list) {
+        if (physmap->start_addr <= start_addr &&
+            start_addr + size <= (physmap->start_addr + physmap->size)) {
+            return physmap;
+        }
+    }
+    return NULL;
+}
+
+#if CONFIG_XEN_CTRL_INTERFACE_VERSION >= 340
+static int xen_add_to_physmap(XenIOState *state,
+                              target_phys_addr_t start_addr,
+                              ram_addr_t size,
+                              target_phys_addr_t phys_offset)
+{
+    unsigned long i = 0;
+    int rc = 0;
+    XenPhysmap *physmap = NULL;
+
+    if (get_physmapping(state, start_addr, size)) {
+        return 0;
+    }
+    if (size <= 0) {
+        return -1;
+    }
+
+    DPRINTF("mapping vram to %llx - %llx, from %llx\n", start_addr, start_addr + size, phys_offset);
+    for (i = 0; i < size >> TARGET_PAGE_BITS; i++) {
+        unsigned long idx = (phys_offset >> TARGET_PAGE_BITS) + i;
+
+        xen_pfn_t gpfn = (start_addr >> TARGET_PAGE_BITS) + i;
+        rc = xc_domain_add_to_physmap(xen_xc, xen_domid, XENMAPSPACE_gmfn, idx, gpfn);
+        if (rc) {
+            DPRINTF("add_to_physmap MFN %"PRI_xen_pfn" to PFN %"
+                    PRI_xen_pfn" failed: %d\n", idx, gpfn, rc);
+            return -rc;
+        }
+    }
+
+    physmap = qemu_malloc(sizeof (XenPhysmap));
+
+    physmap->start_addr = start_addr;
+    physmap->size = size;
+    physmap->phys_offset = phys_offset;
+
+    QLIST_INSERT_HEAD(&state->physmap, physmap, list);
+
+    xc_domain_pin_memory_cacheattr(xen_xc, xen_domid,
+                                   start_addr >> TARGET_PAGE_BITS,
+                                   (start_addr + size) >> TARGET_PAGE_BITS,
+                                   XEN_DOMCTL_MEM_CACHEATTR_WB);
+    return 0;
+}
+
+static int xen_remove_from_physmap(XenIOState *state,
+                                   target_phys_addr_t start_addr,
+                                   ram_addr_t size)
+{
+    unsigned long i = 0;
+    int rc = 0;
+    XenPhysmap *physmap = NULL;
+    target_phys_addr_t phys_offset = 0;
+
+    physmap = get_physmapping(state, start_addr, size);
+    if (physmap == NULL) {
+        return -1;
+    }
+
+    phys_offset = physmap->phys_offset;
+    size = physmap->size;
+
+    DPRINTF("unmapping vram to %llx - %llx, from %llx\n", phys_offset, phys_offset + size, start_addr);
+    for (i = 0; i < size >> TARGET_PAGE_BITS; i++) {
+        unsigned long idx = (start_addr >> TARGET_PAGE_BITS) + i;
+
+        xen_pfn_t gpfn = (phys_offset >> TARGET_PAGE_BITS) + i;
+        rc = xc_domain_add_to_physmap(xen_xc, xen_domid, XENMAPSPACE_gmfn, idx, gpfn);
+        if (rc) {
+            fprintf(stderr, "add_to_physmap MFN %"PRI_xen_pfn" to PFN %"
+                    PRI_xen_pfn" failed: %d\n", idx, gpfn, rc);
+            return -rc;
+        }
+    }
+
+    QLIST_REMOVE(physmap, list);
+    if (state->log_for_dirtybit == physmap) {
+        state->log_for_dirtybit = NULL;
+    }
+    free(physmap);
+
+    return 0;
+}
+
+#else
+static int xen_add_to_physmap(XenIOState *state,
+                              target_phys_addr_t start_addr,
+                              ram_addr_t size,
+                              target_phys_addr_t phys_offset)
+{
+    return -ENOSYS;
+}
+
+static int xen_remove_from_physmap(XenIOState *state,
+                                   target_phys_addr_t start_addr,
+                                   ram_addr_t size)
+{
+    return -ENOSYS;
+}
+#endif
+
+static void xen_client_set_memory(struct CPUPhysMemoryClient *client,
+                                  target_phys_addr_t start_addr,
+                                  ram_addr_t size,
+                                  ram_addr_t phys_offset)
+{
+    XenIOState *state = container_of(client, XenIOState, client);
+    ram_addr_t flags = phys_offset & ~TARGET_PAGE_MASK;
+    hvmmem_type_t mem_type;
+
+    start_addr = TARGET_PAGE_ALIGN(start_addr);
+    size = TARGET_PAGE_ALIGN(size);
+    phys_offset = TARGET_PAGE_ALIGN(phys_offset);
+
+    /* Xen does not need to know about this memory */
+    if (flags > IO_MEM_UNASSIGNED) {
+        return;
+    }
+
+    switch (flags) {
+    case IO_MEM_RAM:
+        xen_add_to_physmap(state, start_addr, size, phys_offset);
+        break;
+    case IO_MEM_ROM:
+        mem_type = HVMMEM_ram_ro;
+        if (xc_hvm_set_mem_type(xen_xc, xen_domid, mem_type,
+                                start_addr >> TARGET_PAGE_BITS,
+                                size >> TARGET_PAGE_BITS)) {
+            DPRINTF("xc_hvm_set_mem_type error, addr: "TARGET_FMT_plx"\n",
+                    start_addr);
+        }
+        break;
+    case IO_MEM_UNASSIGNED:
+        if (xen_remove_from_physmap(state, start_addr, size) < 0) {
+            DPRINTF("physmapping does not exist at "TARGET_FMT_plx"\n", start_addr);
+        }
+        break;
+    }
+}
+
+static int xen_sync_dirty_bitmap(XenIOState *state,
+                                 target_phys_addr_t start_addr,
+                                 ram_addr_t size)
+{
+    target_phys_addr_t npages = size >> TARGET_PAGE_BITS;
+    target_phys_addr_t vram_offset = 0;
+    const int width = sizeof(unsigned long) * 8;
+    unsigned long bitmap[(npages + width - 1) / width];
+    int rc, i, j;
+    const XenPhysmap *physmap = NULL;
+
+    physmap = get_physmapping(state, start_addr, size);
+    if (physmap == NULL) {
+        /* not handled */
+        return -1;
+    }
+
+    if (state->log_for_dirtybit == NULL) {
+        state->log_for_dirtybit = physmap;
+    } else if (state->log_for_dirtybit != physmap) {
+        return -1;
+    }
+    vram_offset = physmap->phys_offset;
+
+    rc = xc_hvm_track_dirty_vram(xen_xc, xen_domid,
+                                 start_addr >> TARGET_PAGE_BITS, npages,
+                                 bitmap);
+    if (rc) {
+        return rc;
+    }
+
+    for (i = 0; i < ARRAY_SIZE(bitmap); i++) {
+        unsigned long map = bitmap[i];
+        while (map != 0) {
+            j = ffsl(map) - 1;
+            map &= ~(1ul << j);
+            cpu_physical_memory_set_dirty(vram_offset + (i * width + j) * TARGET_PAGE_SIZE);
+        };
+    }
+
+    return 0;
+}
+
+static int xen_log_start(CPUPhysMemoryClient *client, target_phys_addr_t phys_addr, ram_addr_t size)
+{
+    XenIOState *state = container_of(client, XenIOState, client);
+
+    return xen_sync_dirty_bitmap(state, phys_addr, size);
+}
+
+static int xen_log_stop(CPUPhysMemoryClient *client, target_phys_addr_t phys_addr, ram_addr_t size)
+{
+    XenIOState *state = container_of(client, XenIOState, client);
+
+    state->log_for_dirtybit = NULL;
+    /* Disable dirty bit tracking */
+    return xc_hvm_track_dirty_vram(xen_xc, xen_domid, 0, 0, NULL);
+}
+
+static int xen_client_sync_dirty_bitmap(struct CPUPhysMemoryClient *client,
+                                        target_phys_addr_t start_addr,
+                                        target_phys_addr_t end_addr)
+{
+    XenIOState *state = container_of(client, XenIOState, client);
+
+    return xen_sync_dirty_bitmap(state, start_addr, end_addr - start_addr);
+}
+
+static int xen_client_migration_log(struct CPUPhysMemoryClient *client,
+                                    int enable)
+{
+    return 0;
+}
+
+static CPUPhysMemoryClient xen_cpu_phys_memory_client = {
+    .set_memory = xen_client_set_memory,
+    .sync_dirty_bitmap = xen_client_sync_dirty_bitmap,
+    .migration_log = xen_client_migration_log,
+    .log_start = xen_log_start,
+    .log_stop = xen_log_stop,
+};
 
 /* VCPU Operations, MMIO, IO ring ... */
 
@@ -553,6 +801,11 @@ int xen_init(int smp_cpus)
 
     qemu_add_vm_change_state_handler(xen_vm_change_state_handler, state);
 
+    state->client = xen_cpu_phys_memory_client;
+    QLIST_INIT(&state->physmap);
+    cpu_register_phys_memory_client(&state->client);
+    state->log_for_dirtybit = NULL;
+
     return 0;
 }
 
-- 
1.7.1