[PATCH v1 2/2] ioreq-server: Support scatter page forwarding

[Wei Ye <wei.ye@intel.com>]

Extend the interface to support add/remove scatter page list to be
forwarded by a dedicated ioreq-server instance. Check and select
a right ioreq-server instance for forwarding the wirte operation
for a write protected page.

Signed-off-by: Wei Ye <wei.ye@intel.com>
---
 tools/libxc/xc_domain.c          |   32 ++++++
 tools/libxc/xenctrl.h            |   18 ++++
 xen/arch/x86/hvm/hvm.c           |  206 +++++++++++++++++++++++++++++++++++++-
 xen/include/asm-x86/hvm/domain.h |   14 +++
 xen/include/public/hvm/hvm_op.h  |   12 +++
 5 files changed, 281 insertions(+), 1 deletion(-)

diff --git a/tools/libxc/xc_domain.c b/tools/libxc/xc_domain.c
index 37ed141..9afc843 100644
--- a/tools/libxc/xc_domain.c
+++ b/tools/libxc/xc_domain.c
@@ -1485,6 +1485,38 @@ int xc_hvm_unmap_pcidev_from_ioreq_server(xc_interface *xch, domid_t domid,
     return rc;
 }
 
+int xc_hvm_map_pages_to_ioreq_server(xc_interface *xch, domid_t domid,
+                                     ioservid_t id, uint16_t set,
+                                     uint16_t nr_pages, unsigned long *gpfn)
+{
+    DECLARE_HYPERCALL;
+    DECLARE_HYPERCALL_BUFFER(xen_hvm_map_pages_to_ioreq_server_t, arg);
+    int pg, rc = -1;
+
+    if ( arg == NULL )
+        return -1;
+    
+    if (nr_pages > MAX_MAP_BATCH_PAGES)
+        goto out;
+
+    hypercall.op     = __HYPERVISOR_hvm_op;
+    hypercall.arg[0] = HVMOP_map_pages_to_ioreq_server;
+    hypercall.arg[1] = HYPERCALL_BUFFER_AS_ARG(arg);
+
+    arg->domid = domid;
+    arg->id = id;
+    arg->set = set;
+    arg->nr_pages = nr_pages;
+    for ( pg = 0; pg < nr_pages; pg++ )
+        arg->page_list[pg] = gpfn[pg];
+
+    rc = do_xen_hypercall(xch, &hypercall);
+
+out:
+    xc_hypercall_buffer_free(xch, arg);
+    return rc;
+}
+
 int xc_hvm_destroy_ioreq_server(xc_interface *xch,
                                 domid_t domid,
                                 ioservid_t id)
diff --git a/tools/libxc/xenctrl.h b/tools/libxc/xenctrl.h
index b55d857..e5e37b0 100644
--- a/tools/libxc/xenctrl.h
+++ b/tools/libxc/xenctrl.h
@@ -1943,6 +1943,24 @@ int xc_hvm_unmap_pcidev_from_ioreq_server(xc_interface *xch,
                                           uint8_t function);
 
 /**
+ * This function registers/deregisters a set of pages to be write protected.
+ *
+ * @parm xch a handle to an open hypervisor interface.
+ * @parm domid the domain id to be serviced
+ * @parm id the IOREQ Server id.
+ * @parm set whether registers or deregisters: 1 for register, 0 for deregister
+ * @parm nr_pages the number of pages
+ * @parm pgfn the guest page frame number list
+ * @return 0 on success, -1 on failure.
+ */
+int xc_hvm_map_pages_to_ioreq_server(xc_interface *xch,
+                                          domid_t domid,
+                                          ioservid_t id,
+                                          uint16_t set,
+                                          uint16_t nr_pages,
+                                          unsigned long *gpfn);
+
+/**
  * This function destroys an IOREQ Server.
  *
  * @parm xch a handle to an open hypervisor interface.
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 0f20b62..44e0640 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -744,6 +744,98 @@ static void hvm_ioreq_server_remove_all_vcpus(struct hvm_ioreq_server *s)
     spin_unlock(&s->lock);
 }
 
+static struct pglist_hash_table *hvm_ioreq_server_lookup_pglist_hash_table(
+                          struct pglist_hash_table *pglist_ht, unsigned long gpfn)
+{
+    int index = pglist_hash(gpfn);
+    struct pglist_hash_table *entry;
+
+    for ( entry = &pglist_ht[index]; entry != NULL; entry = entry->next )
+        if ( entry->gpfn != PGLIST_INVALID_GPFN && entry->gpfn == gpfn )
+            break;
+
+    return entry;
+}
+
+static void hvm_ioreq_server_free_hash_chain(struct pglist_hash_table *chain)
+{
+    struct pglist_hash_table *p = chain;
+    struct pglist_hash_table *n;
+
+    while (p)
+    {
+        n = p->next;
+        xfree(p);
+        p = n;
+    }
+}
+
+static void hvm_ioreq_server_free_pglist_hash(struct pglist_hash_table *pglist_ht)
+{
+    unsigned int i;
+
+    for ( i = 0; i < PGLIST_HASH_SIZE; i++ )
+        if ( pglist_ht[i].next != NULL )
+            hvm_ioreq_server_free_hash_chain(pglist_ht[i].next);
+}
+
+static int hvm_ioreq_server_pglist_hash_add(struct pglist_hash_table *pglist_ht,
+                                            unsigned long gpfn)
+{
+    int index = pglist_hash(gpfn);
+    struct pglist_hash_table *ne;
+
+    if ( hvm_ioreq_server_lookup_pglist_hash_table(pglist_ht, gpfn) != NULL )
+        return -EINVAL;
+
+    if ( pglist_ht[index].gpfn == PGLIST_INVALID_GPFN )
+        pglist_ht[index].gpfn = gpfn;
+    else
+    {
+        ne = xmalloc_bytes(sizeof(pglist_ht[0]));
+        if ( !ne )
+            return -ENOMEM;
+        ne->next = pglist_ht[index].next;
+        ne->gpfn = gpfn;
+        pglist_ht[index].next = ne;
+    }
+
+    return 0;
+}
+
+static int hvm_ioreq_server_pglist_hash_rem(struct pglist_hash_table *pglist_ht,
+                                            unsigned long gpfn)
+{
+    int index = pglist_hash(gpfn);
+    struct pglist_hash_table *next, *prev;
+
+    if ( pglist_ht[index].gpfn == gpfn )
+        pglist_ht[index].gpfn = PGLIST_INVALID_GPFN;
+    else
+    {
+        prev = &pglist_ht[index];
+        while ( 1 )
+        {
+            next = prev->next;
+            if ( !next )
+            {
+                printk("hvm_ioreq_server_pglist_hash_rem hash_table %p remove"
+                       " %lx not found\n", pglist_ht, gpfn);
+                return -EINVAL;
+            }
+            if ( next->gpfn == gpfn )
+            {
+                prev->next = next->next;
+                xfree(next);
+                break;
+            }
+            prev = next;
+         }
+    }
+
+    return 0;
+}
+
 static int hvm_ioreq_server_map_pages(struct hvm_ioreq_server *s,
                                       bool_t is_default, bool_t handle_bufioreq)
 {
@@ -948,7 +1040,14 @@ static int hvm_ioreq_server_init(struct hvm_ioreq_server *s, struct domain *d,
     spin_lock_init(&s->lock);
     INIT_LIST_HEAD(&s->ioreq_vcpu_list);
     spin_lock_init(&s->bufioreq_lock);
+    spin_lock_init(&s->pglist_hash_lock);
 
+    rc = -ENOMEM;
+    s->pglist_hash_base = xmalloc_bytes(PGLIST_HASH_ENTRY_SIZE * PGLIST_HASH_SIZE);
+    if ( s->pglist_hash_base == NULL )
+        goto fail1;
+    memset(s->pglist_hash_base, 0, PGLIST_HASH_ENTRY_SIZE * PGLIST_HASH_SIZE);
+ 
     rc = hvm_ioreq_server_alloc_rangesets(s, is_default);
     if ( rc )
         goto fail1;
@@ -1087,6 +1186,9 @@ static int hvm_destroy_ioreq_server(struct domain *d, ioservid_t id)
         
         hvm_ioreq_server_deinit(s, 0);
 
+        hvm_ioreq_server_free_pglist_hash(s->pglist_hash_base);
+        xfree(s->pglist_hash_base);
+
         domain_unpause(d);
 
         xfree(s);
@@ -1279,6 +1381,63 @@ static int hvm_set_ioreq_server_state(struct domain *d, ioservid_t id,
     return rc;
 }
 
+static int hvm_map_pages_to_ioreq_server(struct domain *d, ioservid_t id,
+                                        uint16_t set, uint16_t nr_pages,
+                                        unsigned long *gpfn)
+{
+    struct hvm_ioreq_server *s;
+    int rc;
+    unsigned int i;
+    p2m_type_t ot, nt;
+
+    if ( set )
+    {
+        ot = p2m_ram_rw;
+        nt = p2m_ram_wp;
+    }
+    else
+    {
+        ot = p2m_ram_wp;
+        nt = p2m_ram_rw;
+    }
+
+    spin_lock(&d->arch.hvm_domain.ioreq_server.lock);
+
+    rc = -ENOENT;
+    list_for_each_entry ( s,
+                          &d->arch.hvm_domain.ioreq_server.list,
+                          list_entry )
+    {
+        if ( s == d->arch.hvm_domain.default_ioreq_server )
+            continue;
+
+        if ( s->id == id )
+        {
+            spin_lock(&s->pglist_hash_lock);
+
+            for ( i = 0; i < nr_pages; i++ )
+            {
+                p2m_change_type_one(d, gpfn[i], ot, nt);
+                if ( set )
+                    rc = hvm_ioreq_server_pglist_hash_add(s->pglist_hash_base, gpfn[i]);
+                else
+                    rc = hvm_ioreq_server_pglist_hash_rem(s->pglist_hash_base, gpfn[i]);
+
+                 if ( rc != 0 )
+                     break;
+            }
+
+            spin_unlock(&s->pglist_hash_lock);
+            flush_tlb_mask(d->domain_dirty_cpumask);
+            break;
+        }
+    }
+
+    spin_unlock(&d->arch.hvm_domain.ioreq_server.lock);
+
+    return rc;
+}
+
 static int hvm_all_ioreq_servers_add_vcpu(struct domain *d, struct vcpu *v)
 {
     struct hvm_ioreq_server *s;
@@ -2294,6 +2453,8 @@ static struct hvm_ioreq_server *hvm_select_ioreq_server(struct domain *d,
     uint32_t cf8;
     uint8_t type;
     uint64_t addr;
+    unsigned long gpfn;
+    struct pglist_hash_table *he;
 
     if ( list_empty(&d->arch.hvm_domain.ioreq_server.list) )
         return NULL;
@@ -2361,6 +2522,15 @@ static struct hvm_ioreq_server *hvm_select_ioreq_server(struct domain *d,
             if ( rangeset_contains_range(r, addr, end) )
                 return s;
 
+            gpfn = addr >> PAGE_SHIFT;
+            spin_lock(&s->pglist_hash_lock);
+            he = hvm_ioreq_server_lookup_pglist_hash_table(s->pglist_hash_base, gpfn);
+            spin_unlock(&s->pglist_hash_lock);
+
+            if ( he ) {
+                return s;
+            }
+
             break;
         case IOREQ_TYPE_PCI_CONFIG:
             if ( rangeset_contains_singleton(r, addr >> 32) )
@@ -5314,6 +5484,35 @@ static int hvmop_set_ioreq_server_state(
     return rc;
 }
 
+static int hvmop_map_pages_to_ioreq_server(
+    XEN_GUEST_HANDLE_PARAM(xen_hvm_map_pages_to_ioreq_server_t) uop)
+{
+    xen_hvm_map_pages_to_ioreq_server_t op;
+    struct domain *d;
+    int rc;
+
+    if ( copy_from_guest(&op, uop, 1) )
+        return -EFAULT;
+
+    rc = rcu_lock_remote_domain_by_id(op.domid, &d);
+    if ( rc != 0 )
+        return rc;
+
+    rc = -EINVAL;
+    if ( !is_hvm_domain(d) )
+        goto out;
+
+    rc = xsm_hvm_ioreq_server(XSM_DM_PRIV, d, HVMOP_map_pages_to_ioreq_server);
+    if ( rc != 0 )
+        goto out;
+
+    rc = hvm_map_pages_to_ioreq_server(d, op.id, op.set, op.nr_pages, op.page_list);
+
+out:
+    rcu_unlock_domain(d);
+    return rc;
+}
+
 static int hvmop_destroy_ioreq_server(
     XEN_GUEST_HANDLE_PARAM(xen_hvm_destroy_ioreq_server_t) uop)
 {
@@ -5378,7 +5577,12 @@ long do_hvm_op(unsigned long op, XEN_GUEST_HANDLE_PARAM(void) arg)
         rc = hvmop_set_ioreq_server_state(
             guest_handle_cast(arg, xen_hvm_set_ioreq_server_state_t));
         break;
-    
+
+    case HVMOP_map_pages_to_ioreq_server:
+        rc = hvmop_map_pages_to_ioreq_server(
+            guest_handle_cast(arg, xen_hvm_map_pages_to_ioreq_server_t));
+        break;
+ 
     case HVMOP_destroy_ioreq_server:
         rc = hvmop_destroy_ioreq_server(
             guest_handle_cast(arg, xen_hvm_destroy_ioreq_server_t));
diff --git a/xen/include/asm-x86/hvm/domain.h b/xen/include/asm-x86/hvm/domain.h
index 291a2e0..47172ca 100644
--- a/xen/include/asm-x86/hvm/domain.h
+++ b/xen/include/asm-x86/hvm/domain.h
@@ -48,6 +48,16 @@ struct hvm_ioreq_vcpu {
     evtchn_port_t    ioreq_evtchn;
 };
 
+struct pglist_hash_table {
+    struct pglist_hash_table *next;
+    unsigned long gpfn;
+};
+#define PGLIST_HASH_SIZE_SHIFT    8
+#define PGLIST_HASH_SIZE    (1 << PGLIST_HASH_SIZE_SHIFT)
+#define pglist_hash(x)      ((x) % PGLIST_HASH_SIZE)
+#define PGLIST_INVALID_GPFN       0
+#define PGLIST_HASH_ENTRY_SIZE    sizeof(struct pglist_hash_table)
+
 #define NR_IO_RANGE_TYPES (HVMOP_IO_RANGE_PCI + 1)
 #define MAX_NR_IO_RANGES  256
 
@@ -70,6 +80,10 @@ struct hvm_ioreq_server {
     evtchn_port_t          bufioreq_evtchn;
     struct rangeset        *range[NR_IO_RANGE_TYPES];
     bool_t                 enabled;
+
+    /* scatter page list need write protection */
+    struct pglist_hash_table   *pglist_hash_base;
+    spinlock_t             pglist_hash_lock;
 };
 
 struct hvm_domain {
diff --git a/xen/include/public/hvm/hvm_op.h b/xen/include/public/hvm/hvm_op.h
index eeb0a60..53a966b 100644
--- a/xen/include/public/hvm/hvm_op.h
+++ b/xen/include/public/hvm/hvm_op.h
@@ -367,6 +367,18 @@ struct xen_hvm_set_ioreq_server_state {
 typedef struct xen_hvm_set_ioreq_server_state xen_hvm_set_ioreq_server_state_t;
 DEFINE_XEN_GUEST_HANDLE(xen_hvm_set_ioreq_server_state_t);
 
+#define HVMOP_map_pages_to_ioreq_server 23
+#define MAX_MAP_BATCH_PAGES             128
+struct xen_hvm_map_pages_to_ioreq_server {
+    domid_t domid;   /* IN - domain to be serviced */
+    ioservid_t id;   /* IN - server id */
+    uint16_t set;    /* IN - 1: map pages, 0: unmap pages */
+    uint16_t nr_pages;  /* IN - page number */
+    unsigned long page_list[MAX_MAP_BATCH_PAGES]; /* IN - gpfn list */
+};
+typedef struct xen_hvm_map_pages_to_ioreq_server xen_hvm_map_pages_to_ioreq_server_t;
+DEFINE_XEN_GUEST_HANDLE(xen_hvm_map_pages_to_ioreq_server_t);
+
 #endif /* defined(__XEN__) || defined(__XEN_TOOLS__) */
 
 #endif /* __XEN_PUBLIC_HVM_HVM_OP_H__ */
-- 
1.7.9.5