[PATCH v3 0/2] Refactor ioreq server for better performance.

[PATCH v3 0/2] Refactor ioreq server for better performance.

[Yu Zhang]

XenGT leverages ioreq server to track and forward the accesses to
GPU I/O resources, e.g. the PPGTT(per-process graphic translation
tables). Currently, ioreq server uses rangeset to track the BDF/
PIO/MMIO ranges to be emulated. To select an ioreq server, the 
rangeset is searched to see if the I/O range is recorded. However,
traversing the link list inside rangeset could be time consuming
when number of ranges is too high. On HSW platform, number of PPGTTs
for each vGPU could be several hundred. On BDW, this value could
be several thousand.  This patch series refactored rangeset to base
it on red-back tree, so that the searching would be more efficient. 

Besides, this patchset also splits the tracking of MMIO and guest
ram ranges into different rangesets. And to accommodate more ranges,
limitation of the number of ranges in an ioreq server, MAX_NR_IO_RANGES
is changed - future patches might be provided to tune this with other
approaches.


Changes in v3: 
1> Use a seperate rangeset for guest ram pages in ioreq server;
2> Refactor rangeset, instead of introduce a new data structure.

Changes in v2: 
1> Split the original patch into 2;
2> Take Paul Durrant's comments:
  a> Add a name member in the struct rb_rangeset, and use the 'q' 
debug key to dump the ranges in ioreq server;
  b> Keep original routine names for hvm ioreq server;
  c> Commit message changes - mention that a future patch to change
the maximum ranges inside ioreq server.

Yu Zhang (2):
  Differentiate IO/mem resources tracked by ioreq server
  Refactor rangeset structure for better performance.

 tools/libxc/include/xenctrl.h    | 39 +++++++++++++++++--
 tools/libxc/xc_domain.c          | 59 ++++++++++++++++++++++++++++-
 xen/arch/x86/hvm/hvm.c           | 33 ++++++++++++++--
 xen/common/rangeset.c            | 82 +++++++++++++++++++++++++++++-----------
 xen/include/asm-x86/hvm/domain.h |  4 +-
 xen/include/public/hvm/hvm_op.h  |  3 +-
 xen/include/public/hvm/ioreq.h   |  1 +
 7 files changed, 186 insertions(+), 35 deletions(-)

-- 
1.9.1

[PATCH v3 1/2] Differentiate IO/mem resources tracked by ioreq server

[Yu Zhang]

Currently in ioreq server, guest write-protected ram pages are
tracked in the same rangeset with device mmio resources. Yet
unlike device mmio, which can be in big chunks, the guest write-
protected pages may be discrete ranges with 4K bytes each.

This patch uses a seperate rangeset for the guest ram pages.
And a new ioreq type, IOREQ_TYPE_MEM, is defined.

Note: Previously, a new hypercall or subop was suggested to map
write-protected pages into ioreq server. However, it turned out
handler of this new hypercall would be almost the same with the
existing pair - HVMOP_[un]map_io_range_to_ioreq_server, and there's
already a type parameter in this hypercall. So no new hypercall
defined, only a new type is introduced.

Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
---
 tools/libxc/include/xenctrl.h    | 39 +++++++++++++++++++++++---
 tools/libxc/xc_domain.c          | 59 ++++++++++++++++++++++++++++++++++++++--
 xen/arch/x86/hvm/hvm.c           | 33 +++++++++++++++++++---
 xen/include/asm-x86/hvm/domain.h |  4 +--
 xen/include/public/hvm/hvm_op.h  |  3 +-
 xen/include/public/hvm/ioreq.h   |  1 +
 6 files changed, 126 insertions(+), 13 deletions(-)

diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
index de3c0ad..3e8c203 100644
--- a/tools/libxc/include/xenctrl.h
+++ b/tools/libxc/include/xenctrl.h
@@ -1976,12 +1976,12 @@ int xc_hvm_set_ioreq_server_state(xc_interface *xch,
                                   int enabled);
 
 /**
- * This function registers a range of memory or I/O ports for emulation.
+ * This function registers a range of mmio or I/O ports for emulation.
  *
  * @parm xch a handle to an open hypervisor interface.
  * @parm domid the domain id to be serviced
  * @parm id the IOREQ Server id.
- * @parm is_mmio is this a range of ports or memory
+ * @parm is_mmio is this a range of ports or mmio
  * @parm start start of range
  * @parm end end of range (inclusive).
  * @return 0 on success, -1 on failure.
@@ -1994,12 +1994,12 @@ int xc_hvm_map_io_range_to_ioreq_server(xc_interface *xch,
                                         uint64_t end);
 
 /**
- * This function deregisters a range of memory or I/O ports for emulation.
+ * This function deregisters a range of mmio or I/O ports for emulation.
  *
  * @parm xch a handle to an open hypervisor interface.
  * @parm domid the domain id to be serviced
  * @parm id the IOREQ Server id.
- * @parm is_mmio is this a range of ports or memory
+ * @parm is_mmio is this a range of ports or mmio
  * @parm start start of range
  * @parm end end of range (inclusive).
  * @return 0 on success, -1 on failure.
@@ -2010,6 +2010,37 @@ int xc_hvm_unmap_io_range_from_ioreq_server(xc_interface *xch,
                                             int is_mmio,
                                             uint64_t start,
                                             uint64_t end);
+/**
+ * This function registers a range of memory for emulation.
+ *
+ * @parm xch a handle to an open hypervisor interface.
+ * @parm domid the domain id to be serviced
+ * @parm id the IOREQ Server id.
+ * @parm start start of range
+ * @parm end end of range (inclusive).
+ * @return 0 on success, -1 on failure.
+ */
+int xc_hvm_map_mem_range_to_ioreq_server(xc_interface *xch,
+                                        domid_t domid,
+                                        ioservid_t id,
+                                        uint64_t start,
+                                        uint64_t end);
+
+/**
+ * This function deregisters a range of memory for emulation.
+ *
+ * @parm xch a handle to an open hypervisor interface.
+ * @parm domid the domain id to be serviced
+ * @parm id the IOREQ Server id.
+ * @parm start start of range
+ * @parm end end of range (inclusive).
+ * @return 0 on success, -1 on failure.
+ */
+int xc_hvm_unmap_mem_range_from_ioreq_server(xc_interface *xch,
+                                            domid_t domid,
+                                            ioservid_t id,
+                                            uint64_t start,
+                                            uint64_t end);
 
 /**
  * This function registers a PCI device for config space emulation.
diff --git a/tools/libxc/xc_domain.c b/tools/libxc/xc_domain.c
index 2ee26fb..7b36c99 100644
--- a/tools/libxc/xc_domain.c
+++ b/tools/libxc/xc_domain.c
@@ -1514,7 +1514,7 @@ int xc_hvm_map_io_range_to_ioreq_server(xc_interface *xch, domid_t domid,
 
     arg->domid = domid;
     arg->id = id;
-    arg->type = is_mmio ? HVMOP_IO_RANGE_MEMORY : HVMOP_IO_RANGE_PORT;
+    arg->type = is_mmio ? HVMOP_IO_RANGE_MMIO : HVMOP_IO_RANGE_PORT;
     arg->start = start;
     arg->end = end;
 
@@ -1542,7 +1542,7 @@ int xc_hvm_unmap_io_range_from_ioreq_server(xc_interface *xch, domid_t domid,
 
     arg->domid = domid;
     arg->id = id;
-    arg->type = is_mmio ? HVMOP_IO_RANGE_MEMORY : HVMOP_IO_RANGE_PORT;
+    arg->type = is_mmio ? HVMOP_IO_RANGE_MMIO : HVMOP_IO_RANGE_PORT;
     arg->start = start;
     arg->end = end;
 
@@ -1552,6 +1552,61 @@ int xc_hvm_unmap_io_range_from_ioreq_server(xc_interface *xch, domid_t domid,
     return rc;
 }
 
+int xc_hvm_map_mem_range_to_ioreq_server(xc_interface *xch, domid_t domid,
+                                        ioservid_t id, uint64_t start, uint64_t end)
+{
+    DECLARE_HYPERCALL;
+    DECLARE_HYPERCALL_BUFFER(xen_hvm_io_range_t, arg);
+    int rc;
+
+    arg = xc_hypercall_buffer_alloc(xch, arg, sizeof(*arg));
+    if ( arg == NULL )
+        return -1;
+
+    hypercall.op     = __HYPERVISOR_hvm_op;
+    hypercall.arg[0] = HVMOP_map_io_range_to_ioreq_server;
+    hypercall.arg[1] = HYPERCALL_BUFFER_AS_ARG(arg);
+
+    arg->domid = domid;
+    arg->id = id;
+    arg->type = HVMOP_IO_RANGE_MEMORY;
+    arg->start = start;
+    arg->end = end;
+
+    rc = do_xen_hypercall(xch, &hypercall);
+
+    xc_hypercall_buffer_free(xch, arg);
+    return rc;
+}
+
+int xc_hvm_unmap_mem_range_from_ioreq_server(xc_interface *xch, domid_t domid,
+                                            ioservid_t id, uint64_t start, uint64_t end)
+{
+    DECLARE_HYPERCALL;
+    DECLARE_HYPERCALL_BUFFER(xen_hvm_io_range_t, arg);
+    int rc;
+
+    arg = xc_hypercall_buffer_alloc(xch, arg, sizeof(*arg));
+    if ( arg == NULL )
+        return -1;
+
+    hypercall.op     = __HYPERVISOR_hvm_op;
+    hypercall.arg[0] = HVMOP_unmap_io_range_from_ioreq_server;
+    hypercall.arg[1] = HYPERCALL_BUFFER_AS_ARG(arg);
+
+    arg->domid = domid;
+    arg->id = id;
+    arg->type = HVMOP_IO_RANGE_MEMORY;
+    arg->start = start;
+    arg->end = end;
+
+    rc = do_xen_hypercall(xch, &hypercall);
+
+    xc_hypercall_buffer_free(xch, arg);
+    return rc;
+
+}
+
 int xc_hvm_map_pcidev_to_ioreq_server(xc_interface *xch, domid_t domid,
                                       ioservid_t id, uint16_t segment,
                                       uint8_t bus, uint8_t device,
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index c957610..d76e3ce 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -938,8 +938,9 @@ static int hvm_ioreq_server_alloc_rangesets(struct hvm_ioreq_server *s,
 
         rc = asprintf(&name, "ioreq_server %d %s", s->id,
                       (i == HVMOP_IO_RANGE_PORT) ? "port" :
-                      (i == HVMOP_IO_RANGE_MEMORY) ? "memory" :
+                      (i == HVMOP_IO_RANGE_MMIO) ? "mmio" :
                       (i == HVMOP_IO_RANGE_PCI) ? "pci" :
+                      (i == HVMOP_IO_RANGE_MEMORY) ? "memory" :
                       "");
         if ( rc )
             goto fail;
@@ -1256,8 +1257,9 @@ static int hvm_map_io_range_to_ioreq_server(struct domain *d, ioservid_t id,
             switch ( type )
             {
             case HVMOP_IO_RANGE_PORT:
-            case HVMOP_IO_RANGE_MEMORY:
+            case HVMOP_IO_RANGE_MMIO:
             case HVMOP_IO_RANGE_PCI:
+            case HVMOP_IO_RANGE_MEMORY:
                 r = s->range[type];
                 break;
 
@@ -1307,8 +1309,9 @@ static int hvm_unmap_io_range_from_ioreq_server(struct domain *d, ioservid_t id,
             switch ( type )
             {
             case HVMOP_IO_RANGE_PORT:
-            case HVMOP_IO_RANGE_MEMORY:
+            case HVMOP_IO_RANGE_MMIO:
             case HVMOP_IO_RANGE_PCI:
+            case HVMOP_IO_RANGE_MEMORY:
                 r = s->range[type];
                 break;
 
@@ -2523,6 +2526,8 @@ struct hvm_ioreq_server *hvm_select_ioreq_server(struct domain *d,
     uint32_t cf8;
     uint8_t type;
     uint64_t addr;
+    p2m_type_t p2mt;
+    struct page_info *ram_page;
 
     if ( list_empty(&d->arch.hvm_domain.ioreq_server.list) )
         return NULL;
@@ -2565,6 +2570,18 @@ struct hvm_ioreq_server *hvm_select_ioreq_server(struct domain *d,
     {
         type = p->type;
         addr = p->addr;
+
+        if ( p->type == IOREQ_TYPE_COPY )
+        {
+            /* Check for paged out page */
+            ram_page = get_page_from_gfn(d, p->addr >> PAGE_SHIFT,
+                                         &p2mt, P2M_UNSHARE);
+            if ( p2mt == p2m_mmio_write_dm )
+                type = IOREQ_TYPE_MEM;
+
+            if ( ram_page )
+                put_page(ram_page);
+        }
     }
 
     list_for_each_entry ( s,
@@ -2580,8 +2597,9 @@ struct hvm_ioreq_server *hvm_select_ioreq_server(struct domain *d,
             continue;
 
         BUILD_BUG_ON(IOREQ_TYPE_PIO != HVMOP_IO_RANGE_PORT);
-        BUILD_BUG_ON(IOREQ_TYPE_COPY != HVMOP_IO_RANGE_MEMORY);
+        BUILD_BUG_ON(IOREQ_TYPE_COPY != HVMOP_IO_RANGE_MMIO);
         BUILD_BUG_ON(IOREQ_TYPE_PCI_CONFIG != HVMOP_IO_RANGE_PCI);
+        BUILD_BUG_ON(IOREQ_TYPE_MEM != HVMOP_IO_RANGE_MEMORY);
         r = s->range[type];
 
         switch ( type )
@@ -2609,6 +2627,13 @@ struct hvm_ioreq_server *hvm_select_ioreq_server(struct domain *d,
             }
 
             break;
+
+        case IOREQ_TYPE_MEM:
+            end = addr + (p->size * p->count) - 1;
+            if ( rangeset_contains_range(r, addr, end) )
+                return s;
+
+            break;
         }
     }
 
diff --git a/xen/include/asm-x86/hvm/domain.h b/xen/include/asm-x86/hvm/domain.h
index 992d5d1..8b84aea 100644
--- a/xen/include/asm-x86/hvm/domain.h
+++ b/xen/include/asm-x86/hvm/domain.h
@@ -48,8 +48,8 @@ struct hvm_ioreq_vcpu {
     bool_t           pending;
 };
 
-#define NR_IO_RANGE_TYPES (HVMOP_IO_RANGE_PCI + 1)
-#define MAX_NR_IO_RANGES  256
+#define NR_IO_RANGE_TYPES (HVMOP_IO_RANGE_MEMORY + 1)
+#define MAX_NR_IO_RANGES  8192
 
 struct hvm_ioreq_server {
     struct list_head       list_entry;
diff --git a/xen/include/public/hvm/hvm_op.h b/xen/include/public/hvm/hvm_op.h
index 014546a..9106cb9 100644
--- a/xen/include/public/hvm/hvm_op.h
+++ b/xen/include/public/hvm/hvm_op.h
@@ -329,8 +329,9 @@ struct xen_hvm_io_range {
     ioservid_t id;               /* IN - server id */
     uint32_t type;               /* IN - type of range */
 # define HVMOP_IO_RANGE_PORT   0 /* I/O port range */
-# define HVMOP_IO_RANGE_MEMORY 1 /* MMIO range */
+# define HVMOP_IO_RANGE_MMIO   1 /* MMIO range */
 # define HVMOP_IO_RANGE_PCI    2 /* PCI segment/bus/dev/func range */
+# define HVMOP_IO_RANGE_MEMORY 3 /* MEMORY range */
     uint64_aligned_t start, end; /* IN - inclusive start and end of range */
 };
 typedef struct xen_hvm_io_range xen_hvm_io_range_t;
diff --git a/xen/include/public/hvm/ioreq.h b/xen/include/public/hvm/ioreq.h
index 2e5809b..1d51e60 100644
--- a/xen/include/public/hvm/ioreq.h
+++ b/xen/include/public/hvm/ioreq.h
@@ -35,6 +35,7 @@
 #define IOREQ_TYPE_PIO          0 /* pio */
 #define IOREQ_TYPE_COPY         1 /* mmio ops */
 #define IOREQ_TYPE_PCI_CONFIG   2
+#define IOREQ_TYPE_MEM          3
 #define IOREQ_TYPE_TIMEOFFSET   7
 #define IOREQ_TYPE_INVALIDATE   8 /* mapcache */
 
-- 
1.9.1

[PATCH v3 2/2] Refactor rangeset structure for better performance.

[Yu Zhang]

This patch refactors struct rangeset to base it on the red-black
tree structure, instead of on the current doubly linked list. By
now, ioreq leverages rangeset to keep track of the IO/memory
resources to be emulated. Yet when number of ranges inside one
ioreq server is very high, traversing a doubly linked list could
be time consuming. With this patch, the time complexity for
searching a rangeset can be improved from O(n) to O(log(n)).
Interfaces of rangeset still remain the same, and no new APIs
introduced.

Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
---
 xen/common/rangeset.c | 82 +++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 60 insertions(+), 22 deletions(-)

diff --git a/xen/common/rangeset.c b/xen/common/rangeset.c
index 6c6293c..87b6aab 100644
--- a/xen/common/rangeset.c
+++ b/xen/common/rangeset.c
@@ -10,11 +10,12 @@
 #include <xen/sched.h>
 #include <xen/errno.h>
 #include <xen/rangeset.h>
+#include <xen/rbtree.h>
 #include <xsm/xsm.h>
 
 /* An inclusive range [s,e] and pointer to next range in ascending order. */
 struct range {
-    struct list_head list;
+    struct rb_node node;
     unsigned long s, e;
 };
 
@@ -24,7 +25,7 @@ struct rangeset {
     struct domain   *domain;
 
     /* Ordered list of ranges contained in this set, and protecting lock. */
-    struct list_head range_list;
+    struct rb_root   range_tree;
 
     /* Number of ranges that can be allocated */
     long             nr_ranges;
@@ -45,41 +46,78 @@ struct rangeset {
 static struct range *find_range(
     struct rangeset *r, unsigned long s)
 {
-    struct range *x = NULL, *y;
+    struct rb_node *node;
+    struct range   *x;
+    struct range   *prev = NULL;
 
-    list_for_each_entry ( y, &r->range_list, list )
+    node = r->range_tree.rb_node;
+    while ( node )
     {
-        if ( y->s > s )
-            break;
-        x = y;
+        x = container_of(node, struct range, node);
+        if ( (s >= x->s) && (s <= x->e) )
+            return x;
+        if ( s < x->s )
+            node = node->rb_left;
+        else if ( s > x->s )
+        {
+            prev = x;
+            node = node->rb_right;
+        }
     }
 
-    return x;
+    return prev;
 }
 
 /* Return the lowest range in the set r, or NULL if r is empty. */
 static struct range *first_range(
     struct rangeset *r)
 {
-    if ( list_empty(&r->range_list) )
-        return NULL;
-    return list_entry(r->range_list.next, struct range, list);
+    struct rb_node *node;
+
+    node = rb_first(&r->range_tree);
+    if ( node != NULL )
+        return container_of(node, struct range, node);
+
+    return NULL;
 }
 
 /* Return range following x in ascending order, or NULL if x is the highest. */
 static struct range *next_range(
     struct rangeset *r, struct range *x)
 {
-    if ( x->list.next == &r->range_list )
-        return NULL;
-    return list_entry(x->list.next, struct range, list);
+    struct rb_node *node;
+
+    node = rb_next(&x->node);
+    if ( node )
+        return container_of(node, struct range, node);
+
+    return NULL;
 }
 
 /* Insert range y after range x in r. Insert as first range if x is NULL. */
 static void insert_range(
     struct rangeset *r, struct range *x, struct range *y)
 {
-    list_add(&y->list, (x != NULL) ? &x->list : &r->range_list);
+    struct rb_node **node;
+    struct rb_node *parent = NULL;
+
+    if ( x == NULL )
+        node = &r->range_tree.rb_node;
+    else
+    {
+        node = &x->node.rb_right;
+        parent = &x->node;
+    }
+
+    while ( *node )
+    {
+        parent = *node;
+        node = &parent->rb_left;
+    }
+
+    /* Add new node and rebalance the red-black tree. */
+    rb_link_node(&y->node, parent, node);
+    rb_insert_color(&y->node, &r->range_tree);
 }
 
 /* Remove a range from its list and free it. */
@@ -88,7 +126,7 @@ static void destroy_range(
 {
     r->nr_ranges++;
 
-    list_del(&x->list);
+    rb_erase(&x->node, &r->range_tree);
     xfree(x);
 }
 
@@ -319,7 +357,7 @@ bool_t rangeset_contains_singleton(
 bool_t rangeset_is_empty(
     const struct rangeset *r)
 {
-    return ((r == NULL) || list_empty(&r->range_list));
+    return ((r == NULL) || RB_EMPTY_ROOT(&r->range_tree));
 }
 
 struct rangeset *rangeset_new(
@@ -332,7 +370,7 @@ struct rangeset *rangeset_new(
         return NULL;
 
     rwlock_init(&r->lock);
-    INIT_LIST_HEAD(&r->range_list);
+    r->range_tree = RB_ROOT;
     r->nr_ranges = -1;
 
     BUG_ON(flags & ~RANGESETF_prettyprint_hex);
@@ -410,7 +448,7 @@ void rangeset_domain_destroy(
 
 void rangeset_swap(struct rangeset *a, struct rangeset *b)
 {
-    LIST_HEAD(tmp);
+    struct rb_node* tmp;
 
     if ( a < b )
     {
@@ -423,9 +461,9 @@ void rangeset_swap(struct rangeset *a, struct rangeset *b)
         write_lock(&a->lock);
     }
 
-    list_splice_init(&a->range_list, &tmp);
-    list_splice_init(&b->range_list, &a->range_list);
-    list_splice(&tmp, &b->range_list);
+    tmp = a->range_tree.rb_node;
+    a->range_tree.rb_node = b->range_tree.rb_node;
+    b->range_tree.rb_node = tmp;
 
     write_unlock(&a->lock);
     write_unlock(&b->lock);
-- 
1.9.1

Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by ioreq server

[Wei Liu]

On Mon, Aug 10, 2015 at 11:33:40AM +0800, Yu Zhang wrote:
> Currently in ioreq server, guest write-protected ram pages are
> tracked in the same rangeset with device mmio resources. Yet
> unlike device mmio, which can be in big chunks, the guest write-
> protected pages may be discrete ranges with 4K bytes each.
> 
> This patch uses a seperate rangeset for the guest ram pages.
> And a new ioreq type, IOREQ_TYPE_MEM, is defined.
> 
> Note: Previously, a new hypercall or subop was suggested to map
> write-protected pages into ioreq server. However, it turned out
> handler of this new hypercall would be almost the same with the
> existing pair - HVMOP_[un]map_io_range_to_ioreq_server, and there's
> already a type parameter in this hypercall. So no new hypercall
> defined, only a new type is introduced.
> 
> Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
> ---
>  tools/libxc/include/xenctrl.h    | 39 +++++++++++++++++++++++---
>  tools/libxc/xc_domain.c          | 59 ++++++++++++++++++++++++++++++++++++++--

FWIW the hypercall wrappers look correct to me.

> diff --git a/xen/include/public/hvm/hvm_op.h b/xen/include/public/hvm/hvm_op.h
> index 014546a..9106cb9 100644
> --- a/xen/include/public/hvm/hvm_op.h
> +++ b/xen/include/public/hvm/hvm_op.h
> @@ -329,8 +329,9 @@ struct xen_hvm_io_range {
>      ioservid_t id;               /* IN - server id */
>      uint32_t type;               /* IN - type of range */
>  # define HVMOP_IO_RANGE_PORT   0 /* I/O port range */
> -# define HVMOP_IO_RANGE_MEMORY 1 /* MMIO range */
> +# define HVMOP_IO_RANGE_MMIO   1 /* MMIO range */
>  # define HVMOP_IO_RANGE_PCI    2 /* PCI segment/bus/dev/func range */
> +# define HVMOP_IO_RANGE_MEMORY 3 /* MEMORY range */

This looks problematic. Maybe you can get away with this because this is
a toolstack-only interface?

Wei.

Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by ioreq server

[Paul Durrant]

> -----Original Message-----
> From: Wei Liu [mailto:wei.liu2@citrix.com]
> Sent: 10 August 2015 09:26
> To: Yu Zhang
> Cc: xen-devel@lists.xen.org; Paul Durrant; Ian Jackson; Stefano Stabellini; Ian
> Campbell; Wei Liu; Keir (Xen.org); jbeulich@suse.com; Andrew Cooper;
> Kevin Tian; zhiyuan.lv@intel.com
> Subject: Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by ioreq
> server
> 
> On Mon, Aug 10, 2015 at 11:33:40AM +0800, Yu Zhang wrote:
> > Currently in ioreq server, guest write-protected ram pages are
> > tracked in the same rangeset with device mmio resources. Yet
> > unlike device mmio, which can be in big chunks, the guest write-
> > protected pages may be discrete ranges with 4K bytes each.
> >
> > This patch uses a seperate rangeset for the guest ram pages.
> > And a new ioreq type, IOREQ_TYPE_MEM, is defined.
> >
> > Note: Previously, a new hypercall or subop was suggested to map
> > write-protected pages into ioreq server. However, it turned out
> > handler of this new hypercall would be almost the same with the
> > existing pair - HVMOP_[un]map_io_range_to_ioreq_server, and there's
> > already a type parameter in this hypercall. So no new hypercall
> > defined, only a new type is introduced.
> >
> > Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
> > ---
> >  tools/libxc/include/xenctrl.h    | 39 +++++++++++++++++++++++---
> >  tools/libxc/xc_domain.c          | 59
> ++++++++++++++++++++++++++++++++++++++--
> 
> FWIW the hypercall wrappers look correct to me.
> 
> > diff --git a/xen/include/public/hvm/hvm_op.h
> b/xen/include/public/hvm/hvm_op.h
> > index 014546a..9106cb9 100644
> > --- a/xen/include/public/hvm/hvm_op.h
> > +++ b/xen/include/public/hvm/hvm_op.h
> > @@ -329,8 +329,9 @@ struct xen_hvm_io_range {
> >      ioservid_t id;               /* IN - server id */
> >      uint32_t type;               /* IN - type of range */
> >  # define HVMOP_IO_RANGE_PORT   0 /* I/O port range */
> > -# define HVMOP_IO_RANGE_MEMORY 1 /* MMIO range */
> > +# define HVMOP_IO_RANGE_MMIO   1 /* MMIO range */
> >  # define HVMOP_IO_RANGE_PCI    2 /* PCI segment/bus/dev/func range
> */
> > +# define HVMOP_IO_RANGE_MEMORY 3 /* MEMORY range */
> 
> This looks problematic. Maybe you can get away with this because this is
> a toolstack-only interface?
> 

Indeed, the old name is a bit problematic. Presumably re-use like this would require an interface version change and some if-defery.

  Paul

> Wei.

Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by ioreq server

[Andrew Cooper]

On 10/08/15 09:33, Paul Durrant wrote:
>> -----Original Message-----
>> From: Wei Liu [mailto:wei.liu2@citrix.com]
>> Sent: 10 August 2015 09:26
>> To: Yu Zhang
>> Cc: xen-devel@lists.xen.org; Paul Durrant; Ian Jackson; Stefano Stabellini; Ian
>> Campbell; Wei Liu; Keir (Xen.org); jbeulich@suse.com; Andrew Cooper;
>> Kevin Tian; zhiyuan.lv@intel.com
>> Subject: Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by ioreq
>> server
>>
>> On Mon, Aug 10, 2015 at 11:33:40AM +0800, Yu Zhang wrote:
>>> Currently in ioreq server, guest write-protected ram pages are
>>> tracked in the same rangeset with device mmio resources. Yet
>>> unlike device mmio, which can be in big chunks, the guest write-
>>> protected pages may be discrete ranges with 4K bytes each.
>>>
>>> This patch uses a seperate rangeset for the guest ram pages.
>>> And a new ioreq type, IOREQ_TYPE_MEM, is defined.
>>>
>>> Note: Previously, a new hypercall or subop was suggested to map
>>> write-protected pages into ioreq server. However, it turned out
>>> handler of this new hypercall would be almost the same with the
>>> existing pair - HVMOP_[un]map_io_range_to_ioreq_server, and there's
>>> already a type parameter in this hypercall. So no new hypercall
>>> defined, only a new type is introduced.
>>>
>>> Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
>>> ---
>>>  tools/libxc/include/xenctrl.h    | 39 +++++++++++++++++++++++---
>>>  tools/libxc/xc_domain.c          | 59
>> ++++++++++++++++++++++++++++++++++++++--
>>
>> FWIW the hypercall wrappers look correct to me.
>>
>>> diff --git a/xen/include/public/hvm/hvm_op.h
>> b/xen/include/public/hvm/hvm_op.h
>>> index 014546a..9106cb9 100644
>>> --- a/xen/include/public/hvm/hvm_op.h
>>> +++ b/xen/include/public/hvm/hvm_op.h
>>> @@ -329,8 +329,9 @@ struct xen_hvm_io_range {
>>>      ioservid_t id;               /* IN - server id */
>>>      uint32_t type;               /* IN - type of range */
>>>  # define HVMOP_IO_RANGE_PORT   0 /* I/O port range */
>>> -# define HVMOP_IO_RANGE_MEMORY 1 /* MMIO range */
>>> +# define HVMOP_IO_RANGE_MMIO   1 /* MMIO range */
>>>  # define HVMOP_IO_RANGE_PCI    2 /* PCI segment/bus/dev/func range
>> */
>>> +# define HVMOP_IO_RANGE_MEMORY 3 /* MEMORY range */
>> This looks problematic. Maybe you can get away with this because this is
>> a toolstack-only interface?
>>
> Indeed, the old name is a bit problematic. Presumably re-use like this would require an interface version change and some if-defery.

I assume it is an interface used by qemu, so this patch in its currently
state will break things.

~Andrew

Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by ioreq server

[Paul Durrant]

> -----Original Message-----
> From: Andrew Cooper [mailto:andrew.cooper3@citrix.com]
> Sent: 10 August 2015 11:56
> To: Paul Durrant; Wei Liu; Yu Zhang
> Cc: xen-devel@lists.xen.org; Ian Jackson; Stefano Stabellini; Ian Campbell;
> Keir (Xen.org); jbeulich@suse.com; Kevin Tian; zhiyuan.lv@intel.com
> Subject: Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by ioreq
> server
> 
> On 10/08/15 09:33, Paul Durrant wrote:
> >> -----Original Message-----
> >> From: Wei Liu [mailto:wei.liu2@citrix.com]
> >> Sent: 10 August 2015 09:26
> >> To: Yu Zhang
> >> Cc: xen-devel@lists.xen.org; Paul Durrant; Ian Jackson; Stefano Stabellini;
> Ian
> >> Campbell; Wei Liu; Keir (Xen.org); jbeulich@suse.com; Andrew Cooper;
> >> Kevin Tian; zhiyuan.lv@intel.com
> >> Subject: Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by
> ioreq
> >> server
> >>
> >> On Mon, Aug 10, 2015 at 11:33:40AM +0800, Yu Zhang wrote:
> >>> Currently in ioreq server, guest write-protected ram pages are
> >>> tracked in the same rangeset with device mmio resources. Yet
> >>> unlike device mmio, which can be in big chunks, the guest write-
> >>> protected pages may be discrete ranges with 4K bytes each.
> >>>
> >>> This patch uses a seperate rangeset for the guest ram pages.
> >>> And a new ioreq type, IOREQ_TYPE_MEM, is defined.
> >>>
> >>> Note: Previously, a new hypercall or subop was suggested to map
> >>> write-protected pages into ioreq server. However, it turned out
> >>> handler of this new hypercall would be almost the same with the
> >>> existing pair - HVMOP_[un]map_io_range_to_ioreq_server, and there's
> >>> already a type parameter in this hypercall. So no new hypercall
> >>> defined, only a new type is introduced.
> >>>
> >>> Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
> >>> ---
> >>>  tools/libxc/include/xenctrl.h    | 39 +++++++++++++++++++++++---
> >>>  tools/libxc/xc_domain.c          | 59
> >> ++++++++++++++++++++++++++++++++++++++--
> >>
> >> FWIW the hypercall wrappers look correct to me.
> >>
> >>> diff --git a/xen/include/public/hvm/hvm_op.h
> >> b/xen/include/public/hvm/hvm_op.h
> >>> index 014546a..9106cb9 100644
> >>> --- a/xen/include/public/hvm/hvm_op.h
> >>> +++ b/xen/include/public/hvm/hvm_op.h
> >>> @@ -329,8 +329,9 @@ struct xen_hvm_io_range {
> >>>      ioservid_t id;               /* IN - server id */
> >>>      uint32_t type;               /* IN - type of range */
> >>>  # define HVMOP_IO_RANGE_PORT   0 /* I/O port range */
> >>> -# define HVMOP_IO_RANGE_MEMORY 1 /* MMIO range */
> >>> +# define HVMOP_IO_RANGE_MMIO   1 /* MMIO range */
> >>>  # define HVMOP_IO_RANGE_PCI    2 /* PCI segment/bus/dev/func
> range
> >> */
> >>> +# define HVMOP_IO_RANGE_MEMORY 3 /* MEMORY range */
> >> This looks problematic. Maybe you can get away with this because this is
> >> a toolstack-only interface?
> >>
> > Indeed, the old name is a bit problematic. Presumably re-use like this
> would require an interface version change and some if-defery.
> 
> I assume it is an interface used by qemu, so this patch in its currently
> state will break things.

If QEMU were re-built against the updated header, yes.

  Paul

> 
> ~Andrew

Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by ioreq server

[Yu, Zhang]

On 8/10/2015 4:26 PM, Wei Liu wrote:
> On Mon, Aug 10, 2015 at 11:33:40AM +0800, Yu Zhang wrote:
>> Currently in ioreq server, guest write-protected ram pages are
>> tracked in the same rangeset with device mmio resources. Yet
>> unlike device mmio, which can be in big chunks, the guest write-
>> protected pages may be discrete ranges with 4K bytes each.
>>
>> This patch uses a seperate rangeset for the guest ram pages.
>> And a new ioreq type, IOREQ_TYPE_MEM, is defined.
>>
>> Note: Previously, a new hypercall or subop was suggested to map
>> write-protected pages into ioreq server. However, it turned out
>> handler of this new hypercall would be almost the same with the
>> existing pair - HVMOP_[un]map_io_range_to_ioreq_server, and there's
>> already a type parameter in this hypercall. So no new hypercall
>> defined, only a new type is introduced.
>>
>> Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
>> ---
>>   tools/libxc/include/xenctrl.h    | 39 +++++++++++++++++++++++---
>>   tools/libxc/xc_domain.c          | 59 ++++++++++++++++++++++++++++++++++++++--
>
> FWIW the hypercall wrappers look correct to me.
>
>> diff --git a/xen/include/public/hvm/hvm_op.h b/xen/include/public/hvm/hvm_op.h
>> index 014546a..9106cb9 100644
>> --- a/xen/include/public/hvm/hvm_op.h
>> +++ b/xen/include/public/hvm/hvm_op.h
>> @@ -329,8 +329,9 @@ struct xen_hvm_io_range {
>>       ioservid_t id;               /* IN - server id */
>>       uint32_t type;               /* IN - type of range */
>>   # define HVMOP_IO_RANGE_PORT   0 /* I/O port range */
>> -# define HVMOP_IO_RANGE_MEMORY 1 /* MMIO range */
>> +# define HVMOP_IO_RANGE_MMIO   1 /* MMIO range */
>>   # define HVMOP_IO_RANGE_PCI    2 /* PCI segment/bus/dev/func range */
>> +# define HVMOP_IO_RANGE_MEMORY 3 /* MEMORY range */
>
> This looks problematic. Maybe you can get away with this because this is
> a toolstack-only interface?
>
Thanks Wei.
Well, I believe this interface could be used both by the backend device
driver and qemu as well(which I neglected).  :-)

Yu

> Wei.
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
>
>

Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by ioreq server

[Yu, Zhang]

On 8/10/2015 6:57 PM, Paul Durrant wrote:
>> -----Original Message-----
>> From: Andrew Cooper [mailto:andrew.cooper3@citrix.com]
>> Sent: 10 August 2015 11:56
>> To: Paul Durrant; Wei Liu; Yu Zhang
>> Cc: xen-devel@lists.xen.org; Ian Jackson; Stefano Stabellini; Ian Campbell;
>> Keir (Xen.org); jbeulich@suse.com; Kevin Tian; zhiyuan.lv@intel.com
>> Subject: Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by ioreq
>> server
>>
>> On 10/08/15 09:33, Paul Durrant wrote:
>>>> -----Original Message-----
>>>> From: Wei Liu [mailto:wei.liu2@citrix.com]
>>>> Sent: 10 August 2015 09:26
>>>> To: Yu Zhang
>>>> Cc: xen-devel@lists.xen.org; Paul Durrant; Ian Jackson; Stefano Stabellini;
>> Ian
>>>> Campbell; Wei Liu; Keir (Xen.org); jbeulich@suse.com; Andrew Cooper;
>>>> Kevin Tian; zhiyuan.lv@intel.com
>>>> Subject: Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by
>> ioreq
>>>> server
>>>>
>>>> On Mon, Aug 10, 2015 at 11:33:40AM +0800, Yu Zhang wrote:
>>>>> Currently in ioreq server, guest write-protected ram pages are
>>>>> tracked in the same rangeset with device mmio resources. Yet
>>>>> unlike device mmio, which can be in big chunks, the guest write-
>>>>> protected pages may be discrete ranges with 4K bytes each.
>>>>>
>>>>> This patch uses a seperate rangeset for the guest ram pages.
>>>>> And a new ioreq type, IOREQ_TYPE_MEM, is defined.
>>>>>
>>>>> Note: Previously, a new hypercall or subop was suggested to map
>>>>> write-protected pages into ioreq server. However, it turned out
>>>>> handler of this new hypercall would be almost the same with the
>>>>> existing pair - HVMOP_[un]map_io_range_to_ioreq_server, and there's
>>>>> already a type parameter in this hypercall. So no new hypercall
>>>>> defined, only a new type is introduced.
>>>>>
>>>>> Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
>>>>> ---
>>>>>   tools/libxc/include/xenctrl.h    | 39 +++++++++++++++++++++++---
>>>>>   tools/libxc/xc_domain.c          | 59
>>>> ++++++++++++++++++++++++++++++++++++++--
>>>>
>>>> FWIW the hypercall wrappers look correct to me.
>>>>
>>>>> diff --git a/xen/include/public/hvm/hvm_op.h
>>>> b/xen/include/public/hvm/hvm_op.h
>>>>> index 014546a..9106cb9 100644
>>>>> --- a/xen/include/public/hvm/hvm_op.h
>>>>> +++ b/xen/include/public/hvm/hvm_op.h
>>>>> @@ -329,8 +329,9 @@ struct xen_hvm_io_range {
>>>>>       ioservid_t id;               /* IN - server id */
>>>>>       uint32_t type;               /* IN - type of range */
>>>>>   # define HVMOP_IO_RANGE_PORT   0 /* I/O port range */
>>>>> -# define HVMOP_IO_RANGE_MEMORY 1 /* MMIO range */
>>>>> +# define HVMOP_IO_RANGE_MMIO   1 /* MMIO range */
>>>>>   # define HVMOP_IO_RANGE_PCI    2 /* PCI segment/bus/dev/func
>> range
>>>> */
>>>>> +# define HVMOP_IO_RANGE_MEMORY 3 /* MEMORY range */
>>>> This looks problematic. Maybe you can get away with this because this is
>>>> a toolstack-only interface?
>>>>
>>> Indeed, the old name is a bit problematic. Presumably re-use like this
>> would require an interface version change and some if-defery.
>>
>> I assume it is an interface used by qemu, so this patch in its currently
>> state will break things.
>
> If QEMU were re-built against the updated header, yes.

Thank you, Andrew & Paul. :)
Are you referring to the xen_map/unmap_memory_section routines in QEMU?
I noticed they are called by xen_region_add/del in QEMU. And I wonder,
are these 2 routines used to track a memory region or to track a MMIO
region? If the region to be added is a MMIO, I guess the new interface
should be fine, but if it is memory region to be added into ioreq
server, maybe a patch in QEMU is necessary(e.g. use some if-defery for
this new interface version you suggested)?

Thanks
Yu
>
>    Paul
>
>>
>> ~Andrew
>

Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by ioreq server

[Paul Durrant]

> -----Original Message-----
> From: Yu, Zhang [mailto:yu.c.zhang@linux.intel.com]
> Sent: 11 August 2015 08:57
> To: Paul Durrant; Andrew Cooper; Wei Liu
> Cc: xen-devel@lists.xen.org; Ian Jackson; Stefano Stabellini; Ian Campbell;
> Keir (Xen.org); jbeulich@suse.com; Kevin Tian; zhiyuan.lv@intel.com
> Subject: Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by ioreq
> server
> 
> 
> 
> On 8/10/2015 6:57 PM, Paul Durrant wrote:
> >> -----Original Message-----
> >> From: Andrew Cooper [mailto:andrew.cooper3@citrix.com]
> >> Sent: 10 August 2015 11:56
> >> To: Paul Durrant; Wei Liu; Yu Zhang
> >> Cc: xen-devel@lists.xen.org; Ian Jackson; Stefano Stabellini; Ian Campbell;
> >> Keir (Xen.org); jbeulich@suse.com; Kevin Tian; zhiyuan.lv@intel.com
> >> Subject: Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by
> ioreq
> >> server
> >>
> >> On 10/08/15 09:33, Paul Durrant wrote:
> >>>> -----Original Message-----
> >>>> From: Wei Liu [mailto:wei.liu2@citrix.com]
> >>>> Sent: 10 August 2015 09:26
> >>>> To: Yu Zhang
> >>>> Cc: xen-devel@lists.xen.org; Paul Durrant; Ian Jackson; Stefano
> Stabellini;
> >> Ian
> >>>> Campbell; Wei Liu; Keir (Xen.org); jbeulich@suse.com; Andrew Cooper;
> >>>> Kevin Tian; zhiyuan.lv@intel.com
> >>>> Subject: Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by
> >> ioreq
> >>>> server
> >>>>
> >>>> On Mon, Aug 10, 2015 at 11:33:40AM +0800, Yu Zhang wrote:
> >>>>> Currently in ioreq server, guest write-protected ram pages are
> >>>>> tracked in the same rangeset with device mmio resources. Yet
> >>>>> unlike device mmio, which can be in big chunks, the guest write-
> >>>>> protected pages may be discrete ranges with 4K bytes each.
> >>>>>
> >>>>> This patch uses a seperate rangeset for the guest ram pages.
> >>>>> And a new ioreq type, IOREQ_TYPE_MEM, is defined.
> >>>>>
> >>>>> Note: Previously, a new hypercall or subop was suggested to map
> >>>>> write-protected pages into ioreq server. However, it turned out
> >>>>> handler of this new hypercall would be almost the same with the
> >>>>> existing pair - HVMOP_[un]map_io_range_to_ioreq_server, and
> there's
> >>>>> already a type parameter in this hypercall. So no new hypercall
> >>>>> defined, only a new type is introduced.
> >>>>>
> >>>>> Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
> >>>>> ---
> >>>>>   tools/libxc/include/xenctrl.h    | 39 +++++++++++++++++++++++---
> >>>>>   tools/libxc/xc_domain.c          | 59
> >>>> ++++++++++++++++++++++++++++++++++++++--
> >>>>
> >>>> FWIW the hypercall wrappers look correct to me.
> >>>>
> >>>>> diff --git a/xen/include/public/hvm/hvm_op.h
> >>>> b/xen/include/public/hvm/hvm_op.h
> >>>>> index 014546a..9106cb9 100644
> >>>>> --- a/xen/include/public/hvm/hvm_op.h
> >>>>> +++ b/xen/include/public/hvm/hvm_op.h
> >>>>> @@ -329,8 +329,9 @@ struct xen_hvm_io_range {
> >>>>>       ioservid_t id;               /* IN - server id */
> >>>>>       uint32_t type;               /* IN - type of range */
> >>>>>   # define HVMOP_IO_RANGE_PORT   0 /* I/O port range */
> >>>>> -# define HVMOP_IO_RANGE_MEMORY 1 /* MMIO range */
> >>>>> +# define HVMOP_IO_RANGE_MMIO   1 /* MMIO range */
> >>>>>   # define HVMOP_IO_RANGE_PCI    2 /* PCI segment/bus/dev/func
> >> range
> >>>> */
> >>>>> +# define HVMOP_IO_RANGE_MEMORY 3 /* MEMORY range */
> >>>> This looks problematic. Maybe you can get away with this because this
> is
> >>>> a toolstack-only interface?
> >>>>
> >>> Indeed, the old name is a bit problematic. Presumably re-use like this
> >> would require an interface version change and some if-defery.
> >>
> >> I assume it is an interface used by qemu, so this patch in its currently
> >> state will break things.
> >
> > If QEMU were re-built against the updated header, yes.
> 
> Thank you, Andrew & Paul. :)
> Are you referring to the xen_map/unmap_memory_section routines in
> QEMU?
> I noticed they are called by xen_region_add/del in QEMU. And I wonder,
> are these 2 routines used to track a memory region or to track a MMIO
> region? If the region to be added is a MMIO, I guess the new interface
> should be fine, but if it is memory region to be added into ioreq
> server, maybe a patch in QEMU is necessary(e.g. use some if-defery for
> this new interface version you suggested)?
> 

I was forgetting that QEMU uses libxenctrl so your change to xc_hvm_map_io_range_to_ioreq_server() means everything will continue to work as before. There is still the (admittedly academic) problem of some unknown emulator out there that rolls its own hypercalls and blindly updates to the new version of hvm_op.h suddenly starting to register memory ranges rather than mmio ranges though. I would leave the existing definitions as-is and come up with a new name.

  Paul

> Thanks
> Yu
> >
> >    Paul
> >
> >>
> >> ~Andrew
> >

Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by ioreq server

[Yu, Zhang]

On 8/11/2015 4:25 PM, Paul Durrant wrote:
>> -----Original Message-----
>> From: Yu, Zhang [mailto:yu.c.zhang@linux.intel.com]
>> Sent: 11 August 2015 08:57
>> To: Paul Durrant; Andrew Cooper; Wei Liu
>> Cc: xen-devel@lists.xen.org; Ian Jackson; Stefano Stabellini; Ian Campbell;
>> Keir (Xen.org); jbeulich@suse.com; Kevin Tian; zhiyuan.lv@intel.com
>> Subject: Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by ioreq
>> server
>>
>>
>>
>> On 8/10/2015 6:57 PM, Paul Durrant wrote:
>>>> -----Original Message-----
>>>> From: Andrew Cooper [mailto:andrew.cooper3@citrix.com]
>>>> Sent: 10 August 2015 11:56
>>>> To: Paul Durrant; Wei Liu; Yu Zhang
>>>> Cc: xen-devel@lists.xen.org; Ian Jackson; Stefano Stabellini; Ian Campbell;
>>>> Keir (Xen.org); jbeulich@suse.com; Kevin Tian; zhiyuan.lv@intel.com
>>>> Subject: Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by
>> ioreq
>>>> server
>>>>
>>>> On 10/08/15 09:33, Paul Durrant wrote:
>>>>>> -----Original Message-----
>>>>>> From: Wei Liu [mailto:wei.liu2@citrix.com]
>>>>>> Sent: 10 August 2015 09:26
>>>>>> To: Yu Zhang
>>>>>> Cc: xen-devel@lists.xen.org; Paul Durrant; Ian Jackson; Stefano
>> Stabellini;
>>>> Ian
>>>>>> Campbell; Wei Liu; Keir (Xen.org); jbeulich@suse.com; Andrew Cooper;
>>>>>> Kevin Tian; zhiyuan.lv@intel.com
>>>>>> Subject: Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by
>>>> ioreq
>>>>>> server
>>>>>>
>>>>>> On Mon, Aug 10, 2015 at 11:33:40AM +0800, Yu Zhang wrote:
>>>>>>> Currently in ioreq server, guest write-protected ram pages are
>>>>>>> tracked in the same rangeset with device mmio resources. Yet
>>>>>>> unlike device mmio, which can be in big chunks, the guest write-
>>>>>>> protected pages may be discrete ranges with 4K bytes each.
>>>>>>>
>>>>>>> This patch uses a seperate rangeset for the guest ram pages.
>>>>>>> And a new ioreq type, IOREQ_TYPE_MEM, is defined.
>>>>>>>
>>>>>>> Note: Previously, a new hypercall or subop was suggested to map
>>>>>>> write-protected pages into ioreq server. However, it turned out
>>>>>>> handler of this new hypercall would be almost the same with the
>>>>>>> existing pair - HVMOP_[un]map_io_range_to_ioreq_server, and
>> there's
>>>>>>> already a type parameter in this hypercall. So no new hypercall
>>>>>>> defined, only a new type is introduced.
>>>>>>>
>>>>>>> Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
>>>>>>> ---
>>>>>>>    tools/libxc/include/xenctrl.h    | 39 +++++++++++++++++++++++---
>>>>>>>    tools/libxc/xc_domain.c          | 59
>>>>>> ++++++++++++++++++++++++++++++++++++++--
>>>>>>
>>>>>> FWIW the hypercall wrappers look correct to me.
>>>>>>
>>>>>>> diff --git a/xen/include/public/hvm/hvm_op.h
>>>>>> b/xen/include/public/hvm/hvm_op.h
>>>>>>> index 014546a..9106cb9 100644
>>>>>>> --- a/xen/include/public/hvm/hvm_op.h
>>>>>>> +++ b/xen/include/public/hvm/hvm_op.h
>>>>>>> @@ -329,8 +329,9 @@ struct xen_hvm_io_range {
>>>>>>>        ioservid_t id;               /* IN - server id */
>>>>>>>        uint32_t type;               /* IN - type of range */
>>>>>>>    # define HVMOP_IO_RANGE_PORT   0 /* I/O port range */
>>>>>>> -# define HVMOP_IO_RANGE_MEMORY 1 /* MMIO range */
>>>>>>> +# define HVMOP_IO_RANGE_MMIO   1 /* MMIO range */
>>>>>>>    # define HVMOP_IO_RANGE_PCI    2 /* PCI segment/bus/dev/func
>>>> range
>>>>>> */
>>>>>>> +# define HVMOP_IO_RANGE_MEMORY 3 /* MEMORY range */
>>>>>> This looks problematic. Maybe you can get away with this because this
>> is
>>>>>> a toolstack-only interface?
>>>>>>
>>>>> Indeed, the old name is a bit problematic. Presumably re-use like this
>>>> would require an interface version change and some if-defery.
>>>>
>>>> I assume it is an interface used by qemu, so this patch in its currently
>>>> state will break things.
>>>
>>> If QEMU were re-built against the updated header, yes.
>>
>> Thank you, Andrew & Paul. :)
>> Are you referring to the xen_map/unmap_memory_section routines in
>> QEMU?
>> I noticed they are called by xen_region_add/del in QEMU. And I wonder,
>> are these 2 routines used to track a memory region or to track a MMIO
>> region? If the region to be added is a MMIO, I guess the new interface
>> should be fine, but if it is memory region to be added into ioreq
>> server, maybe a patch in QEMU is necessary(e.g. use some if-defery for
>> this new interface version you suggested)?
>>
>
> I was forgetting that QEMU uses libxenctrl so your change to xc_hvm_map_io_range_to_ioreq_server() means everything will continue to work as before. There is still the (admittedly academic) problem of some unknown emulator out there that rolls its own hypercalls and blindly updates to the new version of hvm_op.h suddenly starting to register memory ranges rather than mmio ranges though. I would leave the existing definitions as-is and come up with a new name.

So, how about we keep the  HVMOP_IO_RANGE_MEMORY name for MMIO, and use
a new one, say HVMOP_IO_RANGE_WP_MEM, for write-protected rams only? :)

Thanks
Yu

>
>    Paul
>
>> Thanks
>> Yu
>>>
>>>     Paul
>>>
>>>>
>>>> ~Andrew
>>>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
>
>

Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by ioreq server

[Paul Durrant]

> -----Original Message-----
> From: Yu, Zhang [mailto:yu.c.zhang@linux.intel.com]
> Sent: 11 August 2015 09:41
> To: Paul Durrant; Andrew Cooper; Wei Liu
> Cc: Kevin Tian; Keir (Xen.org); Ian Campbell; xen-devel@lists.xen.org;
> Stefano Stabellini; zhiyuan.lv@intel.com; jbeulich@suse.com; Ian Jackson
> Subject: Re: [Xen-devel] [PATCH v3 1/2] Differentiate IO/mem resources
> tracked by ioreq server
> 
> 
> 
> On 8/11/2015 4:25 PM, Paul Durrant wrote:
> >> -----Original Message-----
> >> From: Yu, Zhang [mailto:yu.c.zhang@linux.intel.com]
> >> Sent: 11 August 2015 08:57
> >> To: Paul Durrant; Andrew Cooper; Wei Liu
> >> Cc: xen-devel@lists.xen.org; Ian Jackson; Stefano Stabellini; Ian Campbell;
> >> Keir (Xen.org); jbeulich@suse.com; Kevin Tian; zhiyuan.lv@intel.com
> >> Subject: Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by
> ioreq
> >> server
> >>
> >>
> >>
> >> On 8/10/2015 6:57 PM, Paul Durrant wrote:
> >>>> -----Original Message-----
> >>>> From: Andrew Cooper [mailto:andrew.cooper3@citrix.com]
> >>>> Sent: 10 August 2015 11:56
> >>>> To: Paul Durrant; Wei Liu; Yu Zhang
> >>>> Cc: xen-devel@lists.xen.org; Ian Jackson; Stefano Stabellini; Ian
> Campbell;
> >>>> Keir (Xen.org); jbeulich@suse.com; Kevin Tian; zhiyuan.lv@intel.com
> >>>> Subject: Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked by
> >> ioreq
> >>>> server
> >>>>
> >>>> On 10/08/15 09:33, Paul Durrant wrote:
> >>>>>> -----Original Message-----
> >>>>>> From: Wei Liu [mailto:wei.liu2@citrix.com]
> >>>>>> Sent: 10 August 2015 09:26
> >>>>>> To: Yu Zhang
> >>>>>> Cc: xen-devel@lists.xen.org; Paul Durrant; Ian Jackson; Stefano
> >> Stabellini;
> >>>> Ian
> >>>>>> Campbell; Wei Liu; Keir (Xen.org); jbeulich@suse.com; Andrew
> Cooper;
> >>>>>> Kevin Tian; zhiyuan.lv@intel.com
> >>>>>> Subject: Re: [PATCH v3 1/2] Differentiate IO/mem resources tracked
> by
> >>>> ioreq
> >>>>>> server
> >>>>>>
> >>>>>> On Mon, Aug 10, 2015 at 11:33:40AM +0800, Yu Zhang wrote:
> >>>>>>> Currently in ioreq server, guest write-protected ram pages are
> >>>>>>> tracked in the same rangeset with device mmio resources. Yet
> >>>>>>> unlike device mmio, which can be in big chunks, the guest write-
> >>>>>>> protected pages may be discrete ranges with 4K bytes each.
> >>>>>>>
> >>>>>>> This patch uses a seperate rangeset for the guest ram pages.
> >>>>>>> And a new ioreq type, IOREQ_TYPE_MEM, is defined.
> >>>>>>>
> >>>>>>> Note: Previously, a new hypercall or subop was suggested to map
> >>>>>>> write-protected pages into ioreq server. However, it turned out
> >>>>>>> handler of this new hypercall would be almost the same with the
> >>>>>>> existing pair - HVMOP_[un]map_io_range_to_ioreq_server, and
> >> there's
> >>>>>>> already a type parameter in this hypercall. So no new hypercall
> >>>>>>> defined, only a new type is introduced.
> >>>>>>>
> >>>>>>> Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
> >>>>>>> ---
> >>>>>>>    tools/libxc/include/xenctrl.h    | 39 +++++++++++++++++++++++-
> --
> >>>>>>>    tools/libxc/xc_domain.c          | 59
> >>>>>> ++++++++++++++++++++++++++++++++++++++--
> >>>>>>
> >>>>>> FWIW the hypercall wrappers look correct to me.
> >>>>>>
> >>>>>>> diff --git a/xen/include/public/hvm/hvm_op.h
> >>>>>> b/xen/include/public/hvm/hvm_op.h
> >>>>>>> index 014546a..9106cb9 100644
> >>>>>>> --- a/xen/include/public/hvm/hvm_op.h
> >>>>>>> +++ b/xen/include/public/hvm/hvm_op.h
> >>>>>>> @@ -329,8 +329,9 @@ struct xen_hvm_io_range {
> >>>>>>>        ioservid_t id;               /* IN - server id */
> >>>>>>>        uint32_t type;               /* IN - type of range */
> >>>>>>>    # define HVMOP_IO_RANGE_PORT   0 /* I/O port range */
> >>>>>>> -# define HVMOP_IO_RANGE_MEMORY 1 /* MMIO range */
> >>>>>>> +# define HVMOP_IO_RANGE_MMIO   1 /* MMIO range */
> >>>>>>>    # define HVMOP_IO_RANGE_PCI    2 /* PCI
> segment/bus/dev/func
> >>>> range
> >>>>>> */
> >>>>>>> +# define HVMOP_IO_RANGE_MEMORY 3 /* MEMORY range */
> >>>>>> This looks problematic. Maybe you can get away with this because
> this
> >> is
> >>>>>> a toolstack-only interface?
> >>>>>>
> >>>>> Indeed, the old name is a bit problematic. Presumably re-use like this
> >>>> would require an interface version change and some if-defery.
> >>>>
> >>>> I assume it is an interface used by qemu, so this patch in its currently
> >>>> state will break things.
> >>>
> >>> If QEMU were re-built against the updated header, yes.
> >>
> >> Thank you, Andrew & Paul. :)
> >> Are you referring to the xen_map/unmap_memory_section routines in
> >> QEMU?
> >> I noticed they are called by xen_region_add/del in QEMU. And I wonder,
> >> are these 2 routines used to track a memory region or to track a MMIO
> >> region? If the region to be added is a MMIO, I guess the new interface
> >> should be fine, but if it is memory region to be added into ioreq
> >> server, maybe a patch in QEMU is necessary(e.g. use some if-defery for
> >> this new interface version you suggested)?
> >>
> >
> > I was forgetting that QEMU uses libxenctrl so your change to
> xc_hvm_map_io_range_to_ioreq_server() means everything will continue
> to work as before. There is still the (admittedly academic) problem of some
> unknown emulator out there that rolls its own hypercalls and blindly updates
> to the new version of hvm_op.h suddenly starting to register memory ranges
> rather than mmio ranges though. I would leave the existing definitions as-is
> and come up with a new name.
> 
> So, how about we keep the  HVMOP_IO_RANGE_MEMORY name for MMIO,
> and use
> a new one, say HVMOP_IO_RANGE_WP_MEM, for write-protected rams
> only? :)

That works for me :-)

  Paul

> 
> Thanks
> Yu
> 
> >
> >    Paul
> >
> >> Thanks
> >> Yu
> >>>
> >>>     Paul
> >>>
> >>>>
> >>>> ~Andrew
> >>>
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@lists.xen.org
> > http://lists.xen.org/xen-devel
> >
> >