[PATCH v8 3/8] dm_op: convert HVMOP_track_dirty_vram

[Paul Durrant <paul.durrant@citrix.com>]

The handle type passed to the underlying shadow and hap functions is
changed for compatibility with the new hypercall buffer.

NOTE: This patch also modifies the type of the 'nr' parameter of
      xc_hvm_track_dirty_vram() from uint64_t to uint32_t. In practice
      the value passed was always truncated to 32 bits.

Suggested-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: George Dunlap <george.dunlap@eu.citrix.com>
Acked-by: Tim Deegan <tim@xen.org>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
Cc: Ian Jackson <ian.jackson@eu.citrix.com>

v8:
- Add CHECK macro.

v4:
- Knock-on changes from compat code in dm.c. Not adding Jan's R-b since
  the patch has fundamentally changed.

v3:
- Check d->max_vcpus rather than d->vcpu, as requested by Jan.
- The handle type changes (from uint8 to void) are still necessary, hence
  omitting Jan's R-b until this is confirmed to be acceptable.

v2:
- Addressed several comments from Jan.
---
 tools/flask/policy/modules/xen.if   |  4 ++--
 tools/libxc/include/xenctrl.h       |  2 +-
 tools/libxc/xc_misc.c               | 32 +++++++++--------------------
 xen/arch/x86/hvm/dm.c               | 41 ++++++++++++++++++++++++++++++++++++-
 xen/arch/x86/hvm/hvm.c              | 41 -------------------------------------
 xen/arch/x86/mm/hap/hap.c           |  2 +-
 xen/arch/x86/mm/shadow/common.c     |  2 +-
 xen/include/asm-x86/hap.h           |  2 +-
 xen/include/asm-x86/shadow.h        |  2 +-
 xen/include/public/hvm/dm_op.h      | 18 ++++++++++++++++
 xen/include/public/hvm/hvm_op.h     | 16 ---------------
 xen/include/xlat.lst                |  1 +
 xen/xsm/flask/hooks.c               |  3 ---
 xen/xsm/flask/policy/access_vectors |  2 --
 14 files changed, 76 insertions(+), 92 deletions(-)

diff --git a/tools/flask/policy/modules/xen.if b/tools/flask/policy/modules/xen.if
index f9254c2..45e5b5f 100644
--- a/tools/flask/policy/modules/xen.if
+++ b/tools/flask/policy/modules/xen.if
@@ -58,7 +58,7 @@ define(`create_domain_common', `
 	allow $1 $2:mmu { map_read map_write adjust memorymap physmap pinpage mmuext_op updatemp };
 	allow $1 $2:grant setup;
 	allow $1 $2:hvm { cacheattr getparam hvmctl irqlevel pciroute sethvmc
-			setparam pcilevel trackdirtyvram nested altp2mhvm altp2mhvm_op send_irq };
+			setparam pcilevel nested altp2mhvm altp2mhvm_op send_irq };
 ')
 
 # create_domain(priv, target)
@@ -151,7 +151,7 @@ define(`device_model', `
 
 	allow $1 $2_target:domain { getdomaininfo shutdown };
 	allow $1 $2_target:mmu { map_read map_write adjust physmap target_hack };
-	allow $1 $2_target:hvm { getparam setparam trackdirtyvram hvmctl irqlevel pciroute pcilevel cacheattr send_irq dm };
+	allow $1 $2_target:hvm { getparam setparam hvmctl irqlevel pciroute pcilevel cacheattr send_irq dm };
 ')
 
 # make_device_model(priv, dm_dom, hvm_dom)
diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
index cf36521..0cf1b48 100644
--- a/tools/libxc/include/xenctrl.h
+++ b/tools/libxc/include/xenctrl.h
@@ -1620,7 +1620,7 @@ int xc_hvm_inject_msi(
  */
 int xc_hvm_track_dirty_vram(
     xc_interface *xch, domid_t dom,
-    uint64_t first_pfn, uint64_t nr,
+    uint64_t first_pfn, uint32_t nr,
     unsigned long *bitmap);
 
 /*
diff --git a/tools/libxc/xc_misc.c b/tools/libxc/xc_misc.c
index 06e90de..4c41d41 100644
--- a/tools/libxc/xc_misc.c
+++ b/tools/libxc/xc_misc.c
@@ -581,34 +581,22 @@ int xc_hvm_inject_msi(
 
 int xc_hvm_track_dirty_vram(
     xc_interface *xch, domid_t dom,
-    uint64_t first_pfn, uint64_t nr,
+    uint64_t first_pfn, uint32_t nr,
     unsigned long *dirty_bitmap)
 {
-    DECLARE_HYPERCALL_BOUNCE(dirty_bitmap, (nr+7) / 8, XC_HYPERCALL_BUFFER_BOUNCE_OUT);
-    DECLARE_HYPERCALL_BUFFER(struct xen_hvm_track_dirty_vram, arg);
-    int rc;
+    struct xen_dm_op op;
+    struct xen_dm_op_track_dirty_vram *data;
 
-    arg = xc_hypercall_buffer_alloc(xch, arg, sizeof(*arg));
-    if ( arg == NULL || xc_hypercall_bounce_pre(xch, dirty_bitmap) )
-    {
-        PERROR("Could not bounce memory for xc_hvm_track_dirty_vram hypercall");
-        rc = -1;
-        goto out;
-    }
+    memset(&op, 0, sizeof(op));
 
-    arg->domid     = dom;
-    arg->first_pfn = first_pfn;
-    arg->nr        = nr;
-    set_xen_guest_handle(arg->dirty_bitmap, dirty_bitmap);
+    op.op = XEN_DMOP_track_dirty_vram;
+    data = &op.u.track_dirty_vram;
 
-    rc = xencall2(xch->xcall, __HYPERVISOR_hvm_op,
-                  HVMOP_track_dirty_vram,
-                  HYPERCALL_BUFFER_AS_ARG(arg));
+    data->first_pfn = first_pfn;
+    data->nr = nr;
 
-out:
-    xc_hypercall_buffer_free(xch, arg);
-    xc_hypercall_bounce_post(xch, dirty_bitmap);
-    return rc;
+    return do_dm_op(xch, dom, 2, &op, sizeof(op),
+                    dirty_bitmap, (nr + 7) / 8);
 }
 
 int xc_hvm_modified_memory(
diff --git a/xen/arch/x86/hvm/dm.c b/xen/arch/x86/hvm/dm.c
index 74b0a4b..baa91b1 100644
--- a/xen/arch/x86/hvm/dm.c
+++ b/xen/arch/x86/hvm/dm.c
@@ -18,7 +18,9 @@
 #include <xen/hypercall.h>
 #include <xen/sched.h>
 
+#include <asm/hap.h>
 #include <asm/hvm/ioreq.h>
+#include <asm/shadow.h>
 
 #include <xsm/xsm.h>
 
@@ -52,6 +54,26 @@ static bool copy_buf_to_guest(xen_dm_op_buf_t bufs[],
     return !copy_to_guest(bufs[idx].h, src, size);
 }
 
+static int track_dirty_vram(struct domain *d, xen_pfn_t first_pfn,
+                            unsigned int nr, struct xen_dm_op_buf *buf)
+{
+    if ( nr > (GB(1) >> PAGE_SHIFT) )
+        return -EINVAL;
+
+    if ( d->is_dying )
+        return -ESRCH;
+
+    if ( !d->max_vcpus || !d->vcpu[0] )
+        return -EINVAL;
+
+    if ( ((nr + 7) / 8) > buf->size )
+        return -EINVAL;
+
+    return shadow_mode_enabled(d) ?
+        shadow_track_dirty_vram(d, first_pfn, nr, buf->h) :
+        hap_track_dirty_vram(d, first_pfn, nr, buf->h);
+}
+
 static int dm_op(domid_t domid,
                  unsigned int nr_bufs,
                  xen_dm_op_buf_t bufs[])
@@ -173,6 +195,22 @@ static int dm_op(domid_t domid,
         break;
     }
 
+    case XEN_DMOP_track_dirty_vram:
+    {
+        const struct xen_dm_op_track_dirty_vram *data =
+            &op.u.track_dirty_vram;
+
+        rc = -EINVAL;
+        if ( data->pad )
+            break;
+
+        if ( nr_bufs < 2 )
+            break;
+
+        rc = track_dirty_vram(d, data->first_pfn, data->nr, &bufs[1]);
+        break;
+    }
+
     default:
         rc = -EOPNOTSUPP;
         break;
@@ -194,8 +232,9 @@ CHECK_dm_op_get_ioreq_server_info;
 CHECK_dm_op_ioreq_server_range;
 CHECK_dm_op_set_ioreq_server_state;
 CHECK_dm_op_destroy_ioreq_server;
+CHECK_dm_op_track_dirty_vram;
 
-#define MAX_NR_BUFS 1
+#define MAX_NR_BUFS 2
 
 int compat_dm_op(domid_t domid,
                  unsigned int nr_bufs,
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 3bcaab8..8fe9e6a 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -5134,47 +5134,6 @@ long do_hvm_op(unsigned long op, XEN_GUEST_HANDLE_PARAM(void) arg)
         rc = guest_handle_is_null(arg) ? hvmop_flush_tlb_all() : -EINVAL;
         break;
 
-    case HVMOP_track_dirty_vram:
-    {
-        struct xen_hvm_track_dirty_vram a;
-        struct domain *d;
-
-        if ( copy_from_guest(&a, arg, 1) )
-            return -EFAULT;
-
-        rc = rcu_lock_remote_domain_by_id(a.domid, &d);
-        if ( rc != 0 )
-            return rc;
-
-        rc = -EINVAL;
-        if ( !is_hvm_domain(d) )
-            goto tdv_fail;
-
-        if ( a.nr > GB(1) >> PAGE_SHIFT )
-            goto tdv_fail;
-
-        rc = xsm_hvm_control(XSM_DM_PRIV, d, op);
-        if ( rc )
-            goto tdv_fail;
-
-        rc = -ESRCH;
-        if ( d->is_dying )
-            goto tdv_fail;
-
-        rc = -EINVAL;
-        if ( d->vcpu == NULL || d->vcpu[0] == NULL )
-            goto tdv_fail;
-
-        if ( shadow_mode_enabled(d) )
-            rc = shadow_track_dirty_vram(d, a.first_pfn, a.nr, a.dirty_bitmap);
-        else
-            rc = hap_track_dirty_vram(d, a.first_pfn, a.nr, a.dirty_bitmap);
-
-    tdv_fail:
-        rcu_unlock_domain(d);
-        break;
-    }
-
     case HVMOP_modified_memory:
     {
         struct xen_hvm_modified_memory a;
diff --git a/xen/arch/x86/mm/hap/hap.c b/xen/arch/x86/mm/hap/hap.c
index e6dc088..6dbb3cc 100644
--- a/xen/arch/x86/mm/hap/hap.c
+++ b/xen/arch/x86/mm/hap/hap.c
@@ -68,7 +68,7 @@
 int hap_track_dirty_vram(struct domain *d,
                          unsigned long begin_pfn,
                          unsigned long nr,
-                         XEN_GUEST_HANDLE_64(uint8) guest_dirty_bitmap)
+                         XEN_GUEST_HANDLE_PARAM(void) guest_dirty_bitmap)
 {
     long rc = 0;
     struct sh_dirty_vram *dirty_vram;
diff --git a/xen/arch/x86/mm/shadow/common.c b/xen/arch/x86/mm/shadow/common.c
index e4ccf92..a619d65 100644
--- a/xen/arch/x86/mm/shadow/common.c
+++ b/xen/arch/x86/mm/shadow/common.c
@@ -3604,7 +3604,7 @@ static void sh_clean_dirty_bitmap(struct domain *d)
 int shadow_track_dirty_vram(struct domain *d,
                             unsigned long begin_pfn,
                             unsigned long nr,
-                            XEN_GUEST_HANDLE_64(uint8) guest_dirty_bitmap)
+                            XEN_GUEST_HANDLE_PARAM(void) guest_dirty_bitmap)
 {
     int rc = 0;
     unsigned long end_pfn = begin_pfn + nr;
diff --git a/xen/include/asm-x86/hap.h b/xen/include/asm-x86/hap.h
index dedb4b1..88587c4 100644
--- a/xen/include/asm-x86/hap.h
+++ b/xen/include/asm-x86/hap.h
@@ -43,7 +43,7 @@ void  hap_vcpu_init(struct vcpu *v);
 int   hap_track_dirty_vram(struct domain *d,
                            unsigned long begin_pfn,
                            unsigned long nr,
-                           XEN_GUEST_HANDLE_64(uint8) dirty_bitmap);
+                           XEN_GUEST_HANDLE_PARAM(void) dirty_bitmap);
 
 extern const struct paging_mode *hap_paging_get_mode(struct vcpu *);
 int hap_set_allocation(struct domain *d, unsigned int pages, bool *preempted);
diff --git a/xen/include/asm-x86/shadow.h b/xen/include/asm-x86/shadow.h
index bac952f..7e1ed3b 100644
--- a/xen/include/asm-x86/shadow.h
+++ b/xen/include/asm-x86/shadow.h
@@ -63,7 +63,7 @@ int shadow_enable(struct domain *d, u32 mode);
 int shadow_track_dirty_vram(struct domain *d,
                             unsigned long first_pfn,
                             unsigned long nr,
-                            XEN_GUEST_HANDLE_64(uint8) dirty_bitmap);
+                            XEN_GUEST_HANDLE_PARAM(void) dirty_bitmap);
 
 /* Handler for shadow control ops: operations from user-space to enable
  * and disable ephemeral shadow modes (test mode and log-dirty mode) and
diff --git a/xen/include/public/hvm/dm_op.h b/xen/include/public/hvm/dm_op.h
index dcd407b..fef01d2 100644
--- a/xen/include/public/hvm/dm_op.h
+++ b/xen/include/public/hvm/dm_op.h
@@ -177,6 +177,23 @@ struct xen_dm_op_destroy_ioreq_server {
     uint16_t pad;
 };
 
+/*
+ * XEN_DMOP_track_dirty_vram: Track modifications to the specified pfn
+ *                            range.
+ *
+ * NOTE: The bitmap passed back to the caller is passed in a
+ *       secondary buffer.
+ */
+#define XEN_DMOP_track_dirty_vram 7
+
+struct xen_dm_op_track_dirty_vram {
+    /* IN - number of pages to be tracked */
+    uint32_t nr;
+    uint32_t pad;
+    /* IN - first pfn to track */
+    uint64_aligned_t first_pfn;
+};
+
 struct xen_dm_op {
     uint32_t op;
     uint32_t pad;
@@ -187,6 +204,7 @@ struct xen_dm_op {
         struct xen_dm_op_ioreq_server_range unmap_io_range_from_ioreq_server;
         struct xen_dm_op_set_ioreq_server_state set_ioreq_server_state;
         struct xen_dm_op_destroy_ioreq_server destroy_ioreq_server;
+        struct xen_dm_op_track_dirty_vram track_dirty_vram;
     } u;
 };
 
diff --git a/xen/include/public/hvm/hvm_op.h b/xen/include/public/hvm/hvm_op.h
index 6fcd86d..47e836c 100644
--- a/xen/include/public/hvm/hvm_op.h
+++ b/xen/include/public/hvm/hvm_op.h
@@ -95,22 +95,6 @@ typedef enum {
 /* Following tools-only interfaces may change in future. */
 #if defined(__XEN__) || defined(__XEN_TOOLS__)
 
-/* Track dirty VRAM. */
-#define HVMOP_track_dirty_vram    6
-struct xen_hvm_track_dirty_vram {
-    /* Domain to be tracked. */
-    domid_t  domid;
-    /* Number of pages to track. */
-    uint32_t nr;
-    /* First pfn to track. */
-    uint64_aligned_t first_pfn;
-    /* OUT variable. */
-    /* Dirty bitmap buffer. */
-    XEN_GUEST_HANDLE_64(uint8) dirty_bitmap;
-};
-typedef struct xen_hvm_track_dirty_vram xen_hvm_track_dirty_vram_t;
-DEFINE_XEN_GUEST_HANDLE(xen_hvm_track_dirty_vram_t);
-
 /* Notify that some pages got modified by the Device Model. */
 #define HVMOP_modified_memory    7
 struct xen_hvm_modified_memory {
diff --git a/xen/include/xlat.lst b/xen/include/xlat.lst
index 6b48290..55ac5fc 100644
--- a/xen/include/xlat.lst
+++ b/xen/include/xlat.lst
@@ -62,6 +62,7 @@
 ?	dm_op_get_ioreq_server_info	hvm/dm_op.h
 ?	dm_op_ioreq_server_range	hvm/dm_op.h
 ?	dm_op_set_ioreq_server_state	hvm/dm_op.h
+?	dm_op_track_dirty_vram		hvm/dm_op.h
 ?	vcpu_hvm_context		hvm/hvm_vcpu.h
 ?	vcpu_hvm_x86_32			hvm/hvm_vcpu.h
 ?	vcpu_hvm_x86_64			hvm/hvm_vcpu.h
diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
index 1ce8a36..a4272d7 100644
--- a/xen/xsm/flask/hooks.c
+++ b/xen/xsm/flask/hooks.c
@@ -1180,9 +1180,6 @@ static int flask_hvm_param(struct domain *d, unsigned long op)
     case HVMOP_get_param:
         perm = HVM__GETPARAM;
         break;
-    case HVMOP_track_dirty_vram:
-        perm = HVM__TRACKDIRTYVRAM;
-        break;
     default:
         perm = HVM__HVMCTL;
     }
diff --git a/xen/xsm/flask/policy/access_vectors b/xen/xsm/flask/policy/access_vectors
index 92e6da9..47ce589 100644
--- a/xen/xsm/flask/policy/access_vectors
+++ b/xen/xsm/flask/policy/access_vectors
@@ -268,8 +268,6 @@ class hvm
     bind_irq
 # XEN_DOMCTL_pin_mem_cacheattr
     cacheattr
-# HVMOP_track_dirty_vram
-    trackdirtyvram
 # HVMOP_modified_memory, HVMOP_get_mem_type, HVMOP_set_mem_type,
 # HVMOP_set_mem_access, HVMOP_get_mem_access, HVMOP_pagetable_dying,
 # HVMOP_inject_trap
-- 
2.1.4


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