[Xen-devel] [PATCH V2] x86/altp2m: Added xc_altp2m_set_mem_access_multi()

[Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>]

For the default EPT view we have xc_set_mem_access_multi(), which
is able to set an array of pages to an array of access rights with
a single hypercall. However, this functionality was lacking for the
altp2m subsystem, which could only set page restrictions for one
page at a time. This patch addresses the gap.

Signed-off-by: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>

---
Changes since V1:
 - Replaced the mask-based hypercall continuation code with code
   using an opaque member to store the index.
---
 tools/libxc/include/xenctrl.h   |  3 +++
 tools/libxc/xc_altp2m.c         | 41 +++++++++++++++++++++++++++++++++++++++++
 xen/arch/x86/hvm/hvm.c          | 25 +++++++++++++++++++++++++
 xen/include/public/hvm/hvm_op.h | 30 +++++++++++++++++++++++++-----
 4 files changed, 94 insertions(+), 5 deletions(-)

diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
index a48981a..645b5bd 100644
--- a/tools/libxc/include/xenctrl.h
+++ b/tools/libxc/include/xenctrl.h
@@ -1903,6 +1903,9 @@ int xc_altp2m_switch_to_view(xc_interface *handle, 
domid_t domid,
 int xc_altp2m_set_mem_access(xc_interface *handle, domid_t domid,
                              uint16_t view_id, xen_pfn_t gfn,
                              xenmem_access_t access);
+int xc_altp2m_set_mem_access_multi(xc_interface *handle, domid_t domid,
+                                   uint16_t view_id, uint8_t *access,
+                                   uint64_t *pages, uint32_t nr);
 int xc_altp2m_change_gfn(xc_interface *handle, domid_t domid,
                          uint16_t view_id, xen_pfn_t old_gfn,
                          xen_pfn_t new_gfn);
diff --git a/tools/libxc/xc_altp2m.c b/tools/libxc/xc_altp2m.c
index 0639632..f202ca1 100644
--- a/tools/libxc/xc_altp2m.c
+++ b/tools/libxc/xc_altp2m.c
@@ -188,6 +188,47 @@ int xc_altp2m_set_mem_access(xc_interface *handle, domid_t 
domid,
     return rc;
 }
 
+int xc_altp2m_set_mem_access_multi(xc_interface *xch, domid_t domid,
+                                   uint16_t view_id, uint8_t *access,
+                                   uint64_t *pages, uint32_t nr)
+{
+    int rc;
+
+    DECLARE_HYPERCALL_BUFFER(xen_hvm_altp2m_op_t, arg);
+    DECLARE_HYPERCALL_BOUNCE(access, nr, XC_HYPERCALL_BUFFER_BOUNCE_IN);
+    DECLARE_HYPERCALL_BOUNCE(pages, nr * sizeof(uint64_t),
+                             XC_HYPERCALL_BUFFER_BOUNCE_IN);
+
+    arg = xc_hypercall_buffer_alloc(xch, arg, sizeof(*arg));
+    if ( arg == NULL )
+        return -1;
+
+    arg->version = HVMOP_ALTP2M_INTERFACE_VERSION;
+    arg->cmd = HVMOP_altp2m_set_mem_access_multi;
+    arg->domain = domid;
+    arg->u.set_mem_access_multi.view = view_id;
+    arg->u.set_mem_access_multi.nr = nr;
+
+    if ( xc_hypercall_bounce_pre(xch, pages) ||
+         xc_hypercall_bounce_pre(xch, access) )
+    {
+        PERROR("Could not bounce memory for 
HVMOP_altp2m_set_mem_access_multi");
+        return -1;
+    }
+
+    set_xen_guest_handle(arg->u.set_mem_access_multi.pfn_list, pages);
+    set_xen_guest_handle(arg->u.set_mem_access_multi.access_list, access);
+
+    rc = xencall2(xch->xcall, __HYPERVISOR_hvm_op, HVMOP_altp2m,
+                 HYPERCALL_BUFFER_AS_ARG(arg));
+
+    xc_hypercall_buffer_free(xch, arg);
+    xc_hypercall_bounce_post(xch, access);
+    xc_hypercall_bounce_post(xch, pages);
+
+    return rc;
+}
+
 int xc_altp2m_change_gfn(xc_interface *handle, domid_t domid,
                          uint16_t view_id, xen_pfn_t old_gfn,
                          xen_pfn_t new_gfn)
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index ccfae4f..12b34da 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -4419,6 +4419,7 @@ static int do_altp2m_op(
     case HVMOP_altp2m_destroy_p2m:
     case HVMOP_altp2m_switch_p2m:
     case HVMOP_altp2m_set_mem_access:
+    case HVMOP_altp2m_set_mem_access_multi:
     case HVMOP_altp2m_change_gfn:
         break;
     default:
@@ -4535,6 +4536,30 @@ static int do_altp2m_op(
                                     a.u.set_mem_access.view);
         break;
 
+    case HVMOP_altp2m_set_mem_access_multi:
+        if ( a.u.set_mem_access_multi.pad ||
+             a.u.set_mem_access_multi.opaque >= a.u.set_mem_access_multi.nr )
+        {
+            rc = -EINVAL;
+            break;
+        }
+        rc = p2m_set_mem_access_multi(d, a.u.set_mem_access_multi.pfn_list,
+                                      a.u.set_mem_access_multi.access_list,
+                                      a.u.set_mem_access_multi.nr,
+                                      a.u.set_mem_access_multi.opaque,
+                                      MEMOP_CMD_MASK,
+                                      a.u.set_mem_access_multi.view);
+        if ( rc > 0 )
+        {
+            a.u.set_mem_access_multi.opaque = rc;
+            if ( __copy_to_guest(arg, &a, 1) )
+                rc = -EFAULT;
+            else
+                rc = hypercall_create_continuation(__HYPERVISOR_hvm_op, "lh",
+                                                   HVMOP_altp2m, arg);
+        }
+        break;
+
     case HVMOP_altp2m_change_gfn:
         if ( a.u.change_gfn.pad1 || a.u.change_gfn.pad2 )
             rc = -EINVAL;
diff --git a/xen/include/public/hvm/hvm_op.h b/xen/include/public/hvm/hvm_op.h
index bc00ef0..f2429f8 100644
--- a/xen/include/public/hvm/hvm_op.h
+++ b/xen/include/public/hvm/hvm_op.h
@@ -231,6 +231,23 @@ struct xen_hvm_altp2m_set_mem_access {
 typedef struct xen_hvm_altp2m_set_mem_access xen_hvm_altp2m_set_mem_access_t;
 DEFINE_XEN_GUEST_HANDLE(xen_hvm_altp2m_set_mem_access_t);
 
+struct xen_hvm_altp2m_set_mem_access_multi {
+    /* view */
+    uint16_t view;
+    uint16_t pad;
+    /* Number of pages */
+    uint32_t nr;
+    /* Used for continuation purposes */
+    uint64_t opaque;
+    /* List of pfns to set access for */
+    XEN_GUEST_HANDLE(const_uint64) pfn_list;
+    /* Corresponding list of access settings for pfn_list */
+    XEN_GUEST_HANDLE(const_uint8) access_list;
+};
+typedef struct xen_hvm_altp2m_set_mem_access_multi
+    xen_hvm_altp2m_set_mem_access_multi_t;
+DEFINE_XEN_GUEST_HANDLE(xen_hvm_altp2m_set_mem_access_multi_t);
+
 struct xen_hvm_altp2m_change_gfn {
     /* view */
     uint16_t view;
@@ -262,15 +279,18 @@ struct xen_hvm_altp2m_op {
 #define HVMOP_altp2m_set_mem_access       7
 /* Change a p2m entry to have a different gfn->mfn mapping */
 #define HVMOP_altp2m_change_gfn           8
+/* Set access for an array of pages */
+#define HVMOP_altp2m_set_mem_access_multi 9
     domid_t domain;
     uint16_t pad1;
     uint32_t pad2;
     union {
-        struct xen_hvm_altp2m_domain_state       domain_state;
-        struct xen_hvm_altp2m_vcpu_enable_notify enable_notify;
-        struct xen_hvm_altp2m_view               view;
-        struct xen_hvm_altp2m_set_mem_access     set_mem_access;
-        struct xen_hvm_altp2m_change_gfn         change_gfn;
+        struct xen_hvm_altp2m_domain_state         domain_state;
+        struct xen_hvm_altp2m_vcpu_enable_notify   enable_notify;
+        struct xen_hvm_altp2m_view                 view;
+        struct xen_hvm_altp2m_set_mem_access       set_mem_access;
+        struct xen_hvm_altp2m_change_gfn           change_gfn;
+        struct xen_hvm_altp2m_set_mem_access_multi set_mem_access_multi;
         uint8_t pad[64];
     } u;
 };
-- 
1.9.1


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