[Xen-devel] [PATCH V2 1/2] x86/altp2m: Add hypercall to set a range of sve bits

[Alexandru Stefan ISAILA <aisaila@xxxxxxxxxxxxxxx>]

By default the sve bits are not set.
This patch adds a new hypercall, xc_altp2m_set_supress_ve_multi(),
to set a range of sve bits.
The core function, p2m_set_suppress_ve_multi(), does not brake in case
of a error and it is doing a best effort for setting the bits in the
given range. A check for continuation is made in order to have
preemption on big ranges.

Signed-off-by: Alexandru Isaila <aisaila@xxxxxxxxxxxxxxx>

---
Changes since V1:
        - Remove "continue"
        - Add a new field in xen_hvm_altp2m_suppress_ve to store the
continuation value
        - Have p2m_set_suppress_ve_multi() take
xen_hvm_altp2m_suppress_ve as a param.
---
 tools/libxc/include/xenctrl.h   |  3 ++
 tools/libxc/xc_altp2m.c         | 25 ++++++++++++++
 xen/arch/x86/hvm/hvm.c          | 20 ++++++++++--
 xen/arch/x86/mm/p2m.c           | 58 +++++++++++++++++++++++++++++++++
 xen/include/public/hvm/hvm_op.h |  5 ++-
 xen/include/xen/mem_access.h    |  3 ++
 6 files changed, 111 insertions(+), 3 deletions(-)

diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
index f4431687b3..21b644f459 100644
--- a/tools/libxc/include/xenctrl.h
+++ b/tools/libxc/include/xenctrl.h
@@ -1923,6 +1923,9 @@ int xc_altp2m_switch_to_view(xc_interface *handle, 
uint32_t domid,
                              uint16_t view_id);
 int xc_altp2m_set_suppress_ve(xc_interface *handle, uint32_t domid,
                               uint16_t view_id, xen_pfn_t gfn, bool sve);
+int xc_altp2m_set_supress_ve_multi(xc_interface *handle, uint32_t domid,
+                                   uint16_t view_id, xen_pfn_t start_gfn,
+                                   uint32_t nr, bool sve);
 int xc_altp2m_get_suppress_ve(xc_interface *handle, uint32_t domid,
                               uint16_t view_id, xen_pfn_t gfn, bool *sve);
 int xc_altp2m_set_mem_access(xc_interface *handle, uint32_t domid,
diff --git a/tools/libxc/xc_altp2m.c b/tools/libxc/xc_altp2m.c
index 09dad0355e..6605d9abbe 100644
--- a/tools/libxc/xc_altp2m.c
+++ b/tools/libxc/xc_altp2m.c
@@ -234,6 +234,31 @@ int xc_altp2m_set_suppress_ve(xc_interface *handle, 
uint32_t domid,
     return rc;
 }
 
+int xc_altp2m_set_supress_ve_multi(xc_interface *handle, uint32_t domid,
+                                   uint16_t view_id, xen_pfn_t start_gfn,
+                                   uint32_t nr, bool sve)
+{
+    int rc;
+    DECLARE_HYPERCALL_BUFFER(xen_hvm_altp2m_op_t, arg);
+
+    arg = xc_hypercall_buffer_alloc(handle, arg, sizeof(*arg));
+    if ( arg == NULL )
+        return -1;
+
+    arg->version = HVMOP_ALTP2M_INTERFACE_VERSION;
+    arg->cmd = HVMOP_altp2m_set_suppress_ve_multi;
+    arg->domain = domid;
+    arg->u.suppress_ve.view = view_id;
+    arg->u.suppress_ve.gfn = start_gfn;
+    arg->u.suppress_ve.suppress_ve = sve;
+    arg->u.suppress_ve.nr = nr;
+
+    rc = xencall2(handle->xcall, __HYPERVISOR_hvm_op, HVMOP_altp2m,
+                  HYPERCALL_BUFFER_AS_ARG(arg));
+    xc_hypercall_buffer_free(handle, arg);
+    return rc;
+}
+
 int xc_altp2m_set_mem_access(xc_interface *handle, uint32_t domid,
                              uint16_t view_id, xen_pfn_t gfn,
                              xenmem_access_t access)
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 06a7b40107..66ed8b8e3e 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -4535,6 +4535,7 @@ static int do_altp2m_op(
     case HVMOP_altp2m_destroy_p2m:
     case HVMOP_altp2m_switch_p2m:
     case HVMOP_altp2m_set_suppress_ve:
+    case HVMOP_altp2m_set_suppress_ve_multi:
     case HVMOP_altp2m_get_suppress_ve:
     case HVMOP_altp2m_set_mem_access:
     case HVMOP_altp2m_set_mem_access_multi:
@@ -4681,7 +4682,7 @@ static int do_altp2m_op(
         break;
 
     case HVMOP_altp2m_set_suppress_ve:
-        if ( a.u.suppress_ve.pad1 || a.u.suppress_ve.pad2 )
+        if ( a.u.suppress_ve.pad1 )
             rc = -EINVAL;
         else
         {
@@ -4693,8 +4694,23 @@ static int do_altp2m_op(
         }
         break;
 
+    case HVMOP_altp2m_set_suppress_ve_multi:
+        if ( a.u.suppress_ve.pad1 || !a.u.suppress_ve.nr )
+            rc = -EINVAL;
+        else
+        {
+            rc = p2m_set_suppress_ve_multi(d, &a.u.suppress_ve);
+
+            if ( rc == -ERESTART )
+                if ( __copy_field_to_guest(guest_handle_cast(arg,
+                                           xen_hvm_altp2m_op_t),
+                                           &a, u.suppress_ve.opaque) )
+                    rc = -EFAULT;
+        }
+        break;
+
     case HVMOP_altp2m_get_suppress_ve:
-        if ( a.u.suppress_ve.pad1 || a.u.suppress_ve.pad2 )
+        if ( a.u.suppress_ve.pad1 )
             rc = -EINVAL;
         else
         {
diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index e5e4349dea..9e1335065d 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -3054,6 +3054,64 @@ out:
     return rc;
 }
 
+/*
+ * Set/clear the #VE suppress bit for multiple pages.  Only available on VMX.
+ */
+int p2m_set_suppress_ve_multi(struct domain *d,
+                              struct xen_hvm_altp2m_suppress_ve* sve)
+{
+    struct p2m_domain *host_p2m = p2m_get_hostp2m(d);
+    struct p2m_domain *ap2m = NULL;
+    struct p2m_domain *p2m;
+    uint64_t start = sve->opaque ?: sve->gfn;
+    int rc = 0;
+
+    if ( sve->view > 0 )
+    {
+        if ( sve->view >= MAX_ALTP2M ||
+             d->arch.altp2m_eptp[sve->view] == mfn_x(INVALID_MFN) )
+            return -EINVAL;
+
+        p2m = ap2m = d->arch.altp2m_p2m[sve->view];
+    }
+    else
+        p2m = host_p2m;
+
+    p2m_lock(host_p2m);
+
+    if ( ap2m )
+        p2m_lock(ap2m);
+
+
+    while ( start < sve->nr )
+    {
+        p2m_access_t a;
+        p2m_type_t t;
+        mfn_t mfn;
+
+        if ( altp2m_get_effective_entry(p2m, _gfn(start), &mfn, &t, &a, 
AP2MGET_query) )
+            a = p2m->default_access;
+
+        p2m->set_entry(p2m, _gfn(start), mfn, PAGE_ORDER_4K, t, a, 
sve->suppress_ve);
+
+        /* Check for continuation if it's not the last iteration. */
+        if ( sve->nr > ++start && hypercall_preempt_check() )
+        {
+            rc = -ERESTART;
+            break;
+        }
+    }
+
+    sve->opaque = start;
+
+    if ( ap2m )
+        p2m_unlock(ap2m);
+
+    p2m_unlock(host_p2m);
+
+    return rc;
+}
+
 int p2m_get_suppress_ve(struct domain *d, gfn_t gfn, bool *suppress_ve,
                         unsigned int altp2m_idx)
 {
diff --git a/xen/include/public/hvm/hvm_op.h b/xen/include/public/hvm/hvm_op.h
index 353f8034d9..9834ce0aea 100644
--- a/xen/include/public/hvm/hvm_op.h
+++ b/xen/include/public/hvm/hvm_op.h
@@ -42,8 +42,9 @@ struct xen_hvm_altp2m_suppress_ve {
     uint16_t view;
     uint8_t suppress_ve; /* Boolean type. */
     uint8_t pad1;
-    uint32_t pad2;
+    uint32_t nr;
     uint64_t gfn;
+    uint64_t opaque;
 };
 
 #if __XEN_INTERFACE_VERSION__ < 0x00040900
@@ -339,6 +340,8 @@ struct xen_hvm_altp2m_op {
 #define HVMOP_altp2m_vcpu_disable_notify  13
 /* Get the active vcpu p2m index */
 #define HVMOP_altp2m_get_p2m_idx          14
+/* Set the "Supress #VE" bit for a range of pages */
+#define HVMOP_altp2m_set_suppress_ve_multi 15
     domid_t domain;
     uint16_t pad1;
     uint32_t pad2;
diff --git a/xen/include/xen/mem_access.h b/xen/include/xen/mem_access.h
index e4d24502e0..ffecd2650e 100644
--- a/xen/include/xen/mem_access.h
+++ b/xen/include/xen/mem_access.h
@@ -75,6 +75,9 @@ long p2m_set_mem_access_multi(struct domain *d,
 int p2m_set_suppress_ve(struct domain *d, gfn_t gfn, bool suppress_ve,
                         unsigned int altp2m_idx);
 
+int p2m_set_suppress_ve_multi(struct domain *d,
+                              struct xen_hvm_altp2m_suppress_ve* suppress_ve);
+
 int p2m_get_suppress_ve(struct domain *d, gfn_t gfn, bool *suppress_ve,
                         unsigned int altp2m_idx);
 
-- 
2.17.1


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