[PATCH v5 3/3] x86/altp2m: Add a hvmop for querying the suppress #VE bit

[Adrian Pop <apop@bitdefender.com>]

Signed-off-by: Adrian Pop <apop@bitdefender.com>
---
 tools/libxc/include/xenctrl.h   |  2 ++
 tools/libxc/xc_altp2m.c         | 26 +++++++++++++++++++
 xen/arch/x86/hvm/hvm.c          | 19 ++++++++++++++
 xen/arch/x86/mm/mem_access.c    | 45 +++++++++++++++++++++++++++++++++
 xen/include/public/hvm/hvm_op.h |  2 ++
 xen/include/xen/mem_access.h    |  3 +++
 6 files changed, 97 insertions(+)

diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
index cc8b3e7dce..59955f0357 100644
--- a/tools/libxc/include/xenctrl.h
+++ b/tools/libxc/include/xenctrl.h
@@ -1954,6 +1954,8 @@ 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_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,
                              uint16_t view_id, xen_pfn_t gfn,
                              xenmem_access_t access);
diff --git a/tools/libxc/xc_altp2m.c b/tools/libxc/xc_altp2m.c
index f883d0b392..1c9b572e2b 100644
--- a/tools/libxc/xc_altp2m.c
+++ b/tools/libxc/xc_altp2m.c
@@ -163,6 +163,32 @@ int xc_altp2m_switch_to_view(xc_interface *handle, uint32_t domid,
     return rc;
 }
 
+int xc_altp2m_get_suppress_ve(xc_interface *handle, uint32_t domid,
+                              uint16_t view_id, xen_pfn_t gfn, 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_get_suppress_ve;
+    arg->domain = domid;
+    arg->u.suppress_ve.view = view_id;
+    arg->u.suppress_ve.gfn = gfn;
+
+    rc = xencall2(handle->xcall, __HYPERVISOR_hvm_op, HVMOP_altp2m,
+                  HYPERCALL_BUFFER_AS_ARG(arg));
+
+    if ( !rc )
+        *sve = arg->u.suppress_ve.suppress_ve;
+
+    xc_hypercall_buffer_free(handle, arg);
+    return rc;
+}
+
 int xc_altp2m_set_suppress_ve(xc_interface *handle, uint32_t domid,
                               uint16_t view_id, xen_pfn_t gfn, bool sve)
 {
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 64ab36ff53..6f6efb0d8a 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -4525,6 +4525,7 @@ static int do_altp2m_op(
     case HVMOP_altp2m_destroy_p2m:
     case HVMOP_altp2m_switch_p2m:
     case HVMOP_altp2m_set_suppress_ve:
+    case HVMOP_altp2m_get_suppress_ve:
     case HVMOP_altp2m_set_mem_access:
     case HVMOP_altp2m_set_mem_access_multi:
     case HVMOP_altp2m_change_gfn:
@@ -4655,6 +4656,24 @@ static int do_altp2m_op(
         }
         break;
 
+    case HVMOP_altp2m_get_suppress_ve:
+        if ( a.u.suppress_ve.pad1 || a.u.suppress_ve.pad2 )
+            rc = -EINVAL;
+        else
+        {
+            gfn_t gfn = _gfn(a.u.suppress_ve.gfn);
+            unsigned int altp2m_idx = a.u.suppress_ve.view;
+            bool suppress_ve;
+
+            rc = p2m_get_suppress_ve(d, gfn, &suppress_ve, altp2m_idx);
+            if ( !rc )
+            {
+                a.u.suppress_ve.suppress_ve = suppress_ve;
+                rc = __copy_to_guest(arg, &a, 1) ? -EFAULT : 0;
+            }
+        }
+        break;
+
     case HVMOP_altp2m_set_mem_access:
         if ( a.u.set_mem_access.pad )
             rc = -EINVAL;
diff --git a/xen/arch/x86/mm/mem_access.c b/xen/arch/x86/mm/mem_access.c
index 4d49025cbe..df78c93cfd 100644
--- a/xen/arch/x86/mm/mem_access.c
+++ b/xen/arch/x86/mm/mem_access.c
@@ -550,6 +550,51 @@ out:
     return rc;
 }
 
+int p2m_get_suppress_ve(struct domain *d, gfn_t gfn, bool *suppress_ve,
+                        unsigned int altp2m_idx)
+{
+    struct p2m_domain *host_p2m = p2m_get_hostp2m(d);
+    struct p2m_domain *ap2m = NULL;
+    struct p2m_domain *p2m;
+    mfn_t mfn;
+    p2m_access_t a;
+    p2m_type_t t;
+
+    if ( !cpu_has_vmx_virt_exceptions )
+        return -EOPNOTSUPP;
+
+    /* #VE should be enabled for this vcpu. */
+    if ( gfn_eq(vcpu_altp2m(current).veinfo_gfn, INVALID_GFN) )
+        return -ENXIO;
+
+    if ( altp2m_idx > 0 )
+    {
+        if ( altp2m_idx >= MAX_ALTP2M ||
+             d->arch.altp2m_eptp[altp2m_idx] == mfn_x(INVALID_MFN) )
+            return -EINVAL;
+
+        p2m = ap2m = d->arch.altp2m_p2m[altp2m_idx];
+    }
+    else
+        p2m = host_p2m;
+
+    gfn_lock(host_p2m, gfn, 0);
+
+    if ( ap2m )
+        p2m_lock(ap2m);
+
+    mfn = p2m->get_entry(p2m, gfn, &t, &a, 0, NULL, suppress_ve);
+    if ( !mfn_valid(mfn) )
+        return -ESRCH;
+
+    if ( ap2m )
+        p2m_unlock(ap2m);
+
+    gfn_unlock(host_p2m, gfn, 0);
+
+    return 0;
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/include/public/hvm/hvm_op.h b/xen/include/public/hvm/hvm_op.h
index 14d29d1700..cf00cad164 100644
--- a/xen/include/public/hvm/hvm_op.h
+++ b/xen/include/public/hvm/hvm_op.h
@@ -306,6 +306,8 @@ struct xen_hvm_altp2m_op {
 #define HVMOP_altp2m_set_mem_access_multi 9
 /* Set the "Suppress #VE" bit on a page */
 #define HVMOP_altp2m_set_suppress_ve      10
+/* Get the "Suppress #VE" bit of a page */
+#define HVMOP_altp2m_get_suppress_ve      11
     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 a8d38b90e6..28cab673da 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_get_suppress_ve(struct domain *d, gfn_t gfn, bool *suppress_ve,
+                        unsigned int altp2m_idx);
+
 /*
  * Get access type for a gfn.
  * If gfn == INVALID_GFN, gets the default access type.
-- 
2.18.0


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