[Xen-devel] [RFC 2/3] x86/altp2m: Add a hvmop for setting the suppress #VE bit

[Adrian Pop <apop@xxxxxxxxxxxxxxx>]

Introduce a new hvmop, HVMOP_altp2m_set_suppress_ve, which allows a
domain to change the value of the #VE suppress bit for a page.

Signed-off-by: Adrian Pop <apop@xxxxxxxxxxxxxxx>
---
 xen/arch/x86/hvm/hvm.c          | 14 ++++++++++++
 xen/arch/x86/mm/mem_access.c    | 48 +++++++++++++++++++++++++++++++++++++++++
 xen/include/public/hvm/hvm_op.h | 15 +++++++++++++
 xen/include/xen/mem_access.h    |  3 +++
 4 files changed, 80 insertions(+)

diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 2e76c2345b..eb01527c5b 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -4356,6 +4356,7 @@ 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_suppress_ve:
     case HVMOP_altp2m_change_gfn:
         break;
     default:
@@ -4472,6 +4473,19 @@ static int do_altp2m_op(
                                     a.u.set_mem_access.view);
         break;
 
+    case HVMOP_altp2m_set_suppress_ve:
+        if ( a.u.set_suppress_ve.pad1 || a.u.set_suppress_ve.pad2 )
+            rc = -EINVAL;
+        else
+        {
+            gfn_t gfn = _gfn(a.u.set_mem_access.gfn);
+            unsigned int altp2m_idx = a.u.set_mem_access.view;
+            uint8_t suppress_ve = a.u.set_suppress_ve.suppress_ve;
+
+            rc = p2m_set_suppress_ve(d, gfn, suppress_ve, altp2m_idx);
+        }
+        break;
+
     case HVMOP_altp2m_change_gfn:
         if ( a.u.change_gfn.pad1 || a.u.change_gfn.pad2 )
             rc = -EINVAL;
diff --git a/xen/arch/x86/mm/mem_access.c b/xen/arch/x86/mm/mem_access.c
index d0b0767855..b9e611d3db 100644
--- a/xen/arch/x86/mm/mem_access.c
+++ b/xen/arch/x86/mm/mem_access.c
@@ -466,6 +466,54 @@ int p2m_get_mem_access(struct domain *d, gfn_t gfn, 
xenmem_access_t *access)
 }
 
 /*
+ * Set/clear the #VE suppress bit for a page.  Only available on VMX.
+ */
+int p2m_set_suppress_ve(struct domain *d, gfn_t gfn, uint8_t suppress_ve,
+                        unsigned int altp2m_idx)
+{
+    struct p2m_domain *host_p2m = p2m_get_hostp2m(d);
+    struct p2m_domain *ap2m = NULL;
+    struct p2m_domain *p2m = NULL;
+    mfn_t mfn;
+    p2m_access_t a;
+    p2m_type_t t;
+    unsigned long gfn_l;
+    int rc = 0;
+
+    if ( !cpu_has_vmx )
+        return -EOPNOTSUPP;
+
+    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;
+    }
+
+    p2m_lock(host_p2m);
+    if ( ap2m )
+        p2m_lock(ap2m);
+
+    gfn_l = gfn_x(gfn);
+    mfn = p2m->get_entry(p2m, gfn_l, &t, &a, 0, NULL, NULL);
+    if ( !mfn_valid(mfn) )
+        return -ESRCH;
+    rc = p2m->set_entry(p2m, gfn_l, mfn, PAGE_ORDER_4K, t, a,
+                        suppress_ve);
+    if ( ap2m )
+        p2m_unlock(ap2m);
+    p2m_unlock(host_p2m);
+
+    return rc;
+}
+
+/*
  * Local variables:
  * mode: C
  * c-file-style: "BSD"
diff --git a/xen/include/public/hvm/hvm_op.h b/xen/include/public/hvm/hvm_op.h
index bc00ef0e65..9736092f58 100644
--- a/xen/include/public/hvm/hvm_op.h
+++ b/xen/include/public/hvm/hvm_op.h
@@ -231,6 +231,18 @@ 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_suppress_ve {
+    /* view */
+    uint16_t view;
+    uint8_t suppress_ve;
+    uint8_t pad1;
+    uint32_t pad2;
+    /* gfn */
+    uint64_t gfn;
+};
+typedef struct xen_hvm_altp2m_set_suppress_ve xen_hvm_altp2m_set_suppress_ve_t;
+DEFINE_XEN_GUEST_HANDLE(xen_hvm_altp2m_set_suppress_ve_t);
+
 struct xen_hvm_altp2m_change_gfn {
     /* view */
     uint16_t view;
@@ -262,6 +274,8 @@ 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 the "Suppress #VE" bit on a page */
+#define HVMOP_altp2m_set_suppress_ve      9
     domid_t domain;
     uint16_t pad1;
     uint32_t pad2;
@@ -270,6 +284,7 @@ struct xen_hvm_altp2m_op {
         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_set_suppress_ve    set_suppress_ve;
         struct xen_hvm_altp2m_change_gfn         change_gfn;
         uint8_t pad[64];
     } u;
diff --git a/xen/include/xen/mem_access.h b/xen/include/xen/mem_access.h
index 5ab34c1553..b6e6a7650a 100644
--- a/xen/include/xen/mem_access.h
+++ b/xen/include/xen/mem_access.h
@@ -78,6 +78,9 @@ long p2m_set_mem_access_multi(struct domain *d,
  */
 int p2m_get_mem_access(struct domain *d, gfn_t gfn, xenmem_access_t *access);
 
+int p2m_set_suppress_ve(struct domain *d, gfn_t gfn, uint8_t suppress_ve,
+                        unsigned int altp2m_idx);
+
 #ifdef CONFIG_HAS_MEM_ACCESS
 int mem_access_memop(unsigned long cmd,
                      XEN_GUEST_HANDLE_PARAM(xen_mem_access_op_t) arg);
-- 
2.12.1


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