1200-hypercall-XENMEM_get_mfn_from_pfn.patch

From 6dea874a453d50cf064dd198679c26d22f84b527 Mon Sep 17 00:00:00 2001
From: Wei Ye <wei.ye@intel.com>
Date: Thu, 21 Aug 2014 03:45:38 +0800
Subject: [PATCH] hypercall: XENMEM_get_mfn_from_pfn

Suppose that we should find an existing method to achieve the same
goal.

Signed-off-by: Wei Ye <wei.ye@intel.com>
Signed-off-by: Yu Zhang <yu.c.zhang@intel.com>
---
 xen/arch/x86/mm.c           | 64 +++++++++++++++++++++++++++++++++++++
 xen/include/public/memory.h | 23 +++++++++++++
 2 files changed, 87 insertions(+)

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index b30453b9de11..54734371681e 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -4693,6 +4693,61 @@ static int cf_check handle_iomem_range(
     return err || s > e ? err : _handle_iomem_range(s, e, p);
 }
 
+static int get_mfn_from_pfn(XEN_GUEST_HANDLE(xen_get_mfn_from_pfn_t) arg)
+{
+    struct xen_get_mfn_from_pfn cmd_info;
+    struct domain *d;
+    int rc=0, i;
+    xen_pfn_t *pfns = NULL;
+    xen_pfn_t pfn;
+    struct p2m_domain *p2m;
+    p2m_type_t t;
+
+    if ( !is_hardware_domain(current->domain) )
+        return -EPERM;
+
+    if ( copy_from_guest(&cmd_info, arg, 1) )
+        return -EFAULT;
+
+    d = rcu_lock_domain_by_any_id(cmd_info.domid);
+    if ( d == NULL )
+        return -ESRCH;
+
+    /* sanity check for security */
+    if (cmd_info.nr_pfns > 2048 )
+        return -ENOMEM;
+
+    pfns = xmalloc_array(xen_pfn_t, cmd_info.nr_pfns);
+    if (pfns == NULL)
+        return -ENOMEM;
+
+    if (copy_from_guest(pfns, cmd_info.pfn_list, cmd_info.nr_pfns)){
+        rc = -EFAULT;
+        goto out;
+    }
+
+    p2m = p2m_get_hostp2m(d);
+    for(i=0; i < cmd_info.nr_pfns; i++){
+        pfn = pfns[i];
+        pfns[i] = mfn_x(get_gfn_query(d, pfn, &t));
+		if(pfns[i] == mfn_x(INVALID_MFN)){
+			rc = -EINVAL;
+			goto out;
+		}
+		put_gfn(d, pfn);
+    }
+
+    if (copy_to_guest(cmd_info.pfn_list, pfns, cmd_info.nr_pfns)){
+        rc = -EFAULT;
+        goto out;
+    }
+
+out:
+    rcu_unlock_domain(d);
+    xfree(pfns);
+    return rc;
+}
+
 long arch_memory_op(unsigned long cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
 {
     int rc;
@@ -4903,6 +4958,15 @@ long arch_memory_op(unsigned long cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
     }
 #endif
 
+#ifdef __x86_64__
+    case XENMEM_get_sharing_freed_pages:
+        return mem_sharing_get_nr_saved_mfns();
+#endif
+
+    case XENMEM_get_mfn_from_pfn:
+        return get_mfn_from_pfn(guest_handle_cast(arg, xen_get_mfn_from_pfn_t));
+        break;
+
     default:
         return subarch_memory_op(cmd, arg);
     }
diff --git a/xen/include/public/memory.h b/xen/include/public/memory.h
index 5e545ae9a418..c522241e141f 100644
--- a/xen/include/public/memory.h
+++ b/xen/include/public/memory.h
@@ -682,6 +682,29 @@ struct xen_mem_acquire_resource {
 typedef struct xen_mem_acquire_resource xen_mem_acquire_resource_t;
 DEFINE_XEN_GUEST_HANDLE(xen_mem_acquire_resource_t);
 
+/*
+ * Translate the given guest PFNs to MFNs
+ */
+#define XENMEM_get_mfn_from_pfn    29
+struct xen_get_mfn_from_pfn {
+    /*
+     * Pointer to buffer to fill with list of pfn.
+     * for IN, it contains the guest PFN that need to translated
+     * for OUT, it contains the translated MFN. or INVALID_MFN if no valid translation
+     */
+    XEN_GUEST_HANDLE(xen_pfn_t) pfn_list;
+
+    /*
+     * IN: Size of the pfn_array.
+     */
+    unsigned int nr_pfns;
+
+    /* IN: which domain */
+    domid_t domid;
+};
+typedef struct xen_get_mfn_from_pfn xen_get_mfn_from_pfn_t;
+DEFINE_XEN_GUEST_HANDLE(xen_get_mfn_from_pfn_t);
+
 /*
  * XENMEM_get_vnumainfo used by guest to get
  * vNUMA topology from hypervisor.
-- 
2.44.0