[XEN PATCH v1 1/1] x86/domctl: add gva_to_gfn command

["Ковалёв Сергей" <valor@list.ru>]

gva_to_gfn command used for fast address translation in LibVMI project.
With such a command it is possible to perform address translation in
single call instead of series of queries to get every page table.

Thanks to Dmitry Isaykin for involvement.

Signed-off-by: Sergey Kovalev <valor@list.ru>

---
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: "Roger Pau Monné" <roger.pau@citrix.com>
Cc: Wei Liu <wl@xen.org>
Cc: George Dunlap <george.dunlap@citrix.com>
Cc: Julien Grall <julien@xen.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Tamas K Lengyel <tamas@tklengyel.com>
Cc: xen-devel@lists.xenproject.org
---

---
  xen/arch/x86/domctl.c       | 17 +++++++++++++++++
  xen/include/public/domctl.h | 13 +++++++++++++
  2 files changed, 30 insertions(+)

diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index 2118fcad5d..0c9706ea0a 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -1364,6 +1364,23 @@ long arch_do_domctl(
              copyback = true;
          break;

+    case XEN_DOMCTL_gva_to_gfn:
+    {
+        uint64_t ga = domctl->u.gva_to_gfn.addr;
+        uint64_t cr3 = domctl->u.gva_to_gfn.cr3;
+        struct vcpu* v = d->vcpu[0];
+        uint32_t pfec = PFEC_page_present;
+        unsigned int page_order;
+
+        uint64_t gfn = paging_ga_to_gfn_cr3(v, cr3, ga, &pfec, 
&page_order);
+        domctl->u.gva_to_gfn.addr = gfn;
+        domctl->u.gva_to_gfn.page_order = page_order;
+        if ( __copy_to_guest(u_domctl, domctl, 1) )
+            ret = -EFAULT;
+
+        break;
+    }
+
      default:
          ret = -ENOSYS;
          break;
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 51be28c3de..628dfc68fd 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -948,6 +948,17 @@ struct xen_domctl_paging_mempool {
      uint64_aligned_t size; /* Size in bytes. */
  };

+/*
+ * XEN_DOMCTL_gva_to_gfn.
+ *
+ * Get the guest virtual to guest physicall address translated.
+ */
+struct xen_domctl_gva_to_gfn {
+    uint64_aligned_t addr;
+    uint64_aligned_t cr3;
+    uint64_aligned_t page_order;
+};
+
  #if defined(__i386__) || defined(__x86_64__)
  struct xen_domctl_vcpu_msr {
      uint32_t         index;
@@ -1278,6 +1289,7 @@ struct xen_domctl {
  #define XEN_DOMCTL_vmtrace_op                    84
  #define XEN_DOMCTL_get_paging_mempool_size       85
  #define XEN_DOMCTL_set_paging_mempool_size       86
+#define XEN_DOMCTL_gva_to_gfn                    87
  #define XEN_DOMCTL_gdbsx_guestmemio            1000
  #define XEN_DOMCTL_gdbsx_pausevcpu             1001
  #define XEN_DOMCTL_gdbsx_unpausevcpu           1002
@@ -1340,6 +1352,7 @@ struct xen_domctl {
          struct xen_domctl_vuart_op          vuart_op;
          struct xen_domctl_vmtrace_op        vmtrace_op;
          struct xen_domctl_paging_mempool    paging_mempool;
+        struct xen_domctl_gva_to_gfn        gva_to_gfn;
          uint8_t                             pad[128];
      } u;
  };
-- 
2.38.1