[Xen-changelog] [xen master] kexec: implement STATUS hypercall to check if image is loaded

[patchbot@xxxxxxx]

commit 984cf6c5223d07ac10a53b25fa85356f6f98d9fb
Author:     Eric DeVolder <eric.devolder@xxxxxxxxxx>
AuthorDate: Tue Jan 17 11:29:16 2017 -0600
Commit:     Wei Liu <wei.liu2@xxxxxxxxxx>
CommitDate: Wed Jan 18 09:55:49 2017 +0000

    kexec: implement STATUS hypercall to check if image is loaded
    
    The tools that use kexec are asynchronous in nature and do not keep
    state changes. As such provide an hypercall to find out whether an
    image has been loaded for either type.
    
    Note: No need to modify XSM as it has one size fits all check and
    does not check for subcommands.
    
    Note: No need to check KEXEC_FLAG_IN_PROGRESS (and error out of
    kexec_status()) as this flag is set only once by the first/only
    cpu on the crash path.
    
    Note: This is just the Xen side of the hypercall, kexec-tools patch
    to come separately.
    
    Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
    Signed-off-by: Eric DeVolder <eric.devolder@xxxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Daniel Kiper <daniel.kiper@xxxxxxxxxx>
    Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 tools/libxc/include/xenctrl.h | 10 ++++++++++
 tools/libxc/xc_kexec.c        | 24 ++++++++++++++++++++++++
 xen/common/kexec.c            | 19 +++++++++++++++++++
 xen/include/public/kexec.h    | 13 +++++++++++++
 4 files changed, 66 insertions(+)

diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
index 4ab0f57..63c616f 100644
--- a/tools/libxc/include/xenctrl.h
+++ b/tools/libxc/include/xenctrl.h
@@ -2574,6 +2574,16 @@ int xc_kexec_load(xc_interface *xch, uint8_t type, 
uint16_t arch,
  */
 int xc_kexec_unload(xc_interface *xch, int type);
 
+/*
+ * Find out whether the image has been succesfully loaded.
+ *
+ * The type can be either KEXEC_TYPE_DEFAULT or KEXEC_TYPE_CRASH.
+ * If zero is returned, that means no image is loaded for the type.
+ * If one is returned, that means an image is loaded for the type.
+ * Otherwise, negative return value indicates error.
+ */
+int xc_kexec_status(xc_interface *xch, int type);
+
 typedef xenpf_resource_entry_t xc_resource_entry_t;
 
 /*
diff --git a/tools/libxc/xc_kexec.c b/tools/libxc/xc_kexec.c
index 59e2f07..a4e8966 100644
--- a/tools/libxc/xc_kexec.c
+++ b/tools/libxc/xc_kexec.c
@@ -126,3 +126,27 @@ out:
 
     return ret;
 }
+
+int xc_kexec_status(xc_interface *xch, int type)
+{
+    DECLARE_HYPERCALL_BUFFER(xen_kexec_status_t, status);
+    int ret = -1;
+
+    status = xc_hypercall_buffer_alloc(xch, status, sizeof(*status));
+    if ( status == NULL )
+    {
+        PERROR("Could not alloc buffer for kexec status hypercall");
+        goto out;
+    }
+
+    status->type = type;
+
+    ret = xencall2(xch->xcall, __HYPERVISOR_kexec_op,
+                   KEXEC_CMD_kexec_status,
+                   HYPERCALL_BUFFER_AS_ARG(status));
+
+out:
+    xc_hypercall_buffer_free(xch, status);
+
+    return ret;
+}
diff --git a/xen/common/kexec.c b/xen/common/kexec.c
index c83d48f..aa808cb 100644
--- a/xen/common/kexec.c
+++ b/xen/common/kexec.c
@@ -1169,6 +1169,22 @@ static int kexec_unload(XEN_GUEST_HANDLE_PARAM(void) 
uarg)
     return kexec_do_unload(&unload);
 }
 
+static int kexec_status(XEN_GUEST_HANDLE_PARAM(void) uarg)
+{
+    xen_kexec_status_t status;
+    int base, bit;
+
+    if ( unlikely(copy_from_guest(&status, uarg, 1)) )
+        return -EFAULT;
+
+    /* No need to check KEXEC_FLAG_IN_PROGRESS. */
+
+    if ( kexec_load_get_bits(status.type, &base, &bit) )
+        return -EINVAL;
+
+    return test_bit(bit, &kexec_flags);
+}
+
 static int do_kexec_op_internal(unsigned long op,
                                 XEN_GUEST_HANDLE_PARAM(void) uarg,
                                 bool_t compat)
@@ -1208,6 +1224,9 @@ static int do_kexec_op_internal(unsigned long op,
     case KEXEC_CMD_kexec_unload:
         ret = kexec_unload(uarg);
         break;
+    case KEXEC_CMD_kexec_status:
+        ret = kexec_status(uarg);
+        break;
     }
 
     return ret;
diff --git a/xen/include/public/kexec.h b/xen/include/public/kexec.h
index a6a0a88..c200e8c 100644
--- a/xen/include/public/kexec.h
+++ b/xen/include/public/kexec.h
@@ -227,6 +227,19 @@ typedef struct xen_kexec_unload {
 } xen_kexec_unload_t;
 DEFINE_XEN_GUEST_HANDLE(xen_kexec_unload_t);
 
+/*
+ * Figure out whether we have an image loaded. A return value of
+ * zero indicates no image loaded. A return value of one
+ * indicates an image is loaded. A negative return value
+ * indicates an error.
+ *
+ * Type must be one of KEXEC_TYPE_DEFAULT or KEXEC_TYPE_CRASH.
+ */
+#define KEXEC_CMD_kexec_status 6
+typedef struct xen_kexec_status {
+    uint8_t type;
+} xen_kexec_status_t;
+DEFINE_XEN_GUEST_HANDLE(xen_kexec_status_t);
 #else /* __XEN_INTERFACE_VERSION__ < 0x00040400 */
 
 #define KEXEC_CMD_kexec_load KEXEC_CMD_kexec_load_v1
--
generated by git-patchbot for /home/xen/git/xen.git#master

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