[Xen-devel] [PATCH v16 01/10] x86: add generic resource (e.g. MSR) access hypercall

[Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx>]

Add a generic resource access hypercall for tool stack or other
components, e.g., accessing MSR, port I/O, etc.

Signed-off-by: Dongxiao Xu <dongxiao.xu@xxxxxxxxx>
Signed-off-by: Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx>
---
 xen/arch/x86/platform_hypercall.c        |   90 ++++++++++++++++++++++++++++++
 xen/arch/x86/x86_64/platform_hypercall.c |    4 ++
 xen/include/public/platform.h            |   23 ++++++++
 xen/include/xlat.lst                     |    2 +
 4 files changed, 119 insertions(+)

diff --git a/xen/arch/x86/platform_hypercall.c 
b/xen/arch/x86/platform_hypercall.c
index 2162811..081d9f5 100644
--- a/xen/arch/x86/platform_hypercall.c
+++ b/xen/arch/x86/platform_hypercall.c
@@ -61,6 +61,68 @@ long cpu_down_helper(void *data);
 long core_parking_helper(void *data);
 uint32_t get_cur_idle_nums(void);
 
+struct xen_resource_access {
+    int32_t ret;
+    uint32_t nr;
+    XEN_GUEST_HANDLE(xenpf_resource_data_t) data;
+};
+
+static bool_t allow_access_msr(unsigned int msr)
+{
+    return 0;
+}
+
+static void resource_access(void *info)
+{
+    struct xen_resource_access *ra = info;
+    xenpf_resource_data_t data;
+    int ret = 0;
+    unsigned int i;
+
+    for ( i = 0; i < ra->nr; i++ )
+    {
+        if ( copy_from_guest_offset(&data, ra->data, i, 1) )
+        {
+            ret = -EFAULT;
+            break;
+        }
+
+        if ( data.rsvd ) {
+            ret = -EINVAL;
+            break;
+        }
+
+        switch ( data.cmd )
+        {
+        case XEN_RESOURCE_OP_MSR_READ:
+        case XEN_RESOURCE_OP_MSR_WRITE:
+            if ( data.idx >> 32 )
+                ret = -EINVAL;
+            else if ( !allow_access_msr(data.idx) )
+                ret = -EACCES;
+            else if ( data.cmd == XEN_RESOURCE_OP_MSR_READ )
+                ret = rdmsr_safe(data.idx, data.val);
+            else
+                ret = wrmsr_safe(data.idx, data.val);
+            break;
+        default:
+            ret = -EINVAL;
+            break;
+        }
+
+        if ( ret )
+            break;
+
+        if ( copy_to_guest_offset(ra->data, i, &data, 1) )
+        {
+            ret = -EFAULT;
+            break;
+        }
+    }
+
+    ra->ret = ret;
+}
+
 ret_t do_platform_op(XEN_GUEST_HANDLE_PARAM(xen_platform_op_t) u_xenpf_op)
 {
     ret_t ret = 0;
@@ -601,6 +663,34 @@ ret_t 
do_platform_op(XEN_GUEST_HANDLE_PARAM(xen_platform_op_t) u_xenpf_op)
     }
     break;
 
+    case XENPF_resource_op:
+    {
+        struct xen_resource_access ra;
+        struct xenpf_resource_op *rsc_op = &op->u.resource_op;
+        unsigned int cpu = smp_processor_id();
+
+        ra.nr = rsc_op->nr;
+        ra.data = rsc_op->data;
+
+        if ( rsc_op->cpu == cpu )
+            resource_access(&ra);
+        else if ( cpu_online(rsc_op->cpu) )
+            on_selected_cpus(cpumask_of(rsc_op->cpu),
+                         resource_access, &ra, 1);
+        else
+        {
+            ret = -ENODEV;
+            break;
+        }
+
+        if ( ra.ret )
+        {
+            ret = ra.ret;
+            break;
+        }
+    }
+    break;
+
     default:
         ret = -ENOSYS;
         break;
diff --git a/xen/arch/x86/x86_64/platform_hypercall.c 
b/xen/arch/x86/x86_64/platform_hypercall.c
index b6f380e..4db6622 100644
--- a/xen/arch/x86/x86_64/platform_hypercall.c
+++ b/xen/arch/x86/x86_64/platform_hypercall.c
@@ -32,6 +32,10 @@ CHECK_pf_pcpu_version;
 CHECK_pf_enter_acpi_sleep;
 #undef xen_pf_enter_acpi_sleep
 
+#define xen_pf_resource_data xenpf_resource_data
+CHECK_pf_resource_data;
+#undef xen_pf_resource_data
+
 #define COMPAT
 #define _XEN_GUEST_HANDLE(t) XEN_GUEST_HANDLE(t)
 #define _XEN_GUEST_HANDLE_PARAM(t) XEN_GUEST_HANDLE_PARAM(t)
diff --git a/xen/include/public/platform.h b/xen/include/public/platform.h
index 053b9fa..e4d9091 100644
--- a/xen/include/public/platform.h
+++ b/xen/include/public/platform.h
@@ -527,6 +527,28 @@ struct xenpf_core_parking {
 typedef struct xenpf_core_parking xenpf_core_parking_t;
 DEFINE_XEN_GUEST_HANDLE(xenpf_core_parking_t);
 
+#define XENPF_resource_op   61
+
+#define XEN_RESOURCE_OP_MSR_READ  0
+#define XEN_RESOURCE_OP_MSR_WRITE 1
+
+struct xenpf_resource_data {
+    uint32_t cmd;       /* XEN_RESOURCE_OP_* */
+    uint32_t rsvd;
+    uint64_t idx;
+    uint64_t val;
+};
+typedef struct xenpf_resource_data xenpf_resource_data_t;
+DEFINE_XEN_GUEST_HANDLE(xenpf_resource_data_t);
+
+struct xenpf_resource_op {
+    uint32_t nr;    /* number of data entry */
+    uint32_t cpu;   /* which cpu to run */
+    XEN_GUEST_HANDLE(xenpf_resource_data_t) data;
+};
+typedef struct xenpf_resource_op xenpf_resource_op_t;
+DEFINE_XEN_GUEST_HANDLE(xenpf_resource_op_t);
+
 /*
  * ` enum neg_errnoval
  * ` HYPERVISOR_platform_op(const struct xen_platform_op*);
@@ -553,6 +575,7 @@ struct xen_platform_op {
         struct xenpf_cpu_hotadd        cpu_add;
         struct xenpf_mem_hotadd        mem_add;
         struct xenpf_core_parking      core_parking;
+        struct xenpf_resource_op       resource_op;
         uint8_t                        pad[128];
     } u;
 };
diff --git a/xen/include/xlat.lst b/xen/include/xlat.lst
index 9a35dd7..100fcf5 100644
--- a/xen/include/xlat.lst
+++ b/xen/include/xlat.lst
@@ -88,6 +88,8 @@
 ?      xenpf_enter_acpi_sleep          platform.h
 ?      xenpf_pcpuinfo                  platform.h
 ?      xenpf_pcpu_version              platform.h
+?      xenpf_resource_op               platform.h
+?      xenpf_resource_data             platform.h
 !      sched_poll                      sched.h
 ?      sched_remote_shutdown           sched.h
 ?      sched_shutdown                  sched.h
-- 
1.7.9.5


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