hw/xen: Expose handle_bufioreq in xen_register_ioreq

Expose handle_bufioreq in xen_register_ioreq().
This is to allow machines to enable or disable buffered ioreqs.

No functional change since all callers still set it to
HVM_IOREQSRV_BUFIOREQ_ATOMIC.

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@amd.com>

1 files changed, 62 insertions, 38 deletions

diff --git a/hw/xen/xen-hvm-common.c b/hw/xen/xen-hvm-common.c
index 3a9d6f981b..7d2b72853b 100644
--- a/hw/xen/xen-hvm-common.c
+++ b/hw/xen/xen-hvm-common.c
@@ -667,6 +667,8 @@ static int xen_map_ioreq_server(XenIOState *state)
     xen_pfn_t ioreq_pfn;
     xen_pfn_t bufioreq_pfn;
     evtchn_port_t bufioreq_evtchn;
+    unsigned long num_frames = 1;
+    unsigned long frame = 1;
     int rc;
 
     /*
@@ -675,59 +677,78 @@ static int xen_map_ioreq_server(XenIOState *state)
      */
     QEMU_BUILD_BUG_ON(XENMEM_resource_ioreq_server_frame_bufioreq != 0);
     QEMU_BUILD_BUG_ON(XENMEM_resource_ioreq_server_frame_ioreq(0) != 1);
+
+    if (state->has_bufioreq) {
+        frame = 0;
+        num_frames = 2;
+    }
     state->fres = xenforeignmemory_map_resource(xen_fmem, xen_domid,
                                          XENMEM_resource_ioreq_server,
-                                         state->ioservid, 0, 2,
+                                         state->ioservid,
+                                         frame, num_frames,
                                          &addr,
                                          PROT_READ | PROT_WRITE, 0);
     if (state->fres != NULL) {
         trace_xen_map_resource_ioreq(state->ioservid, addr);
-        state->buffered_io_page = addr;
-        state->shared_page = addr + XC_PAGE_SIZE;
+        state->shared_page = addr;
+        if (state->has_bufioreq) {
+            state->buffered_io_page = addr;
+            state->shared_page = addr + XC_PAGE_SIZE;
+        }
     } else if (errno != EOPNOTSUPP) {
         error_report("failed to map ioreq server resources: error %d handle=%p",
                      errno, xen_xc);
         return -1;
     }
 
-    rc = xen_get_ioreq_server_info(xen_domid, state->ioservid,
-                                   (state->shared_page == NULL) ?
-                                   &ioreq_pfn : NULL,
-                                   (state->buffered_io_page == NULL) ?
-                                   &bufioreq_pfn : NULL,
-                                   &bufioreq_evtchn);
-    if (rc < 0) {
-        error_report("failed to get ioreq server info: error %d handle=%p",
-                     errno, xen_xc);
-        return rc;
-    }
+    /*
+     * If we fail to map the shared page with xenforeignmemory_map_resource()
+     * or if we're using buffered ioreqs, we need xen_get_ioreq_server_info()
+     * to provide the the addresses to map the shared page and/or to get the
+     * event-channel port for buffered ioreqs.
+     */
+    if (state->shared_page == NULL || state->has_bufioreq) {
+        rc = xen_get_ioreq_server_info(xen_domid, state->ioservid,
+                                       (state->shared_page == NULL) ?
+                                       &ioreq_pfn : NULL,
+                                       (state->has_bufioreq &&
+                                        state->buffered_io_page == NULL) ?
+                                       &bufioreq_pfn : NULL,
+                                       &bufioreq_evtchn);
+        if (rc < 0) {
+            error_report("failed to get ioreq server info: error %d handle=%p",
+                         errno, xen_xc);
+            return rc;
+        }
 
-    if (state->shared_page == NULL) {
-        trace_xen_map_ioreq_server_shared_page(ioreq_pfn);
+        if (state->shared_page == NULL) {
+            trace_xen_map_ioreq_server_shared_page(ioreq_pfn);
 
-        state->shared_page = xenforeignmemory_map(xen_fmem, xen_domid,
-                                                  PROT_READ | PROT_WRITE,
-                                                  1, &ioreq_pfn, NULL);
+            state->shared_page = xenforeignmemory_map(xen_fmem, xen_domid,
+                                                      PROT_READ | PROT_WRITE,
+                                                      1, &ioreq_pfn, NULL);
+        }
         if (state->shared_page == NULL) {
             error_report("map shared IO page returned error %d handle=%p",
                          errno, xen_xc);
         }
-    }
 
-    if (state->buffered_io_page == NULL) {
-        trace_xen_map_ioreq_server_buffered_io_page(bufioreq_pfn);
+        if (state->has_bufioreq && state->buffered_io_page == NULL) {
+            trace_xen_map_ioreq_server_buffered_io_page(bufioreq_pfn);
 
-        state->buffered_io_page = xenforeignmemory_map(xen_fmem, xen_domid,
-                                                       PROT_READ | PROT_WRITE,
-                                                       1, &bufioreq_pfn,
-                                                       NULL);
-        if (state->buffered_io_page == NULL) {
-            error_report("map buffered IO page returned error %d", errno);
-            return -1;
+            state->buffered_io_page = xenforeignmemory_map(xen_fmem, xen_domid,
+                                                        PROT_READ | PROT_WRITE,
+                                                        1, &bufioreq_pfn,
+                                                        NULL);
+            if (state->buffered_io_page == NULL) {
+                error_report("map buffered IO page returned error %d", errno);
+                return -1;
+            }
         }
     }
 
-    if (state->shared_page == NULL || state->buffered_io_page == NULL) {
+    if (state->shared_page == NULL ||
+        (state->has_bufioreq && state->buffered_io_page == NULL)) {
         return -1;
     }
 
@@ -830,14 +851,15 @@ static void xen_do_ioreq_register(XenIOState *state,
         state->ioreq_local_port[i] = rc;
     }
 
-    rc = qemu_xen_evtchn_bind_interdomain(state->xce_handle, xen_domid,
-                                          state->bufioreq_remote_port);
-    if (rc == -1) {
-        error_report("buffered evtchn bind error %d", errno);
-        goto err;
+    if (state->has_bufioreq) {
+        rc = qemu_xen_evtchn_bind_interdomain(state->xce_handle, xen_domid,
+                                              state->bufioreq_remote_port);
+        if (rc == -1) {
+            error_report("buffered evtchn bind error %d", errno);
+            goto err;
+        }
+        state->bufioreq_local_port = rc;
     }
-    state->bufioreq_local_port = rc;
-
     /* Init RAM management */
 #ifdef XEN_COMPAT_PHYSMAP
     xen_map_cache_init(xen_phys_offset_to_gaddr, state);
@@ -865,6 +887,7 @@ err:
 }
 
 void xen_register_ioreq(XenIOState *state, unsigned int max_cpus,
+                        uint8_t handle_bufioreq,
                         const MemoryListener *xen_memory_listener)
 {
     int rc;
@@ -883,7 +906,8 @@ void xen_register_ioreq(XenIOState *state, unsigned int max_cpus,
         goto err;
     }
 
-    rc = xen_create_ioreq_server(xen_domid, &state->ioservid);
+    state->has_bufioreq = handle_bufioreq != HVM_IOREQSRV_BUFIOREQ_OFF;
+    rc = xen_create_ioreq_server(xen_domid, handle_bufioreq, &state->ioservid);
     if (!rc) {
         xen_do_ioreq_register(state, max_cpus, xen_memory_listener);
     } else {