xen-hvm.c: Add support for Xen access to vmport

This adds synchronisation of the 6 vcpu registers (only 32bits of
them) that vmport.c needs between Xen and QEMU.

This is to avoid a 2nd and 3rd exchange between QEMU and Xen to
fetch and put these 6 vcpu registers used by the code in vmport.c
and vmmouse.c

The registers are passed in the new shared page provided by
HVM_PARAM_VMPORT_REGS_PFN.

Add new array to XenIOState that allows selection of current_cpu by
vcpu id.

Now pass XenIOState to handle_ioreq().

Add new routines regs_to_cpu(), regs_from_cpu(), and
handle_vmport_ioreq().

Signed-off-by: Don Slutz <dslutz@verizon.com>
Reviewed-by: Paul Durrant <paul.durrant@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

include/hw/xen/xen_common.h

@@ -164,4 +164,19 @@ void destroy_hvm_domain(bool reboot);
 /* shutdown/destroy current domain because of an error */
 void xen_shutdown_fatal_error(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
 
+#ifdef HVM_PARAM_VMPORT_REGS_PFN
+static inline int xen_get_vmport_regs_pfn(XenXC xc, domid_t dom,
+                                          unsigned long *vmport_regs_pfn)
+{
+    return xc_get_hvm_param(xc, dom, HVM_PARAM_VMPORT_REGS_PFN,
+                            vmport_regs_pfn);
+}
+#else
+static inline int xen_get_vmport_regs_pfn(XenXC xc, domid_t dom,
+                                          unsigned long *vmport_regs_pfn)
+{
+    return -ENOSYS;
+}
+#endif
+
 #endif /* QEMU_HW_XEN_COMMON_H */

xen-hvm.c

@@ -41,6 +41,29 @@ static MemoryRegion *framebuffer;
 static bool xen_in_migration;
 
 /* Compatibility with older version */
+
+/* This allows QEMU to build on a system that has Xen 4.5 or earlier
+ * installed.  This here (not in hw/xen/xen_common.h) because xen/hvm/ioreq.h
+ * needs to be included before this block and hw/xen/xen_common.h needs to
+ * be included before xen/hvm/ioreq.h
+ */
+#ifndef IOREQ_TYPE_VMWARE_PORT
+#define IOREQ_TYPE_VMWARE_PORT  3
+struct vmware_regs {
+    uint32_t esi;
+    uint32_t edi;
+    uint32_t ebx;
+    uint32_t ecx;
+    uint32_t edx;
+};
+typedef struct vmware_regs vmware_regs_t;
+
+struct shared_vmport_iopage {
+    struct vmware_regs vcpu_vmport_regs[1];
+};
+typedef struct shared_vmport_iopage shared_vmport_iopage_t;
+#endif
+
 #if __XEN_LATEST_INTERFACE_VERSION__ < 0x0003020a
 static inline uint32_t xen_vcpu_eport(shared_iopage_t *shared_page, int i)
 {
@@ -79,8 +102,10 @@ typedef struct XenPhysmap {
 
 typedef struct XenIOState {
     shared_iopage_t *shared_page;
+    shared_vmport_iopage_t *shared_vmport_page;
     buffered_iopage_t *buffered_io_page;
     QEMUTimer *buffered_io_timer;
+    CPUState **cpu_by_vcpu_id;
     /* the evtchn port for polling the notification, */
     evtchn_port_t *ioreq_local_port;
     /* evtchn local port for buffered io */
@@ -773,7 +798,50 @@ static void cpu_ioreq_move(ioreq_t *req)
     }
 }
 
-static void handle_ioreq(ioreq_t *req)
+static void regs_to_cpu(vmware_regs_t *vmport_regs, ioreq_t *req)
+{
+    X86CPU *cpu;
+    CPUX86State *env;
+
+    cpu = X86_CPU(current_cpu);
+    env = &cpu->env;
+    env->regs[R_EAX] = req->data;
+    env->regs[R_EBX] = vmport_regs->ebx;
+    env->regs[R_ECX] = vmport_regs->ecx;
+    env->regs[R_EDX] = vmport_regs->edx;
+    env->regs[R_ESI] = vmport_regs->esi;
+    env->regs[R_EDI] = vmport_regs->edi;
+}
+
+static void regs_from_cpu(vmware_regs_t *vmport_regs)
+{
+    X86CPU *cpu = X86_CPU(current_cpu);
+    CPUX86State *env = &cpu->env;
+
+    vmport_regs->ebx = env->regs[R_EBX];
+    vmport_regs->ecx = env->regs[R_ECX];
+    vmport_regs->edx = env->regs[R_EDX];
+    vmport_regs->esi = env->regs[R_ESI];
+    vmport_regs->edi = env->regs[R_EDI];
+}
+
+static void handle_vmport_ioreq(XenIOState *state, ioreq_t *req)
+{
+    vmware_regs_t *vmport_regs;
+
+    assert(state->shared_vmport_page);
+    vmport_regs =
+        &state->shared_vmport_page->vcpu_vmport_regs[state->send_vcpu];
+    QEMU_BUILD_BUG_ON(sizeof(*req) < sizeof(*vmport_regs));
+
+    current_cpu = state->cpu_by_vcpu_id[state->send_vcpu];
+    regs_to_cpu(vmport_regs, req);
+    cpu_ioreq_pio(req);
+    regs_from_cpu(vmport_regs);
+    current_cpu = NULL;
+}
+
+static void handle_ioreq(XenIOState *state, ioreq_t *req)
 {
     if (!req->data_is_ptr && (req->dir == IOREQ_WRITE) &&
             (req->size < sizeof (target_ulong))) {
@@ -787,6 +855,9 @@ static void handle_ioreq(ioreq_t *req)
         case IOREQ_TYPE_COPY:
             cpu_ioreq_move(req);
             break;
+        case IOREQ_TYPE_VMWARE_PORT:
+            handle_vmport_ioreq(state, req);
+            break;
         case IOREQ_TYPE_TIMEOFFSET:
             break;
         case IOREQ_TYPE_INVALIDATE:
@@ -828,7 +899,7 @@ static int handle_buffered_iopage(XenIOState *state)
             req.data |= ((uint64_t)buf_req->data) << 32;
         }
 
-        handle_ioreq(&req);
+        handle_ioreq(state, &req);
 
         xen_mb();
         state->buffered_io_page->read_pointer += qw ? 2 : 1;
@@ -857,14 +928,16 @@ static void cpu_handle_ioreq(void *opaque)
 
     handle_buffered_iopage(state);
     if (req) {
-        handle_ioreq(req);
+        handle_ioreq(state, req);
 
         if (req->state != STATE_IOREQ_INPROCESS) {
             fprintf(stderr, "Badness in I/O request ... not in service?!: "
                     "%x, ptr: %x, port: %"PRIx64", "
-                    "data: %"PRIx64", count: %" FMT_ioreq_size ", size: %" FMT_ioreq_size "\n",
+                    "data: %"PRIx64", count: %" FMT_ioreq_size
+                    ", size: %" FMT_ioreq_size
+                    ", type: %"FMT_ioreq_size"\n",
                     req->state, req->data_is_ptr, req->addr,
-                    req->data, req->count, req->size);
+                    req->data, req->count, req->size, req->type);
             destroy_hvm_domain(false);
             return;
         }
@@ -904,6 +977,14 @@ static void xen_main_loop_prepare(XenIOState *state)
                                                  state);
 
     if (evtchn_fd != -1) {
+        CPUState *cpu_state;
+
+        DPRINTF("%s: Init cpu_by_vcpu_id\n", __func__);
+        CPU_FOREACH(cpu_state) {
+            DPRINTF("%s: cpu_by_vcpu_id[%d]=%p\n",
+                    __func__, cpu_state->cpu_index, cpu_state);
+            state->cpu_by_vcpu_id[cpu_state->cpu_index] = cpu_state;
+        }
         qemu_set_fd_handler(evtchn_fd, cpu_handle_ioreq, NULL, state);
     }
 }
@@ -1020,6 +1101,20 @@ int xen_hvm_init(ram_addr_t *below_4g_mem_size, ram_addr_t *above_4g_mem_size,
                  errno, xen_xc);
     }
 
+    rc = xen_get_vmport_regs_pfn(xen_xc, xen_domid, &ioreq_pfn);
+    if (!rc) {
+        DPRINTF("shared vmport page at pfn %lx\n", ioreq_pfn);
+        state->shared_vmport_page =
+            xc_map_foreign_range(xen_xc, xen_domid, XC_PAGE_SIZE,
+                                 PROT_READ|PROT_WRITE, ioreq_pfn);
+        if (state->shared_vmport_page == NULL) {
+            hw_error("map shared vmport IO page returned error %d handle="
+                     XC_INTERFACE_FMT, errno, xen_xc);
+        }
+    } else if (rc != -ENOSYS) {
+        hw_error("get vmport regs pfn returned error %d, rc=%d", errno, rc);
+    }
+
     xc_get_hvm_param(xen_xc, xen_domid, HVM_PARAM_BUFIOREQ_PFN, &ioreq_pfn);
     DPRINTF("buffered io page at pfn %lx\n", ioreq_pfn);
     state->buffered_io_page = xc_map_foreign_range(xen_xc, xen_domid, XC_PAGE_SIZE,
@@ -1028,6 +1123,9 @@ int xen_hvm_init(ram_addr_t *below_4g_mem_size, ram_addr_t *above_4g_mem_size,
         hw_error("map buffered IO page returned error %d", errno);
     }
 
+    /* Note: cpus is empty at this point in init */
+    state->cpu_by_vcpu_id = g_malloc0(max_cpus * sizeof(CPUState *));
+
     state->ioreq_local_port = g_malloc0(max_cpus * sizeof (evtchn_port_t));
 
     /* FIXME: how about if we overflow the page here? */