[Qemu-devel] [PATCH v2 1/1] xen-hvm.c: Add support for Xen access to vmport

[Don Slutz]

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

Add new array to XenIOState that allows selection of current_cpu by
ioreq_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 <address@hidden>
---
v2:
   More info in commit message.
       Added vmware_ioreq_t
      Added cpu_by_ioreq_id.
      Set current_cpu in regs_to_cpu(), clear in regs_from_cpu().
      Drop all changes to vmport.c

 xen-hvm.c | 152 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 137 insertions(+), 15 deletions(-)

diff --git a/xen-hvm.c b/xen-hvm.c
index 05e522c..d80f21c 100644
--- a/xen-hvm.c
+++ b/xen-hvm.c
@@ -41,6 +41,31 @@ 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_ioreq {
+        uint32_t esi;
+        uint32_t edi;
+        uint32_t eax;
+        uint32_t ebx;
+        uint32_t ecx;
+        uint32_t edx;
+        uint32_t vp_eport; /* evtchn for notifications to/from device model */
+        uint16_t addr;
+        uint8_t  state:4;
+        uint8_t  dir:1;    /* 1=read, 0=write */
+        uint8_t  size:3;
+        uint8_t  type;     /* I/O type */
+};
+typedef struct vmware_ioreq vmware_ioreq_t;
+#endif
+
 #if __XEN_LATEST_INTERFACE_VERSION__ < 0x0003020a
 static inline uint32_t xen_vcpu_eport(shared_iopage_t *shared_page, int i)
 {
@@ -81,6 +106,7 @@ typedef struct XenIOState {
     shared_iopage_t *shared_page;
     buffered_iopage_t *buffered_io_page;
     QEMUTimer *buffered_io_timer;
+    CPUState **cpu_by_ioreq_id;
     /* the evtchn port for polling the notification, */
     evtchn_port_t *ioreq_local_port;
     /* evtchn local port for buffered io */
@@ -101,6 +127,8 @@ typedef struct XenIOState {
     Notifier wakeup;
 } XenIOState;
 
+static void handle_ioreq(XenIOState *state, ioreq_t *req);
+
 /* Xen specific function for piix pci */
 
 int xen_pci_slot_get_pirq(PCIDevice *pci_dev, int irq_num)
@@ -596,11 +624,23 @@ static ioreq_t 
*cpu_get_ioreq_from_shared_memory(XenIOState *state, int vcpu)
     ioreq_t *req = xen_vcpu_ioreq(state->shared_page, vcpu);
 
     if (req->state != STATE_IOREQ_READY) {
-        DPRINTF("I/O request not ready: "
-                "%x, ptr: %x, port: %"PRIx64", "
-                "data: %"PRIx64", count: %" FMT_ioreq_size ", size: %" 
FMT_ioreq_size "\n",
-                req->state, req->data_is_ptr, req->addr,
-                req->data, req->count, req->size);
+        if (req->type != IOREQ_TYPE_VMWARE_PORT) {
+            DPRINTF("I/O request not ready: "
+                    "%x, ptr: %x, port: %"PRIx64", "
+                    "data: %"PRIx64", count: %" FMT_ioreq_size ", size: %"
+                    FMT_ioreq_size "\n",
+                    req->state, req->data_is_ptr, req->addr,
+                    req->data, req->count, req->size);
+        } else {
+#ifdef DEBUG_XEN_HVM
+            vmware_ioreq_t *vp = (vmware_ioreq_t *)req;
+            DPRINTF("I/O VMware request not ready: "
+                    "%x, ptr: 0, port: %x, data: %x"
+                    ", count: 1, size: %d\n",
+                    vp->state, (uint16_t)vp->edx, vp->eax,
+                    vp->size);
+#endif
+        }
         return NULL;
     }
 
@@ -773,10 +813,73 @@ static void cpu_ioreq_move(ioreq_t *req)
     }
 }
 
-static void handle_ioreq(ioreq_t *req)
+static void regs_to_cpu(XenIOState *state, vmware_ioreq_t *vmport_req)
+{
+    X86CPU *cpu;
+    CPUX86State *env;
+
+    if (!state->cpu_by_ioreq_id[0]) {
+        CPUState *cpu_state;
+
+        CPU_FOREACH(cpu_state) {
+            state->cpu_by_ioreq_id[cpu_state->cpu_index] = cpu_state;
+        }
+    }
+    current_cpu = state->cpu_by_ioreq_id[state->send_vcpu];
+    cpu = X86_CPU(current_cpu);
+    env = &cpu->env;
+    env->regs[R_EAX] = vmport_req->eax;
+    env->regs[R_EBX] = vmport_req->ebx;
+    env->regs[R_ECX] = vmport_req->ecx;
+    env->regs[R_EDX] = vmport_req->edx;
+    env->regs[R_ESI] = vmport_req->esi;
+    env->regs[R_EDI] = vmport_req->edi;
+}
+
+static void regs_from_cpu(XenIOState *state, vmware_ioreq_t *vmport_req,
+                          ioreq_t *req)
+{
+    X86CPU *cpu = X86_CPU(current_cpu);
+    CPUX86State *env = &cpu->env;
+
+    assert(sizeof(*vmport_req) == sizeof(*req));
+    assert(offsetof(ioreq_t, type) == offsetof(vmware_ioreq_t, type));
+    assert(offsetof(ioreq_t, vp_eport) == offsetof(vmware_ioreq_t, vp_eport));
+
+    vmport_req->eax = env->regs[R_EAX];
+    vmport_req->ebx = env->regs[R_EBX];
+    vmport_req->ecx = env->regs[R_ECX];
+    vmport_req->edx = env->regs[R_EDX];
+    vmport_req->esi = env->regs[R_ESI];
+    vmport_req->edi = env->regs[R_EDI];
+    current_cpu = NULL;
+}
+
+static void handle_vmport_ioreq(XenIOState *state, vmware_ioreq_t *vmport_req)
+{
+    ioreq_t req;
+
+    memset(&req, 0x00, sizeof(req));
+
+    req.size = vmport_req->size;
+    req.count = 1;
+    req.addr = vmport_req->addr;
+    req.data = vmport_req->eax;
+    req.state = STATE_IOREQ_READY;
+    req.dir = vmport_req->dir;
+    req.df = 0;
+    req.type = IOREQ_TYPE_PIO;
+    req.data_is_ptr = 0;
+
+    regs_to_cpu(state, vmport_req);
+    handle_ioreq(state, &req);
+    regs_from_cpu(state, vmport_req, &req);
+}
+
+static void handle_ioreq(XenIOState *state, ioreq_t *req)
 {
-    if (!req->data_is_ptr && (req->dir == IOREQ_WRITE) &&
-            (req->size < sizeof (target_ulong))) {
+    if ((req->type != IOREQ_TYPE_VMWARE_PORT) && !req->data_is_ptr &&
+        (req->dir == IOREQ_WRITE) && (req->size < sizeof(target_ulong))) {
         req->data &= ((target_ulong) 1 << (8 * req->size)) - 1;
     }
 
@@ -787,6 +890,9 @@ 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, (vmware_ioreq_t *)req);
+            break;
         case IOREQ_TYPE_TIMEOFFSET:
             break;
         case IOREQ_TYPE_INVALIDATE:
@@ -828,7 +934,7 @@ 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 +963,27 @@ 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",
-                    req->state, req->data_is_ptr, req->addr,
-                    req->data, req->count, req->size);
+            if (req->type != IOREQ_TYPE_VMWARE_PORT) {
+                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
+                        ", type: %"FMT_ioreq_size"\n",
+                        req->state, req->data_is_ptr, req->addr,
+                        req->data, req->count, req->size, req->type);
+            } else {
+                vmware_ioreq_t *vp = (vmware_ioreq_t *)req;
+                fprintf(stderr,
+                        "Badness in I/O VMware request ... not in service?!: "
+                        "%x, ptr: 0, port: %x, data: %x"
+                        ", count: 1, size: %d\n",
+                        vp->state, (uint16_t)vp->edx, vp->eax,
+                        vp->size);
+            }
             destroy_hvm_domain(false);
             return;
         }
@@ -1028,6 +1147,9 @@ 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_ioreq_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? */
-- 
1.8.4