[PATCH v12 14/19] multi-process: Forward PCI config space acceses to the remote process

[Jagannathan Raman <jag.raman@oracle.com>]

From: Elena Ufimtseva <elena.ufimtseva@oracle.com>

The Proxy Object sends the PCI config space accesses as messages
to the remote process over the communication channel

Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/hw/remote/mpqemu-link.h |  9 ++++++
 hw/remote/message.c             | 62 +++++++++++++++++++++++++++++++++++++++++
 hw/remote/mpqemu-link.c         |  6 ++++
 hw/remote/proxy.c               | 51 +++++++++++++++++++++++++++++++++
 4 files changed, 128 insertions(+)

diff --git a/include/hw/remote/mpqemu-link.h b/include/hw/remote/mpqemu-link.h
index cee9468..057c98b 100644
--- a/include/hw/remote/mpqemu-link.h
+++ b/include/hw/remote/mpqemu-link.h
@@ -34,6 +34,8 @@ typedef enum {
     MPQEMU_CMD_INIT,
     SYNC_SYSMEM,
     RET_MSG,
+    PCI_CONFIG_WRITE,
+    PCI_CONFIG_READ,
     MPQEMU_CMD_MAX,
 } MPQemuCmd;
 
@@ -43,6 +45,12 @@ typedef struct {
     off_t offsets[REMOTE_MAX_FDS];
 } SyncSysmemMsg;
 
+typedef struct {
+    uint32_t addr;
+    uint32_t val;
+    int l;
+} PciConfDataMsg;
+
 /**
  * MPQemuMsg:
  * @cmd: The remote command
@@ -60,6 +68,7 @@ typedef struct {
 
     union {
         uint64_t u64;
+        PciConfDataMsg pci_conf_data;
         SyncSysmemMsg sync_sysmem;
     } data;
 
diff --git a/hw/remote/message.c b/hw/remote/message.c
index 1f2edc7..52a6f6f 100644
--- a/hw/remote/message.c
+++ b/hw/remote/message.c
@@ -15,6 +15,12 @@
 #include "hw/remote/mpqemu-link.h"
 #include "qapi/error.h"
 #include "sysemu/runstate.h"
+#include "hw/pci/pci.h"
+
+static void process_config_write(QIOChannel *ioc, PCIDevice *dev,
+                                 MPQemuMsg *msg);
+static void process_config_read(QIOChannel *ioc, PCIDevice *dev,
+                                MPQemuMsg *msg);
 
 void coroutine_fn mpqemu_remote_msg_loop_co(void *data)
 {
@@ -43,6 +49,12 @@ void coroutine_fn mpqemu_remote_msg_loop_co(void *data)
         }
 
         switch (msg.cmd) {
+        case PCI_CONFIG_WRITE:
+            process_config_write(com->ioc, pci_dev, &msg);
+            break;
+        case PCI_CONFIG_READ:
+            process_config_read(com->ioc, pci_dev, &msg);
+            break;
         default:
             error_setg(&local_err,
                        "Unknown command (%d) received for device %s (pid=%d)",
@@ -60,3 +72,53 @@ void coroutine_fn mpqemu_remote_msg_loop_co(void *data)
 
     return;
 }
+
+static void process_config_write(QIOChannel *ioc, PCIDevice *dev,
+                                 MPQemuMsg *msg)
+{
+    PciConfDataMsg *conf = (PciConfDataMsg *)&msg->data.pci_conf_data;
+    MPQemuMsg ret = { 0 };
+    Error *local_err = NULL;
+
+    if ((conf->addr + sizeof(conf->val)) > pci_config_size(dev)) {
+        error_report("Bad address received when writing PCI config, pid %d",
+                     getpid());
+        ret.data.u64 = UINT64_MAX;
+    } else {
+        pci_default_write_config(dev, conf->addr, conf->val, conf->l);
+    }
+
+    ret.cmd = RET_MSG;
+    ret.size = sizeof(ret.data.u64);
+
+    mpqemu_msg_send(&ret, ioc, &local_err);
+    if (local_err) {
+        error_report("Could not send message to proxy from pid %d",
+                     getpid());
+    }
+}
+
+static void process_config_read(QIOChannel *ioc, PCIDevice *dev,
+                                MPQemuMsg *msg)
+{
+    PciConfDataMsg *conf = (PciConfDataMsg *)&msg->data.pci_conf_data;
+    MPQemuMsg ret = { 0 };
+    Error *local_err = NULL;
+
+    if ((conf->addr + sizeof(conf->val)) > pci_config_size(dev)) {
+        error_report("Bad address received when reading PCI config, pid %d",
+                     getpid());
+        ret.data.u64 = UINT64_MAX;
+    } else {
+        ret.data.u64 = pci_default_read_config(dev, conf->addr, conf->l);
+    }
+
+    ret.cmd = RET_MSG;
+    ret.size = sizeof(ret.data.u64);
+
+    mpqemu_msg_send(&ret, ioc, &local_err);
+    if (local_err) {
+        error_report("Could not send message to proxy from pid %d",
+                     getpid());
+    }
+}
diff --git a/hw/remote/mpqemu-link.c b/hw/remote/mpqemu-link.c
index 18c8a54..83dbd65 100644
--- a/hw/remote/mpqemu-link.c
+++ b/hw/remote/mpqemu-link.c
@@ -283,6 +283,12 @@ bool mpqemu_msg_valid(MPQemuMsg *msg)
             return false;
         }
         break;
+    case PCI_CONFIG_WRITE:
+    case PCI_CONFIG_READ:
+        if (msg->size != sizeof(PciConfDataMsg)) {
+            return false;
+        }
+        break;
     default:
         break;
     }
diff --git a/hw/remote/proxy.c b/hw/remote/proxy.c
index 29100bc..c193484 100644
--- a/hw/remote/proxy.c
+++ b/hw/remote/proxy.c
@@ -16,6 +16,8 @@
 #include "hw/qdev-properties.h"
 #include "monitor/monitor.h"
 #include "migration/blocker.h"
+#include "hw/remote/mpqemu-link.h"
+#include "qemu/error-report.h"
 
 static void proxy_set_socket(PCIProxyDev *pdev, int fd, Error **errp)
 {
@@ -69,6 +71,52 @@ static void pci_proxy_dev_exit(PCIDevice *pdev)
     error_free(dev->migration_blocker);
 }
 
+static int config_op_send(PCIProxyDev *pdev, uint32_t addr, uint32_t *val,
+                          int l, unsigned int op)
+{
+    MPQemuMsg msg = { 0 };
+    uint64_t ret = -EINVAL;
+    Error *local_err = NULL;
+
+    msg.cmd = op;
+    msg.data.pci_conf_data.addr = addr;
+    msg.data.pci_conf_data.val = (op == PCI_CONFIG_WRITE) ? *val : 0;
+    msg.data.pci_conf_data.l = l;
+    msg.size = sizeof(PciConfDataMsg);
+
+    ret = mpqemu_msg_send_and_await_reply(&msg, pdev, &local_err);
+    if (local_err) {
+        error_report_err(local_err);
+    }
+    if (op == PCI_CONFIG_READ) {
+        *val = (uint32_t)ret;
+    }
+
+    return ret;
+}
+
+static uint32_t pci_proxy_read_config(PCIDevice *d, uint32_t addr, int len)
+{
+    uint32_t val;
+
+    (void)config_op_send(PCI_PROXY_DEV(d), addr, &val, len, PCI_CONFIG_READ);
+
+    return val;
+}
+
+static void pci_proxy_write_config(PCIDevice *d, uint32_t addr, uint32_t val,
+                                   int l)
+{
+    /*
+     * Some of the functions access the copy of remote device's PCI config
+     * space which is cached in the proxy device. Therefore, maintain
+     * it updated.
+     */
+    pci_default_write_config(d, addr, val, l);
+
+    (void)config_op_send(PCI_PROXY_DEV(d), addr, &val, l, PCI_CONFIG_WRITE);
+}
+
 static void pci_proxy_dev_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
@@ -76,6 +124,9 @@ static void pci_proxy_dev_class_init(ObjectClass *klass, void *data)
 
     k->realize = pci_proxy_dev_realize;
     k->exit = pci_proxy_dev_exit;
+    k->config_read = pci_proxy_read_config;
+    k->config_write = pci_proxy_write_config;
+
     device_class_set_props(dc, proxy_properties);
 }
 
-- 
1.8.3.1