Revert "hw: report invalid disable-legacy|modern usage for virtio-1-only devs"

This reverts commit f2784eed306449c3d04a71a05ed6463b8289aedf
since that accidentally removes the PCIe capabilities from virtio
devices because virtio_pci_dc_realize is called before the new 'mode'
flag is set.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20190729162903.4489-3-dgilbert@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>

hw/core/machine.c

@@ -115,26 +115,9 @@ const size_t hw_compat_2_7_len = G_N_ELEMENTS(hw_compat_2_7);
 
 GlobalProperty hw_compat_2_6[] = {
     { "virtio-mmio", "format_transport_address", "off" },
-    /*
-     * don't include devices which are modern-only
-     * ie keyboard, mouse, tablet, gpu, vga & crypto
-     */
-    { "virtio-9p-pci", "disable-modern", "on" },
-    { "virtio-9p-pci", "disable-legacy", "off" },
-    { "virtio-balloon-pci", "disable-modern", "on" },
-    { "virtio-balloon-pci", "disable-legacy", "off" },
-    { "virtio-blk-pci", "disable-modern", "on" },
-    { "virtio-blk-pci", "disable-legacy", "off" },
-    { "virtio-input-host-pci", "disable-modern", "on" },
-    { "virtio-input-host-pci", "disable-legacy", "off" },
-    { "virtio-net-pci", "disable-modern", "on" },
-    { "virtio-net-pci", "disable-legacy", "off" },
-    { "virtio-rng-pci", "disable-modern", "on" },
-    { "virtio-rng-pci", "disable-legacy", "off" },
-    { "virtio-scsi-pci", "disable-modern", "on" },
-    { "virtio-scsi-pci", "disable-legacy", "off" },
-    { "virtio-serial-pci", "disable-modern", "on" },
-    { "virtio-serial-pci", "disable-legacy", "off" },
+    /* Optional because not all virtio-pci devices support legacy mode */
+    { "virtio-pci", "disable-modern", "on",  .optional = true },
+    { "virtio-pci", "disable-legacy", "off", .optional = true },
 };
 const size_t hw_compat_2_6_len = G_N_ELEMENTS(hw_compat_2_6);
 

hw/display/virtio-gpu-pci.c

@@ -33,9 +33,7 @@ static void virtio_gpu_pci_base_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
     Error *local_error = NULL;
 
     qdev_set_parent_bus(vdev, BUS(&vpci_dev->bus));
-    if (!virtio_pci_force_virtio_1(vpci_dev, errp)) {
-        return;
-    }
+    virtio_pci_force_virtio_1(vpci_dev);
     object_property_set_bool(OBJECT(vdev), true, "realized", &local_error);
 
     if (local_error) {

hw/display/virtio-vga.c

@@ -137,9 +137,7 @@ static void virtio_vga_base_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
 
     /* init virtio bits */
     qdev_set_parent_bus(DEVICE(g), BUS(&vpci_dev->bus));
-    if (!virtio_pci_force_virtio_1(vpci_dev, errp)) {
-        return;
-    }
+    virtio_pci_force_virtio_1(vpci_dev);
     object_property_set_bool(OBJECT(g), true, "realized", &err);
     if (err) {
         error_propagate(errp, err);

hw/virtio/virtio-crypto-pci.c

@@ -53,9 +53,7 @@ static void virtio_crypto_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
     }
 
     qdev_set_parent_bus(vdev, BUS(&vpci_dev->bus));
-    if (!virtio_pci_force_virtio_1(vpci_dev, errp)) {
-        return;
-    }
+    virtio_pci_force_virtio_1(vpci_dev);
     object_property_set_bool(OBJECT(vdev), true, "realized", errp);
     object_property_set_link(OBJECT(vcrypto),
                  OBJECT(vcrypto->vdev.conf.cryptodev), "cryptodev",

hw/virtio/virtio-input-pci.c

@@ -49,9 +49,7 @@ static void virtio_input_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
     DeviceState *vdev = DEVICE(&vinput->vdev);
 
     qdev_set_parent_bus(vdev, BUS(&vpci_dev->bus));
-    if (!virtio_pci_force_virtio_1(vpci_dev, errp)) {
-        return;
-    }
+    virtio_pci_force_virtio_1(vpci_dev);
     object_property_set_bool(OBJECT(vdev), true, "realized", errp);
 }
 

hw/virtio/virtio-pci.c

@@ -1723,22 +1723,16 @@ static void virtio_pci_realize(PCIDevice *pci_dev, Error **errp)
                        /* PCI BAR regions must be powers of 2 */
                        pow2ceil(proxy->notify.offset + proxy->notify.size));
 
-    if ((proxy->disable_legacy == ON_OFF_AUTO_ON) ||
-        ((proxy->disable_legacy == ON_OFF_AUTO_AUTO) && pcie_port)) {
-        if (proxy->disable_modern) {
-            error_setg(errp, "device cannot work as neither modern nor "
-                       "legacy mode is enabled");
-            error_append_hint(errp, "Set either disable-modern or "
-                              "disable-legacy to off\n");
-            return;
-        }
-        proxy->mode = VIRTIO_PCI_MODE_MODERN;
-    } else {
-        if (proxy->disable_modern) {
-            proxy->mode = VIRTIO_PCI_MODE_LEGACY;
-        } else {
-            proxy->mode = VIRTIO_PCI_MODE_TRANSITIONAL;
-        }
+    if (proxy->disable_legacy == ON_OFF_AUTO_AUTO) {
+        proxy->disable_legacy = pcie_port ? ON_OFF_AUTO_ON : ON_OFF_AUTO_OFF;
+    }
+
+    if (!virtio_pci_modern(proxy) && !virtio_pci_legacy(proxy)) {
+        error_setg(errp, "device cannot work as neither modern nor legacy mode"
+                   " is enabled");
+        error_append_hint(errp, "Set either disable-modern or disable-legacy"
+                          " to off\n");
+        return;
     }
 
     if (pcie_port && pci_is_express(pci_dev)) {

hw/virtio/virtio-pci.h

@@ -15,7 +15,6 @@
 #ifndef QEMU_VIRTIO_PCI_H
 #define QEMU_VIRTIO_PCI_H
 
-#include "qapi/error.h"
 #include "hw/pci/msi.h"
 #include "hw/virtio/virtio-bus.h"
 
@@ -119,12 +118,6 @@ typedef struct VirtIOPCIQueue {
   uint32_t used[2];
 } VirtIOPCIQueue;
 
-typedef enum {
-    VIRTIO_PCI_MODE_LEGACY,
-    VIRTIO_PCI_MODE_TRANSITIONAL,
-    VIRTIO_PCI_MODE_MODERN,
-} VirtIOPCIMode;
-
 struct VirtIOPCIProxy {
     PCIDevice pci_dev;
     MemoryRegion bar;
@@ -149,7 +142,6 @@ struct VirtIOPCIProxy {
     bool disable_modern;
     bool ignore_backend_features;
     OnOffAuto disable_legacy;
-    VirtIOPCIMode mode;
     uint32_t class_code;
     uint32_t nvectors;
     uint32_t dfselect;
@@ -164,34 +156,23 @@ struct VirtIOPCIProxy {
 
 static inline bool virtio_pci_modern(VirtIOPCIProxy *proxy)
 {
-    return proxy->mode != VIRTIO_PCI_MODE_LEGACY;
+    return !proxy->disable_modern;
 }
 
 static inline bool virtio_pci_legacy(VirtIOPCIProxy *proxy)
 {
-    return proxy->mode != VIRTIO_PCI_MODE_MODERN;
+    return proxy->disable_legacy == ON_OFF_AUTO_OFF;
 }
 
-static inline bool virtio_pci_force_virtio_1(VirtIOPCIProxy *proxy,
-                                             Error **errp)
+static inline void virtio_pci_force_virtio_1(VirtIOPCIProxy *proxy)
 {
-    if (proxy->disable_legacy == ON_OFF_AUTO_OFF) {
-        error_setg(errp, "Unable to set disable-legacy=off on a virtio-1.0 "
-                   "only device");
-        return false;
-    }
-    if (proxy->disable_modern == true) {
-        error_setg(errp, "Unable to set disable-modern=on on a virtio-1.0 "
-                   "only device");
-        return false;
-    }
-    proxy->mode = VIRTIO_PCI_MODE_MODERN;
-    return true;
+    proxy->disable_modern = false;
+    proxy->disable_legacy = ON_OFF_AUTO_ON;
 }
 
 static inline void virtio_pci_disable_modern(VirtIOPCIProxy *proxy)
 {
-    proxy->mode = VIRTIO_PCI_MODE_LEGACY;
+    proxy->disable_modern = true;
 }
 
 /*