From 7977e603169c92da4b0ecd656c3346500a93897b Mon Sep 17 00:00:00 2001
From: Markus Armbruster <armbru@redhat.com>
Date: Fri, 28 Apr 2017 12:22:27 +0200
Subject: [PATCH 02/27] scsi: Disable deprecated implicit SCSI HBA creation
 more cleanly

RH-Author: Markus Armbruster <armbru@redhat.com>
Message-id: <1493382147-23057-2-git-send-email-armbru@redhat.com>
Patchwork-id: 74946
O-Subject: [RHV-7.4 qemu-kvm-rhev PATCH] scsi: Disable deprecated implicit SCSI HBA creation more cleanly
Bugzilla: 971799
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: John Snow <jsnow@redhat.com>
RH-Acked-by: Jeffrey Cody <jcody@redhat.com>

The PC machines (pc-q35-* pc-i440fx-* pc-* isapc xenfv) automatically
create lsi53c895a SCSI HBAs and SCSI devices to honor -drive if=scsi.
Deprecated upstream since commit f778a82, v2.9.0, not supported at all
in RHEL.  The way it fails is rather ugly, though:

    $ qemu-kvm -nodefaults -S -drive if=scsi,media=cdrom
    qemu-kvm: Unknown device 'lsi53c895a' for bus 'PCI'
    Aborted (core dumped)

Recent upstream work permit us to make this fail cleanly by commenting
out the code that tries to create lsi53c895a SCSI HBAs in
pc_pci_device_init():

    qemu-kvm: -drive if=scsi,media=cdrom: machine type does not support if=scsi,bus=0,unit=0

However, by itself this would make another deprecated feature
available in RHEL: drives defined with if=scsi get picked up by SCSI
HBAs added with -device, unlike other interface types.  Deprecated
upstream since commit a64aa57, v2.9.0.  Comment out that code, too.
Bonus: that code can be rather slow with a large number of drives, so
good riddance.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 hw/i386/pc.c       | 2 ++
 hw/scsi/scsi-bus.c | 7 +++++++
 vl.c               | 2 ++
 3 files changed, 11 insertions(+)

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 6ed4d23..1a0e672 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1648,6 +1648,7 @@ void pc_nic_init(ISABus *isa_bus, PCIBus *pci_bus)
 
 void pc_pci_device_init(PCIBus *pci_bus)
 {
+#if 0 /* Disabled for Red Hat Enterprise Linux */
     int max_bus;
     int bus;
 
@@ -1661,6 +1662,7 @@ void pc_pci_device_init(PCIBus *pci_bus)
          * this usage is deprecated.
          */
     }
+#endif
 }
 
 void ioapic_init_gsi(GSIState *gsi_state, const char *parent_name)
diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c
index f557446..bc984f4 100644
--- a/hw/scsi/scsi-bus.c
+++ b/hw/scsi/scsi-bus.c
@@ -265,6 +265,8 @@ SCSIDevice *scsi_bus_legacy_add_drive(SCSIBus *bus, BlockBackend *blk,
 
 void scsi_bus_legacy_handle_cmdline(SCSIBus *bus, bool deprecated)
 {
+#if 0 /* Disabled for Red Hat Enterprise Linux */
+
     Location loc;
     DriveInfo *dinfo;
     int unit;
@@ -291,8 +293,11 @@ void scsi_bus_legacy_handle_cmdline(SCSIBus *bus, bool deprecated)
                                   unit, false, -1, NULL, &error_fatal);
     }
     loc_pop(&loc);
+#endif
 }
 
+#if 0 /* Disabled for Red Hat Enterprise Linux */
+
 static bool is_scsi_hba_with_legacy_magic(Object *obj)
 {
     static const char *magic[] = {
@@ -329,6 +334,8 @@ void scsi_legacy_handle_cmdline(void)
                                    scsi_legacy_handle_cmdline_cb, NULL);
 }
 
+#endif
+
 static int32_t scsi_invalid_field(SCSIRequest *req, uint8_t *buf)
 {
     scsi_req_build_sense(req, SENSE_CODE(INVALID_FIELD));
diff --git a/vl.c b/vl.c
index 8a5df00..183f070 100644
--- a/vl.c
+++ b/vl.c
@@ -4602,6 +4602,7 @@ int main(int argc, char **argv, char **envp)
 
     rom_reset_order_override();
 
+#if 0 /* Disabled for Red Hat Enterprise Linux */
     /*
      * Create frontends for -drive if=scsi leftovers.
      * Normally, frontends for -drive get created by machine
@@ -4610,6 +4611,7 @@ int main(int argc, char **argv, char **envp)
      * implementation accident, and deprecated.
      */
     scsi_legacy_handle_cmdline();
+#endif
 
     /* Did we create any drives that we failed to create a device for? */
     drive_check_orphaned();
-- 
1.8.3.1