pc: Reverse pc_init_pci() compatibility logic

Currently, the pc-1.4 machine init function enables PV EOI and then
calls the pc-1.2 machine init function. The problem with this approach
is that now we can't enable any additional compatibility code inside the
pc-1.2 init function because it would end up enabling the compatibility
behavior on pc-1.3 and pc-1.4 as well.

This reverses the logic so that the pc-1.2 machine init function will
disable PV EOI, and then call the pc-1.4 machine init function.

This way we can change older machine-types to enable compatibility
behavior, and the newer machine-types (pc-1.3, pc-q35-1.4 and
pc-i440fx-1.4) would just use the default behavior.

(This means that one nice side-effect of this change is that pc-q35-1.4
will get PV EOI enabled by default, too)

It would be interesting to eventually change pc_init_pci_no_kvmclock()
and pc_init_isa() to reuse pc_init_pci_1_2() as well (so we don't need
to duplicate compatibility code on those two functions). But this will
be probably much easier to do after we create a PCInitArgs struct for
the PC initialization arguments, and/or after we use global-properties
to implement the compatibility modes present in pc_init_pci_1_2().

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>

2 files changed, 4 insertions, 3 deletions

diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index ac2ec243e1..db9086e7ce 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -211,11 +211,12 @@ static uint32_t kvm_default_features = (1 << KVM_FEATURE_CLOCKSOURCE) |
         (1 << KVM_FEATURE_CLOCKSOURCE2) |
         (1 << KVM_FEATURE_ASYNC_PF) |
         (1 << KVM_FEATURE_STEAL_TIME) |
+        (1 << KVM_FEATURE_PV_EOI) |
         (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT);
 
-void enable_kvm_pv_eoi(void)
+void disable_kvm_pv_eoi(void)
 {
-    kvm_default_features |= (1UL << KVM_FEATURE_PV_EOI);
+    kvm_default_features &= ~(1UL << KVM_FEATURE_PV_EOI);
 }
 
 void host_cpuid(uint32_t function, uint32_t count,
diff --git a/target-i386/cpu.h b/target-i386/cpu.h
index 4e091cdec3..9d4fcf93b6 100644
--- a/target-i386/cpu.h
+++ b/target-i386/cpu.h
@@ -1250,7 +1250,7 @@ void do_smm_enter(CPUX86State *env1);
 
 void cpu_report_tpr_access(CPUX86State *env, TPRAccess access);
 
-void enable_kvm_pv_eoi(void);
+void disable_kvm_pv_eoi(void);
 
 /* Return name of 32-bit register, from a R_* constant */
 const char *get_register_name_32(unsigned int reg);