We want to get rid of the "#ifdef TARGET_X86_64" compile-time switch
in the long run, so we can drop the separate compilation of the
"qemu-system-i386" binary one day - but we then still need a way to
run a guest with max. CPU settings in 32-bit mode. So the "max" CPU
should determine its family/model/stepping settings according to the
"large mode" (LM) CPU feature bit during runtime, so that it is
possible to run "qemu-system-x86_64 -cpu max,lm=off" and still get
a sane family/model/stepping setting for the guest CPU.
To be able to check the LM bit, we have to move the code that sets
up these properties to a "realize" function, since the LM setting is
not available yet when the "instance_init" function is being called.
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
target/i386/cpu.c | 31 ++++++++++++++++++++++---------
1 file changed, 22 insertions(+), 9 deletions(-)
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index cab1e2a957..fe3b78fc95 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -44,6 +44,8 @@
#include "disas/capstone.h"
#include "cpu-internal.h"
+static void x86_cpu_realizefn(DeviceState *dev, Error **errp);
+
/* Helpers for building CPUID[2] descriptors: */
struct CPUID2CacheDescriptorInfo {
@@ -4315,6 +4317,25 @@ static Property max_x86_cpu_properties[] = {
DEFINE_PROP_END_OF_LIST()
};
+static void max_x86_cpu_realize(DeviceState *dev, Error **errp)
+{
+ Object *obj = OBJECT(dev);
+
+ if (!object_property_get_int(obj, "family", &error_abort)) {
+ if (X86_CPU(obj)->env.features[FEAT_8000_0001_EDX] & CPUID_EXT2_LM) {
+ object_property_set_int(obj, "family", 15, &error_abort);
+ object_property_set_int(obj, "model", 107, &error_abort);
+ object_property_set_int(obj, "stepping", 1, &error_abort);
+ } else {
+ object_property_set_int(obj, "family", 6, &error_abort);
+ object_property_set_int(obj, "model", 6, &error_abort);
+ object_property_set_int(obj, "stepping", 3, &error_abort);
+ }
+ }
+
+ x86_cpu_realizefn(dev, errp);
+}
+
static void max_x86_cpu_class_init(ObjectClass *oc, void *data)
{
DeviceClass *dc = DEVICE_CLASS(oc);
@@ -4326,6 +4347,7 @@ static void max_x86_cpu_class_init(ObjectClass *oc, void *data)
"Enables all features supported by the accelerator in the current host";
device_class_set_props(dc, max_x86_cpu_properties);
+ dc->realize = max_x86_cpu_realize;
}
static void max_x86_cpu_initfn(Object *obj)
@@ -4344,15 +4366,6 @@ static void max_x86_cpu_initfn(Object *obj)
*/
object_property_set_str(OBJECT(cpu), "vendor", CPUID_VENDOR_AMD,
&error_abort);
-#ifdef TARGET_X86_64
- object_property_set_int(OBJECT(cpu), "family", 15, &error_abort);
- object_property_set_int(OBJECT(cpu), "model", 107, &error_abort);
- object_property_set_int(OBJECT(cpu), "stepping", 1, &error_abort);
-#else
- object_property_set_int(OBJECT(cpu), "family", 6, &error_abort);
- object_property_set_int(OBJECT(cpu), "model", 6, &error_abort);
- object_property_set_int(OBJECT(cpu), "stepping", 3, &error_abort);
-#endif
object_property_set_str(OBJECT(cpu), "model-id",
"QEMU TCG CPU version " QEMU_HW_VERSION,
&error_abort);
--
2.31.1
On Mon, Mar 06, 2023 at 04:43:11PM +0100, Thomas Huth wrote: > We want to get rid of the "#ifdef TARGET_X86_64" compile-time switch > in the long run, so we can drop the separate compilation of the > "qemu-system-i386" binary one day - but we then still need a way to > run a guest with max. CPU settings in 32-bit mode. So the "max" CPU > should determine its family/model/stepping settings according to the > "large mode" (LM) CPU feature bit during runtime, so that it is > possible to run "qemu-system-x86_64 -cpu max,lm=off" and still get > a sane family/model/stepping setting for the guest CPU. > > To be able to check the LM bit, we have to move the code that sets > up these properties to a "realize" function, since the LM setting is > not available yet when the "instance_init" function is being called. Ah, yes, makes sense. > > Signed-off-by: Thomas Huth <thuth@redhat.com> > --- > target/i386/cpu.c | 31 ++++++++++++++++++++++--------- > 1 file changed, 22 insertions(+), 9 deletions(-) Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> > > diff --git a/target/i386/cpu.c b/target/i386/cpu.c > index cab1e2a957..fe3b78fc95 100644 > --- a/target/i386/cpu.c > +++ b/target/i386/cpu.c > @@ -44,6 +44,8 @@ > #include "disas/capstone.h" > #include "cpu-internal.h" > > +static void x86_cpu_realizefn(DeviceState *dev, Error **errp); > + > /* Helpers for building CPUID[2] descriptors: */ > > struct CPUID2CacheDescriptorInfo { > @@ -4315,6 +4317,25 @@ static Property max_x86_cpu_properties[] = { > DEFINE_PROP_END_OF_LIST() > }; > > +static void max_x86_cpu_realize(DeviceState *dev, Error **errp) > +{ > + Object *obj = OBJECT(dev); > + > + if (!object_property_get_int(obj, "family", &error_abort)) { > + if (X86_CPU(obj)->env.features[FEAT_8000_0001_EDX] & CPUID_EXT2_LM) { > + object_property_set_int(obj, "family", 15, &error_abort); > + object_property_set_int(obj, "model", 107, &error_abort); > + object_property_set_int(obj, "stepping", 1, &error_abort); > + } else { > + object_property_set_int(obj, "family", 6, &error_abort); > + object_property_set_int(obj, "model", 6, &error_abort); > + object_property_set_int(obj, "stepping", 3, &error_abort); > + } > + } > + > + x86_cpu_realizefn(dev, errp); > +} > + > static void max_x86_cpu_class_init(ObjectClass *oc, void *data) > { > DeviceClass *dc = DEVICE_CLASS(oc); > @@ -4326,6 +4347,7 @@ static void max_x86_cpu_class_init(ObjectClass *oc, void *data) > "Enables all features supported by the accelerator in the current host"; > > device_class_set_props(dc, max_x86_cpu_properties); > + dc->realize = max_x86_cpu_realize; > } > > static void max_x86_cpu_initfn(Object *obj) > @@ -4344,15 +4366,6 @@ static void max_x86_cpu_initfn(Object *obj) > */ > object_property_set_str(OBJECT(cpu), "vendor", CPUID_VENDOR_AMD, > &error_abort); > -#ifdef TARGET_X86_64 > - object_property_set_int(OBJECT(cpu), "family", 15, &error_abort); > - object_property_set_int(OBJECT(cpu), "model", 107, &error_abort); > - object_property_set_int(OBJECT(cpu), "stepping", 1, &error_abort); > -#else > - object_property_set_int(OBJECT(cpu), "family", 6, &error_abort); > - object_property_set_int(OBJECT(cpu), "model", 6, &error_abort); > - object_property_set_int(OBJECT(cpu), "stepping", 3, &error_abort); > -#endif > object_property_set_str(OBJECT(cpu), "model-id", > "QEMU TCG CPU version " QEMU_HW_VERSION, > &error_abort); > -- > 2.31.1 > With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
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