On Tue, Mar 02, 2021 at 06:35:44PM +0100, Halil Pasic wrote: > Since the virtio-gpu-ccw device depends on the hw-display-virtio-gpu > module, which provides the type virtio-gpu-device, packaging the > hw-display-virtio-gpu module as a separate package that may or may not > be installed along with the qemu package leads to problems. Namely if > the hw-display-virtio-gpu is absent, qemu continues to advertise > virtio-gpu-ccw, but it aborts not only when one attempts using > virtio-gpu-ccw, but also when libvirtd's capability probing tries > to instantiate the type to introspect it. > > Let us thus introduce a module named hw-s390x-virtio-gpu-ccw that > is going to provide the virtio-gpu-ccw device. The hw-s390x prefix > was chosen because it is not a portable device. Because registering > virtio-gpu-ccw would make non-s390x emulator fail due to a missing > parent type, if built as a module, before registering it, we check > if the ancestor types are already registered.
I don't understand what makes it necessary to make the type_register() call conditional. Calling type_register() before the parent types are registered is perfectly valid. I don't think we should prevent type_register() from being called. We just need to prevent type_initialize() from being called unless the type definition is complete. This way there won't be any tricky module loading order requirements. > > With virtio-gpu-ccw built as a module, the correct way to package a > modularized qemu is to require that hw-display-virtio-gpu must be > installed whenever the module hw-s390x-virtio-gpu-ccw. > > The definition S390_ADAPTER_SUPPRESSIBLE was moved to "cpu.h", per > suggestion of Thomas Huth. From interface design perspective, IMHO, not > a good thing as it belongs to the public interface of > css_register_io_adapters(). We did this because CONFIG_KVM requeires > NEED_CPU_H and Thomas, and other commenters did not like the > consequences of that. > > Moving the interrupt related declarations to s390_flic.h was suggested > by Cornelia Huck. > > Signed-off-by: Halil Pasic <pa...@linux.ibm.com> > --- > > As explained in [1] the previous idea of type_register_mayfail() does > not work. The next best thing is to check if all types we need are > already registered before registering virtio-gpu-ccw from the module. It > is reasonable to assume that when the module is loaded, the ancestors > are already registered (which is not the case if the device is a > built in one). > > The alternatives to this approch I could identify are: > * A poor mans version of this which checks for the parent > * Emulator specific modules: > * An emulator specific directory within the modules directory which > is ignored by the other emulators. > * A way to tell the shared util library the name of this directory, > and the code to check it if set. > * Build hw-s390x-virtio-gpu-ccw so it lands in this special directory > in the build tree, and install it there as well. > I've spend some time with looking into this, but I came to the > conclusion that the two latter points look hairy. > > [1] > https://lore.kernel.org/qemu-devel/20210222125548.346166-1-pa...@linux.ibm.com/T/#maf0608df5479f87b23606f01f732740d2617b458 > --- > hw/s390x/meson.build | 7 ++++- > hw/s390x/virtio-ccw-gpu.c | 5 ++++ > include/hw/s390x/css.h | 7 ----- > include/hw/s390x/s390_flic.h | 3 +++ > include/qom/object.h | 10 ++++++++ > qom/object.c | 50 ++++++++++++++++++++++++++++++++++++ > target/s390x/cpu.h | 9 ++++--- > util/module.c | 1 + > 8 files changed, 81 insertions(+), 11 deletions(-) I suggest splitting the QOM core changes and s390x-specific changes into separate patches, so they can be reviewed and included separately. > > diff --git a/hw/s390x/meson.build b/hw/s390x/meson.build > index 2a7818d94b..7ac972afcf 100644 > --- a/hw/s390x/meson.build > +++ b/hw/s390x/meson.build > @@ -34,7 +34,6 @@ virtio_ss.add(files('virtio-ccw.c')) > virtio_ss.add(when: 'CONFIG_VIRTIO_BALLOON', if_true: > files('virtio-ccw-balloon.c')) > virtio_ss.add(when: 'CONFIG_VIRTIO_BLK', if_true: files('virtio-ccw-blk.c')) > virtio_ss.add(when: 'CONFIG_VIRTIO_CRYPTO', if_true: > files('virtio-ccw-crypto.c')) > -virtio_ss.add(when: 'CONFIG_VIRTIO_GPU', if_true: files('virtio-ccw-gpu.c')) > virtio_ss.add(when: 'CONFIG_VIRTIO_INPUT', if_true: > files('virtio-ccw-input.c')) > virtio_ss.add(when: 'CONFIG_VIRTIO_NET', if_true: files('virtio-ccw-net.c')) > virtio_ss.add(when: 'CONFIG_VIRTIO_RNG', if_true: files('virtio-ccw-rng.c')) > @@ -46,3 +45,9 @@ virtio_ss.add(when: 'CONFIG_VHOST_USER_FS', if_true: > files('vhost-user-fs-ccw.c' > s390x_ss.add_all(when: 'CONFIG_VIRTIO_CCW', if_true: virtio_ss) > > hw_arch += {'s390x': s390x_ss} > + > +hw_s390x_modules = {} > +virtio_gpu_ccw_ss = ss.source_set() > +virtio_gpu_ccw_ss.add(when: 'CONFIG_VIRTIO_GPU', if_true: > [files('virtio-ccw-gpu.c'), pixman]) > +hw_s390x_modules += {'virtio-gpu-ccw': virtio_gpu_ccw_ss} > +modules += {'hw-s390x': hw_s390x_modules} > diff --git a/hw/s390x/virtio-ccw-gpu.c b/hw/s390x/virtio-ccw-gpu.c > index c301e2586b..ccdf6ac20f 100644 > --- a/hw/s390x/virtio-ccw-gpu.c > +++ b/hw/s390x/virtio-ccw-gpu.c > @@ -62,6 +62,11 @@ static const TypeInfo virtio_ccw_gpu = { > > static void virtio_ccw_gpu_register(void) > { > +#ifdef CONFIG_MODULES > + if (!type_ancestors_registered(&virtio_ccw_gpu)) { > + return; > + } > +#endif > type_register_static(&virtio_ccw_gpu); > } > > diff --git a/include/hw/s390x/css.h b/include/hw/s390x/css.h > index 08c869ab0a..7858666307 100644 > --- a/include/hw/s390x/css.h > +++ b/include/hw/s390x/css.h > @@ -12,7 +12,6 @@ > #ifndef CSS_H > #define CSS_H > > -#include "cpu.h" > #include "hw/s390x/adapter.h" > #include "hw/s390x/s390_flic.h" > #include "hw/s390x/ioinst.h" > @@ -233,12 +232,6 @@ uint32_t css_get_adapter_id(CssIoAdapterType type, > uint8_t isc); > void css_register_io_adapters(CssIoAdapterType type, bool swap, bool > maskable, > uint8_t flags, Error **errp); > > -#ifndef CONFIG_KVM > -#define S390_ADAPTER_SUPPRESSIBLE 0x01 > -#else > -#define S390_ADAPTER_SUPPRESSIBLE KVM_S390_ADAPTER_SUPPRESSIBLE > -#endif > - > #ifndef CONFIG_USER_ONLY > SubchDev *css_find_subch(uint8_t m, uint8_t cssid, uint8_t ssid, > uint16_t schid); > diff --git a/include/hw/s390x/s390_flic.h b/include/hw/s390x/s390_flic.h > index e91b15d2d6..3907a13d07 100644 > --- a/include/hw/s390x/s390_flic.h > +++ b/include/hw/s390x/s390_flic.h > @@ -134,6 +134,9 @@ void s390_flic_init(void); > S390FLICState *s390_get_flic(void); > QEMUS390FLICState *s390_get_qemu_flic(S390FLICState *fs); > S390FLICStateClass *s390_get_flic_class(S390FLICState *fs); > +void s390_crw_mchk(void); > +void s390_io_interrupt(uint16_t subchannel_id, uint16_t subchannel_nr, > + uint32_t io_int_parm, uint32_t io_int_word); > bool ais_needed(void *opaque); > > #endif /* HW_S390_FLIC_H */ > diff --git a/include/qom/object.h b/include/qom/object.h > index 6721cd312e..7aa996a042 100644 > --- a/include/qom/object.h > +++ b/include/qom/object.h > @@ -815,6 +815,16 @@ ObjectClass *object_get_class(Object *obj); > */ > const char *object_get_typename(const Object *obj); > > +/** > + * type_ancestors_registered: > + * @info: The #TypeInfo of the type > + * > + * Returns: true if all the ancestor types, that is classes and interfaces > this > + * type inherits form are all already registered, false if there is an > ancestor > + * that ain't registered yet > + */ > +bool type_ancestors_registered(const TypeInfo *info); > + > /** > * type_register_static: > * @info: The #TypeInfo of the new type. > diff --git a/qom/object.c b/qom/object.c > index 491823db4a..03bd9aa2ba 100644 > --- a/qom/object.c > +++ b/qom/object.c > @@ -281,6 +281,56 @@ static void object_property_free(gpointer data) > g_free(prop); > } > > +static TypeImpl *type_get_parent_const(const TypeImpl *ti) > +{ > + return ti->parent_type ? ti->parent_type : type_get_by_name(ti->parent); > +} > + > + > +static bool __type_ancestors_registered(const TypeImpl *ti) > +{ > + TypeImpl *parent; > + int i; > + > + if (!ti) { > + return false; > + } > + > + if (ti->class) { > + /* fully initialized */ > + return true; > + } > + > + for (i = 0; i < ti->num_interfaces; i++) { > + if (!type_get_by_name(ti->interfaces[i].typename)) { > + return false; > + } > + } > + if (ti->parent) { > + parent = type_get_parent_const(ti); > + if (!parent) { > + return false; > + } > + return __type_ancestors_registered(parent); > + } > + return true; > +} > + > +bool type_ancestors_registered(const TypeInfo *info) > +{ > + int i; > + > + for (i = 0; info->interfaces && info->interfaces[i].type; i++) { > + if (!type_get_by_name(info->interfaces[i].type)) { > + return false; > + } > + } > + if (info->parent) { > + return __type_ancestors_registered(type_get_by_name(info->parent)); > + } > + return true; > +} > + > static void type_initialize(TypeImpl *ti) > { > TypeImpl *parent; > diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h > index 60d434d5ed..b434b905c0 100644 > --- a/target/s390x/cpu.h > +++ b/target/s390x/cpu.h > @@ -40,6 +40,12 @@ > > #define S390_MAX_CPUS 248 > > +#ifndef CONFIG_KVM > +#define S390_ADAPTER_SUPPRESSIBLE 0x01 > +#else > +#define S390_ADAPTER_SUPPRESSIBLE KVM_S390_ADAPTER_SUPPRESSIBLE > +#endif > + > typedef struct PSW { > uint64_t mask; > uint64_t addr; > @@ -806,9 +812,6 @@ int cpu_s390x_signal_handler(int host_signum, void > *pinfo, void *puc); > > > /* interrupt.c */ > -void s390_crw_mchk(void); > -void s390_io_interrupt(uint16_t subchannel_id, uint16_t subchannel_nr, > - uint32_t io_int_parm, uint32_t io_int_word); > #define RA_IGNORED 0 > void s390_program_interrupt(CPUS390XState *env, uint32_t code, uintptr_t ra); > /* service interrupts are floating therefore we must not pass an cpustate */ > diff --git a/util/module.c b/util/module.c > index c65060c167..cbe89fede6 100644 > --- a/util/module.c > +++ b/util/module.c > @@ -304,6 +304,7 @@ static struct { > { "virtio-gpu-pci-base", "hw-", "display-virtio-gpu-pci" }, > { "virtio-gpu-pci", "hw-", "display-virtio-gpu-pci" }, > { "vhost-user-gpu-pci", "hw-", "display-virtio-gpu-pci" }, > + { "virtio-gpu-ccw", "hw-", "s390x-virtio-gpu-ccw" }, > { "virtio-vga-base", "hw-", "display-virtio-vga" }, > { "virtio-vga", "hw-", "display-virtio-vga" }, > { "vhost-user-vga", "hw-", "display-virtio-vga" }, > > base-commit: 1af5629673bb5c1592d993f9fb6119a62845f576 > -- > 2.25.1 > -- Eduardo
