| Message ID | 20170629132310.18865-2-marcandre.lureau@redhat.com |
|---|---|
| State | New |
| Headers | show |
On Thu, Jun 29, 2017 at 03:23:04PM +0200, Marc-André Lureau wrote: > This compat property sole function is to prevent the device from being > instantiated. Instead of requiring an extra compat property, check if > fw_cfg has DMA enabled. > > This has the additional benefit of handling other cases properly, like: > > $ qemu-system-x86_64 -device vmgenid -machine none > qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in fw_cfg, which this machine type does not provide > $ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.9 -global fw_cfg.dma_enabled=off > qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in fw_cfg, which this machine type does not provide > $ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.6 -global fw_cfg.dma_enabled=on > [boots normally] > > Suggested-by: Eduardo Habkost <ehabkost@redhat.com> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> I like this Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Which tree would you like to merge this through? > --- > include/hw/acpi/bios-linker-loader.h | 2 ++ > include/hw/compat.h | 4 ---- > hw/acpi/bios-linker-loader.c | 6 ++++++ > hw/acpi/vmgenid.c | 9 +-------- > 4 files changed, 9 insertions(+), 12 deletions(-) > > diff --git a/include/hw/acpi/bios-linker-loader.h b/include/hw/acpi/bios-linker-loader.h > index efe17b0b9c..a711dbced8 100644 > --- a/include/hw/acpi/bios-linker-loader.h > +++ b/include/hw/acpi/bios-linker-loader.h > @@ -7,6 +7,8 @@ typedef struct BIOSLinker { > GArray *file_list; > } BIOSLinker; > > +bool bios_linker_loader_can_write_pointer(void); > + > BIOSLinker *bios_linker_loader_init(void); > > void bios_linker_loader_alloc(BIOSLinker *linker, > diff --git a/include/hw/compat.h b/include/hw/compat.h > index 26cd5851a5..36f02179ac 100644 > --- a/include/hw/compat.h > +++ b/include/hw/compat.h > @@ -150,10 +150,6 @@ > .driver = "fw_cfg_io",\ > .property = "dma_enabled",\ > .value = "off",\ > - },{\ > - .driver = "vmgenid",\ > - .property = "x-write-pointer-available",\ > - .value = "off",\ > }, > > #define HW_COMPAT_2_3 \ > diff --git a/hw/acpi/bios-linker-loader.c b/hw/acpi/bios-linker-loader.c > index 046183a0f1..587d62cb93 100644 > --- a/hw/acpi/bios-linker-loader.c > +++ b/hw/acpi/bios-linker-loader.c > @@ -168,6 +168,12 @@ bios_linker_find_file(const BIOSLinker *linker, const char *name) > return NULL; > } > > +bool bios_linker_loader_can_write_pointer(void) > +{ > + FWCfgState *fw_cfg = fw_cfg_find(); > + return fw_cfg && fw_cfg_dma_enabled(fw_cfg); > +} > + > /* > * bios_linker_loader_alloc: ask guest to load file into guest memory. > * > diff --git a/hw/acpi/vmgenid.c b/hw/acpi/vmgenid.c > index a32b847fe0..ab5da293fd 100644 > --- a/hw/acpi/vmgenid.c > +++ b/hw/acpi/vmgenid.c > @@ -205,17 +205,11 @@ static void vmgenid_handle_reset(void *opaque) > memset(vms->vmgenid_addr_le, 0, ARRAY_SIZE(vms->vmgenid_addr_le)); > } > > -static Property vmgenid_properties[] = { > - DEFINE_PROP_BOOL("x-write-pointer-available", VmGenIdState, > - write_pointer_available, true), > - DEFINE_PROP_END_OF_LIST(), > -}; > - > static void vmgenid_realize(DeviceState *dev, Error **errp) > { > VmGenIdState *vms = VMGENID(dev); > > - if (!vms->write_pointer_available) { > + if (!bios_linker_loader_can_write_pointer()) { > error_setg(errp, "%s requires DMA write support in fw_cfg, " > "which this machine type does not provide", VMGENID_DEVICE); > return; > @@ -239,7 +233,6 @@ static void vmgenid_device_class_init(ObjectClass *klass, void *data) > dc->vmsd = &vmstate_vmgenid; > dc->realize = vmgenid_realize; > dc->hotpluggable = false; > - dc->props = vmgenid_properties; > > object_class_property_add_str(klass, VMGENID_GUID, NULL, > vmgenid_set_guid, NULL); > -- > 2.13.1.395.gf7b71de06
Nice improvement! > On Jun 29, 2017, at 9:23 AM, Marc-André Lureau <marcandre.lureau@redhat.com> wrote: > > This compat property sole function is to prevent the device from being > instantiated. Instead of requiring an extra compat property, check if > fw_cfg has DMA enabled. > > This has the additional benefit of handling other cases properly, like: > > $ qemu-system-x86_64 -device vmgenid -machine none > qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in fw_cfg, which this machine type does not provide > $ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.9 -global fw_cfg.dma_enabled=off > qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in fw_cfg, which this machine type does not provide > $ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.6 -global fw_cfg.dma_enabled=on > [boots normally] > > Suggested-by: Eduardo Habkost <ehabkost@redhat.com> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Ben Warren <ben@skyportsystems.com <mailto:mst@redhat.com>> > --- > include/hw/acpi/bios-linker-loader.h | 2 ++ > include/hw/compat.h | 4 ---- > hw/acpi/bios-linker-loader.c | 6 ++++++ > hw/acpi/vmgenid.c | 9 +-------- > 4 files changed, 9 insertions(+), 12 deletions(-) > > diff --git a/include/hw/acpi/bios-linker-loader.h b/include/hw/acpi/bios-linker-loader.h > index efe17b0b9c..a711dbced8 100644 > --- a/include/hw/acpi/bios-linker-loader.h > +++ b/include/hw/acpi/bios-linker-loader.h > @@ -7,6 +7,8 @@ typedef struct BIOSLinker { > GArray *file_list; > } BIOSLinker; > > +bool bios_linker_loader_can_write_pointer(void); > + > BIOSLinker *bios_linker_loader_init(void); > > void bios_linker_loader_alloc(BIOSLinker *linker, > diff --git a/include/hw/compat.h b/include/hw/compat.h > index 26cd5851a5..36f02179ac 100644 > --- a/include/hw/compat.h > +++ b/include/hw/compat.h > @@ -150,10 +150,6 @@ > .driver = "fw_cfg_io",\ > .property = "dma_enabled",\ > .value = "off",\ > - },{\ > - .driver = "vmgenid",\ > - .property = "x-write-pointer-available",\ > - .value = "off",\ > }, > > #define HW_COMPAT_2_3 \ > diff --git a/hw/acpi/bios-linker-loader.c b/hw/acpi/bios-linker-loader.c > index 046183a0f1..587d62cb93 100644 > --- a/hw/acpi/bios-linker-loader.c > +++ b/hw/acpi/bios-linker-loader.c > @@ -168,6 +168,12 @@ bios_linker_find_file(const BIOSLinker *linker, const char *name) > return NULL; > } > > +bool bios_linker_loader_can_write_pointer(void) > +{ > + FWCfgState *fw_cfg = fw_cfg_find(); > + return fw_cfg && fw_cfg_dma_enabled(fw_cfg); > +} > + > /* > * bios_linker_loader_alloc: ask guest to load file into guest memory. > * > diff --git a/hw/acpi/vmgenid.c b/hw/acpi/vmgenid.c > index a32b847fe0..ab5da293fd 100644 > --- a/hw/acpi/vmgenid.c > +++ b/hw/acpi/vmgenid.c > @@ -205,17 +205,11 @@ static void vmgenid_handle_reset(void *opaque) > memset(vms->vmgenid_addr_le, 0, ARRAY_SIZE(vms->vmgenid_addr_le)); > } > > -static Property vmgenid_properties[] = { > - DEFINE_PROP_BOOL("x-write-pointer-available", VmGenIdState, > - write_pointer_available, true), > - DEFINE_PROP_END_OF_LIST(), > -}; > - > static void vmgenid_realize(DeviceState *dev, Error **errp) > { > VmGenIdState *vms = VMGENID(dev); > > - if (!vms->write_pointer_available) { > + if (!bios_linker_loader_can_write_pointer()) { > error_setg(errp, "%s requires DMA write support in fw_cfg, " > "which this machine type does not provide", VMGENID_DEVICE); > return; > @@ -239,7 +233,6 @@ static void vmgenid_device_class_init(ObjectClass *klass, void *data) > dc->vmsd = &vmstate_vmgenid; > dc->realize = vmgenid_realize; > dc->hotpluggable = false; > - dc->props = vmgenid_properties; > > object_class_property_add_str(klass, VMGENID_GUID, NULL, > vmgenid_set_guid, NULL); > -- > 2.13.1.395.gf7b71de06 >
On Thu, Jun 29, 2017 at 03:23:04PM +0200, Marc-André Lureau wrote: > This compat property sole function is to prevent the device from being > instantiated. Instead of requiring an extra compat property, check if > fw_cfg has DMA enabled. > > This has the additional benefit of handling other cases properly, like: > > $ qemu-system-x86_64 -device vmgenid -machine none > qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in fw_cfg, which this machine type does not provide > $ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.9 -global fw_cfg.dma_enabled=off > qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in fw_cfg, which this machine type does not provide > $ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.6 -global fw_cfg.dma_enabled=on > [boots normally] > > Suggested-by: Eduardo Habkost <ehabkost@redhat.com> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
On 06/29/17 15:23, Marc-André Lureau wrote: > This compat property sole function is to prevent the device from being > instantiated. Instead of requiring an extra compat property, check if > fw_cfg has DMA enabled. > > This has the additional benefit of handling other cases properly, like: > > $ qemu-system-x86_64 -device vmgenid -machine none > qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in fw_cfg, which this machine type does not provide > $ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.9 -global fw_cfg.dma_enabled=off > qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in fw_cfg, which this machine type does not provide > $ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.6 -global fw_cfg.dma_enabled=on > [boots normally] > > Suggested-by: Eduardo Habkost <ehabkost@redhat.com> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> > --- > include/hw/acpi/bios-linker-loader.h | 2 ++ > include/hw/compat.h | 4 ---- > hw/acpi/bios-linker-loader.c | 6 ++++++ > hw/acpi/vmgenid.c | 9 +-------- > 4 files changed, 9 insertions(+), 12 deletions(-) > > diff --git a/include/hw/acpi/bios-linker-loader.h b/include/hw/acpi/bios-linker-loader.h > index efe17b0b9c..a711dbced8 100644 > --- a/include/hw/acpi/bios-linker-loader.h > +++ b/include/hw/acpi/bios-linker-loader.h > @@ -7,6 +7,8 @@ typedef struct BIOSLinker { > GArray *file_list; > } BIOSLinker; > > +bool bios_linker_loader_can_write_pointer(void); > + > BIOSLinker *bios_linker_loader_init(void); > > void bios_linker_loader_alloc(BIOSLinker *linker, > diff --git a/include/hw/compat.h b/include/hw/compat.h > index 26cd5851a5..36f02179ac 100644 > --- a/include/hw/compat.h > +++ b/include/hw/compat.h > @@ -150,10 +150,6 @@ > .driver = "fw_cfg_io",\ > .property = "dma_enabled",\ > .value = "off",\ > - },{\ > - .driver = "vmgenid",\ > - .property = "x-write-pointer-available",\ > - .value = "off",\ > }, > > #define HW_COMPAT_2_3 \ > diff --git a/hw/acpi/bios-linker-loader.c b/hw/acpi/bios-linker-loader.c > index 046183a0f1..587d62cb93 100644 > --- a/hw/acpi/bios-linker-loader.c > +++ b/hw/acpi/bios-linker-loader.c > @@ -168,6 +168,12 @@ bios_linker_find_file(const BIOSLinker *linker, const char *name) > return NULL; > } > > +bool bios_linker_loader_can_write_pointer(void) > +{ > + FWCfgState *fw_cfg = fw_cfg_find(); > + return fw_cfg && fw_cfg_dma_enabled(fw_cfg); > +} > + > /* > * bios_linker_loader_alloc: ask guest to load file into guest memory. > * > diff --git a/hw/acpi/vmgenid.c b/hw/acpi/vmgenid.c > index a32b847fe0..ab5da293fd 100644 > --- a/hw/acpi/vmgenid.c > +++ b/hw/acpi/vmgenid.c > @@ -205,17 +205,11 @@ static void vmgenid_handle_reset(void *opaque) > memset(vms->vmgenid_addr_le, 0, ARRAY_SIZE(vms->vmgenid_addr_le)); > } > > -static Property vmgenid_properties[] = { > - DEFINE_PROP_BOOL("x-write-pointer-available", VmGenIdState, > - write_pointer_available, true), > - DEFINE_PROP_END_OF_LIST(), > -}; > - > static void vmgenid_realize(DeviceState *dev, Error **errp) > { > VmGenIdState *vms = VMGENID(dev); > > - if (!vms->write_pointer_available) { > + if (!bios_linker_loader_can_write_pointer()) { > error_setg(errp, "%s requires DMA write support in fw_cfg, " > "which this machine type does not provide", VMGENID_DEVICE); > return; > @@ -239,7 +233,6 @@ static void vmgenid_device_class_init(ObjectClass *klass, void *data) > dc->vmsd = &vmstate_vmgenid; > dc->realize = vmgenid_realize; > dc->hotpluggable = false; > - dc->props = vmgenid_properties; > > object_class_property_add_str(klass, VMGENID_GUID, NULL, > vmgenid_set_guid, NULL); > I believe we discussed this approach back then (but I can't find the relevant messages, of course). What guarantees that, by the time you call fw_cfg_find() from vmgenid_realize() -- that is, from the realize function of an independent device --, the fw_cfg device will have been realized (with its properties having taken their final values)? I don't see how the ordering is guaranteed here; please explain (preferably in the commit message). Thanks, Laszlo
On Thu, Jun 29, 2017 at 03:23:04PM +0200, Marc-André Lureau wrote: > This compat property sole function is to prevent the device from being > instantiated. Instead of requiring an extra compat property, check if > fw_cfg has DMA enabled. > > This has the additional benefit of handling other cases properly, like: > > $ qemu-system-x86_64 -device vmgenid -machine none > qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in fw_cfg, which this machine type does not provide > $ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.9 -global fw_cfg.dma_enabled=off > qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in fw_cfg, which this machine type does not provide > $ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.6 -global fw_cfg.dma_enabled=on > [boots normally] > > Suggested-by: Eduardo Habkost <ehabkost@redhat.com> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Looks like this can go in as a stand-alone patch. I wasn't copied on rest of patchset so I'm not sure who's merging that, but I think this one can be split out. > --- > include/hw/acpi/bios-linker-loader.h | 2 ++ > include/hw/compat.h | 4 ---- > hw/acpi/bios-linker-loader.c | 6 ++++++ > hw/acpi/vmgenid.c | 9 +-------- > 4 files changed, 9 insertions(+), 12 deletions(-) > > diff --git a/include/hw/acpi/bios-linker-loader.h b/include/hw/acpi/bios-linker-loader.h > index efe17b0b9c..a711dbced8 100644 > --- a/include/hw/acpi/bios-linker-loader.h > +++ b/include/hw/acpi/bios-linker-loader.h > @@ -7,6 +7,8 @@ typedef struct BIOSLinker { > GArray *file_list; > } BIOSLinker; > > +bool bios_linker_loader_can_write_pointer(void); > + > BIOSLinker *bios_linker_loader_init(void); > > void bios_linker_loader_alloc(BIOSLinker *linker, > diff --git a/include/hw/compat.h b/include/hw/compat.h > index 26cd5851a5..36f02179ac 100644 > --- a/include/hw/compat.h > +++ b/include/hw/compat.h > @@ -150,10 +150,6 @@ > .driver = "fw_cfg_io",\ > .property = "dma_enabled",\ > .value = "off",\ > - },{\ > - .driver = "vmgenid",\ > - .property = "x-write-pointer-available",\ > - .value = "off",\ > }, > > #define HW_COMPAT_2_3 \ > diff --git a/hw/acpi/bios-linker-loader.c b/hw/acpi/bios-linker-loader.c > index 046183a0f1..587d62cb93 100644 > --- a/hw/acpi/bios-linker-loader.c > +++ b/hw/acpi/bios-linker-loader.c > @@ -168,6 +168,12 @@ bios_linker_find_file(const BIOSLinker *linker, const char *name) > return NULL; > } > > +bool bios_linker_loader_can_write_pointer(void) > +{ > + FWCfgState *fw_cfg = fw_cfg_find(); > + return fw_cfg && fw_cfg_dma_enabled(fw_cfg); > +} > + > /* > * bios_linker_loader_alloc: ask guest to load file into guest memory. > * > diff --git a/hw/acpi/vmgenid.c b/hw/acpi/vmgenid.c > index a32b847fe0..ab5da293fd 100644 > --- a/hw/acpi/vmgenid.c > +++ b/hw/acpi/vmgenid.c > @@ -205,17 +205,11 @@ static void vmgenid_handle_reset(void *opaque) > memset(vms->vmgenid_addr_le, 0, ARRAY_SIZE(vms->vmgenid_addr_le)); > } > > -static Property vmgenid_properties[] = { > - DEFINE_PROP_BOOL("x-write-pointer-available", VmGenIdState, > - write_pointer_available, true), > - DEFINE_PROP_END_OF_LIST(), > -}; > - > static void vmgenid_realize(DeviceState *dev, Error **errp) > { > VmGenIdState *vms = VMGENID(dev); > > - if (!vms->write_pointer_available) { > + if (!bios_linker_loader_can_write_pointer()) { > error_setg(errp, "%s requires DMA write support in fw_cfg, " > "which this machine type does not provide", VMGENID_DEVICE); > return; > @@ -239,7 +233,6 @@ static void vmgenid_device_class_init(ObjectClass *klass, void *data) > dc->vmsd = &vmstate_vmgenid; > dc->realize = vmgenid_realize; > dc->hotpluggable = false; > - dc->props = vmgenid_properties; > > object_class_property_add_str(klass, VMGENID_GUID, NULL, > vmgenid_set_guid, NULL); > -- > 2.13.1.395.gf7b71de06
On Mon, Jul 03, 2017 at 08:06:33PM +0200, Laszlo Ersek wrote: > On 06/29/17 15:23, Marc-André Lureau wrote: > > This compat property sole function is to prevent the device from being > > instantiated. Instead of requiring an extra compat property, check if > > fw_cfg has DMA enabled. > > > > This has the additional benefit of handling other cases properly, like: > > > > $ qemu-system-x86_64 -device vmgenid -machine none > > qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in fw_cfg, which this machine type does not provide > > $ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.9 -global fw_cfg.dma_enabled=off > > qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in fw_cfg, which this machine type does not provide > > $ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.6 -global fw_cfg.dma_enabled=on > > [boots normally] > > > > Suggested-by: Eduardo Habkost <ehabkost@redhat.com> > > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> > > --- > > include/hw/acpi/bios-linker-loader.h | 2 ++ > > include/hw/compat.h | 4 ---- > > hw/acpi/bios-linker-loader.c | 6 ++++++ > > hw/acpi/vmgenid.c | 9 +-------- > > 4 files changed, 9 insertions(+), 12 deletions(-) > > > > diff --git a/include/hw/acpi/bios-linker-loader.h b/include/hw/acpi/bios-linker-loader.h > > index efe17b0b9c..a711dbced8 100644 > > --- a/include/hw/acpi/bios-linker-loader.h > > +++ b/include/hw/acpi/bios-linker-loader.h > > @@ -7,6 +7,8 @@ typedef struct BIOSLinker { > > GArray *file_list; > > } BIOSLinker; > > > > +bool bios_linker_loader_can_write_pointer(void); > > + > > BIOSLinker *bios_linker_loader_init(void); > > > > void bios_linker_loader_alloc(BIOSLinker *linker, > > diff --git a/include/hw/compat.h b/include/hw/compat.h > > index 26cd5851a5..36f02179ac 100644 > > --- a/include/hw/compat.h > > +++ b/include/hw/compat.h > > @@ -150,10 +150,6 @@ > > .driver = "fw_cfg_io",\ > > .property = "dma_enabled",\ > > .value = "off",\ > > - },{\ > > - .driver = "vmgenid",\ > > - .property = "x-write-pointer-available",\ > > - .value = "off",\ > > }, > > > > #define HW_COMPAT_2_3 \ > > diff --git a/hw/acpi/bios-linker-loader.c b/hw/acpi/bios-linker-loader.c > > index 046183a0f1..587d62cb93 100644 > > --- a/hw/acpi/bios-linker-loader.c > > +++ b/hw/acpi/bios-linker-loader.c > > @@ -168,6 +168,12 @@ bios_linker_find_file(const BIOSLinker *linker, const char *name) > > return NULL; > > } > > > > +bool bios_linker_loader_can_write_pointer(void) > > +{ > > + FWCfgState *fw_cfg = fw_cfg_find(); > > + return fw_cfg && fw_cfg_dma_enabled(fw_cfg); > > +} > > + > > /* > > * bios_linker_loader_alloc: ask guest to load file into guest memory. > > * > > diff --git a/hw/acpi/vmgenid.c b/hw/acpi/vmgenid.c > > index a32b847fe0..ab5da293fd 100644 > > --- a/hw/acpi/vmgenid.c > > +++ b/hw/acpi/vmgenid.c > > @@ -205,17 +205,11 @@ static void vmgenid_handle_reset(void *opaque) > > memset(vms->vmgenid_addr_le, 0, ARRAY_SIZE(vms->vmgenid_addr_le)); > > } > > > > -static Property vmgenid_properties[] = { > > - DEFINE_PROP_BOOL("x-write-pointer-available", VmGenIdState, > > - write_pointer_available, true), > > - DEFINE_PROP_END_OF_LIST(), > > -}; > > - > > static void vmgenid_realize(DeviceState *dev, Error **errp) > > { > > VmGenIdState *vms = VMGENID(dev); > > > > - if (!vms->write_pointer_available) { > > + if (!bios_linker_loader_can_write_pointer()) { > > error_setg(errp, "%s requires DMA write support in fw_cfg, " > > "which this machine type does not provide", VMGENID_DEVICE); > > return; > > @@ -239,7 +233,6 @@ static void vmgenid_device_class_init(ObjectClass *klass, void *data) > > dc->vmsd = &vmstate_vmgenid; > > dc->realize = vmgenid_realize; > > dc->hotpluggable = false; > > - dc->props = vmgenid_properties; > > > > object_class_property_add_str(klass, VMGENID_GUID, NULL, > > vmgenid_set_guid, NULL); > > > > I believe we discussed this approach back then (but I can't find the > relevant messages, of course). > > What guarantees that, by the time you call fw_cfg_find() from > vmgenid_realize() -- that is, from the realize function of an > independent device --, the fw_cfg device will have been realized (with > its properties having taken their final values)? I don't see how the > ordering is guaranteed here; please explain (preferably in the commit > message). Good point. What makes this work is the fact that fw_cfg is a built-in device that is initialized very early by the machine init code. We could remove that requirement, but it would require reporting errors from the machine_done notifier (in acpi_setup(), probably). I'm not sure it would be worth the extra complexity. We have at least one other device that also assumes fw_cfg_find() can be safely used on realize: pvpanic.
On 07/03/17 20:27, Eduardo Habkost wrote: > On Mon, Jul 03, 2017 at 08:06:33PM +0200, Laszlo Ersek wrote: >> On 06/29/17 15:23, Marc-André Lureau wrote: >>> This compat property sole function is to prevent the device from being >>> instantiated. Instead of requiring an extra compat property, check if >>> fw_cfg has DMA enabled. >>> >>> This has the additional benefit of handling other cases properly, like: >>> >>> $ qemu-system-x86_64 -device vmgenid -machine none >>> qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in fw_cfg, which this machine type does not provide >>> $ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.9 -global fw_cfg.dma_enabled=off >>> qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in fw_cfg, which this machine type does not provide >>> $ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.6 -global fw_cfg.dma_enabled=on >>> [boots normally] >>> >>> Suggested-by: Eduardo Habkost <ehabkost@redhat.com> >>> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> >>> --- >>> include/hw/acpi/bios-linker-loader.h | 2 ++ >>> include/hw/compat.h | 4 ---- >>> hw/acpi/bios-linker-loader.c | 6 ++++++ >>> hw/acpi/vmgenid.c | 9 +-------- >>> 4 files changed, 9 insertions(+), 12 deletions(-) >>> >>> diff --git a/include/hw/acpi/bios-linker-loader.h b/include/hw/acpi/bios-linker-loader.h >>> index efe17b0b9c..a711dbced8 100644 >>> --- a/include/hw/acpi/bios-linker-loader.h >>> +++ b/include/hw/acpi/bios-linker-loader.h >>> @@ -7,6 +7,8 @@ typedef struct BIOSLinker { >>> GArray *file_list; >>> } BIOSLinker; >>> >>> +bool bios_linker_loader_can_write_pointer(void); >>> + >>> BIOSLinker *bios_linker_loader_init(void); >>> >>> void bios_linker_loader_alloc(BIOSLinker *linker, >>> diff --git a/include/hw/compat.h b/include/hw/compat.h >>> index 26cd5851a5..36f02179ac 100644 >>> --- a/include/hw/compat.h >>> +++ b/include/hw/compat.h >>> @@ -150,10 +150,6 @@ >>> .driver = "fw_cfg_io",\ >>> .property = "dma_enabled",\ >>> .value = "off",\ >>> - },{\ >>> - .driver = "vmgenid",\ >>> - .property = "x-write-pointer-available",\ >>> - .value = "off",\ >>> }, >>> >>> #define HW_COMPAT_2_3 \ >>> diff --git a/hw/acpi/bios-linker-loader.c b/hw/acpi/bios-linker-loader.c >>> index 046183a0f1..587d62cb93 100644 >>> --- a/hw/acpi/bios-linker-loader.c >>> +++ b/hw/acpi/bios-linker-loader.c >>> @@ -168,6 +168,12 @@ bios_linker_find_file(const BIOSLinker *linker, const char *name) >>> return NULL; >>> } >>> >>> +bool bios_linker_loader_can_write_pointer(void) >>> +{ >>> + FWCfgState *fw_cfg = fw_cfg_find(); >>> + return fw_cfg && fw_cfg_dma_enabled(fw_cfg); >>> +} >>> + >>> /* >>> * bios_linker_loader_alloc: ask guest to load file into guest memory. >>> * >>> diff --git a/hw/acpi/vmgenid.c b/hw/acpi/vmgenid.c >>> index a32b847fe0..ab5da293fd 100644 >>> --- a/hw/acpi/vmgenid.c >>> +++ b/hw/acpi/vmgenid.c >>> @@ -205,17 +205,11 @@ static void vmgenid_handle_reset(void *opaque) >>> memset(vms->vmgenid_addr_le, 0, ARRAY_SIZE(vms->vmgenid_addr_le)); >>> } >>> >>> -static Property vmgenid_properties[] = { >>> - DEFINE_PROP_BOOL("x-write-pointer-available", VmGenIdState, >>> - write_pointer_available, true), >>> - DEFINE_PROP_END_OF_LIST(), >>> -}; >>> - >>> static void vmgenid_realize(DeviceState *dev, Error **errp) >>> { >>> VmGenIdState *vms = VMGENID(dev); >>> >>> - if (!vms->write_pointer_available) { >>> + if (!bios_linker_loader_can_write_pointer()) { >>> error_setg(errp, "%s requires DMA write support in fw_cfg, " >>> "which this machine type does not provide", VMGENID_DEVICE); >>> return; >>> @@ -239,7 +233,6 @@ static void vmgenid_device_class_init(ObjectClass *klass, void *data) >>> dc->vmsd = &vmstate_vmgenid; >>> dc->realize = vmgenid_realize; >>> dc->hotpluggable = false; >>> - dc->props = vmgenid_properties; >>> >>> object_class_property_add_str(klass, VMGENID_GUID, NULL, >>> vmgenid_set_guid, NULL); >>> >> >> I believe we discussed this approach back then (but I can't find the >> relevant messages, of course). >> >> What guarantees that, by the time you call fw_cfg_find() from >> vmgenid_realize() -- that is, from the realize function of an >> independent device --, the fw_cfg device will have been realized (with >> its properties having taken their final values)? I don't see how the >> ordering is guaranteed here; please explain (preferably in the commit >> message). > > Good point. What makes this work is the fact that fw_cfg is a built-in > device that is initialized very early by the machine init code. We > could remove that requirement, but it would require reporting errors > from the machine_done notifier (in acpi_setup(), probably). I'm not > sure it would be worth the extra complexity. Thank you for the explanation -- I agree we shouldn't up-end the code now, but I think two sets of documentation should be added: - the commit message should capture your explanation - the bios_linker_loader_can_write_pointer() function should have a reminder that board code must realize fw_cfg first, as a fixed (sysbus?) device, before another device realize function reaches bios_linker_loader_can_write_pointer(). (CC'ing Mark Cave-Ayland for any necessary co-ordination.) > We have at least one other device that also assumes fw_cfg_find() can be > safely used on realize: pvpanic. Good point. Thanks Laszlo
On Thu, Jun 29, 2017 at 03:23:04PM +0200, Marc-André Lureau wrote: > This compat property sole function is to prevent the device from being > instantiated. Instead of requiring an extra compat property, check if > fw_cfg has DMA enabled. > > This has the additional benefit of handling other cases properly, like: > > $ qemu-system-x86_64 -device vmgenid -machine none > qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in fw_cfg, which this machine type does not provide > $ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.9 -global fw_cfg.dma_enabled=off > qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in fw_cfg, which this machine type does not provide > $ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.6 -global fw_cfg.dma_enabled=on > [boots normally] > > Suggested-by: Eduardo Habkost <ehabkost@redhat.com> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> It's a nice cleanup, but I suspect we need to first implement a framework for initialization ordering. I don't much like it that we are adding more dependencies to the current bag of hacks. > --- > include/hw/acpi/bios-linker-loader.h | 2 ++ > include/hw/compat.h | 4 ---- > hw/acpi/bios-linker-loader.c | 6 ++++++ > hw/acpi/vmgenid.c | 9 +-------- > 4 files changed, 9 insertions(+), 12 deletions(-) > > diff --git a/include/hw/acpi/bios-linker-loader.h b/include/hw/acpi/bios-linker-loader.h > index efe17b0b9c..a711dbced8 100644 > --- a/include/hw/acpi/bios-linker-loader.h > +++ b/include/hw/acpi/bios-linker-loader.h > @@ -7,6 +7,8 @@ typedef struct BIOSLinker { > GArray *file_list; > } BIOSLinker; > > +bool bios_linker_loader_can_write_pointer(void); > + > BIOSLinker *bios_linker_loader_init(void); > > void bios_linker_loader_alloc(BIOSLinker *linker, > diff --git a/include/hw/compat.h b/include/hw/compat.h > index 26cd5851a5..36f02179ac 100644 > --- a/include/hw/compat.h > +++ b/include/hw/compat.h > @@ -150,10 +150,6 @@ > .driver = "fw_cfg_io",\ > .property = "dma_enabled",\ > .value = "off",\ > - },{\ > - .driver = "vmgenid",\ > - .property = "x-write-pointer-available",\ > - .value = "off",\ > }, > > #define HW_COMPAT_2_3 \ > diff --git a/hw/acpi/bios-linker-loader.c b/hw/acpi/bios-linker-loader.c > index 046183a0f1..587d62cb93 100644 > --- a/hw/acpi/bios-linker-loader.c > +++ b/hw/acpi/bios-linker-loader.c > @@ -168,6 +168,12 @@ bios_linker_find_file(const BIOSLinker *linker, const char *name) > return NULL; > } > > +bool bios_linker_loader_can_write_pointer(void) > +{ > + FWCfgState *fw_cfg = fw_cfg_find(); > + return fw_cfg && fw_cfg_dma_enabled(fw_cfg); > +} > + > /* > * bios_linker_loader_alloc: ask guest to load file into guest memory. > * > diff --git a/hw/acpi/vmgenid.c b/hw/acpi/vmgenid.c > index a32b847fe0..ab5da293fd 100644 > --- a/hw/acpi/vmgenid.c > +++ b/hw/acpi/vmgenid.c > @@ -205,17 +205,11 @@ static void vmgenid_handle_reset(void *opaque) > memset(vms->vmgenid_addr_le, 0, ARRAY_SIZE(vms->vmgenid_addr_le)); > } > > -static Property vmgenid_properties[] = { > - DEFINE_PROP_BOOL("x-write-pointer-available", VmGenIdState, > - write_pointer_available, true), > - DEFINE_PROP_END_OF_LIST(), > -}; > - > static void vmgenid_realize(DeviceState *dev, Error **errp) > { > VmGenIdState *vms = VMGENID(dev); > > - if (!vms->write_pointer_available) { > + if (!bios_linker_loader_can_write_pointer()) { > error_setg(errp, "%s requires DMA write support in fw_cfg, " > "which this machine type does not provide", VMGENID_DEVICE); > return; > @@ -239,7 +233,6 @@ static void vmgenid_device_class_init(ObjectClass *klass, void *data) > dc->vmsd = &vmstate_vmgenid; > dc->realize = vmgenid_realize; > dc->hotpluggable = false; > - dc->props = vmgenid_properties; > > object_class_property_add_str(klass, VMGENID_GUID, NULL, > vmgenid_set_guid, NULL); > -- > 2.13.1.395.gf7b71de06
On Mon, Jul 03, 2017 at 09:38:52PM +0300, Michael S. Tsirkin wrote: > On Thu, Jun 29, 2017 at 03:23:04PM +0200, Marc-André Lureau wrote: > > This compat property sole function is to prevent the device from being > > instantiated. Instead of requiring an extra compat property, check if > > fw_cfg has DMA enabled. > > > > This has the additional benefit of handling other cases properly, like: > > > > $ qemu-system-x86_64 -device vmgenid -machine none > > qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in fw_cfg, which this machine type does not provide > > $ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.9 -global fw_cfg.dma_enabled=off > > qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in fw_cfg, which this machine type does not provide > > $ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.6 -global fw_cfg.dma_enabled=on > > [boots normally] > > > > Suggested-by: Eduardo Habkost <ehabkost@redhat.com> > > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> > > It's a nice cleanup, but I suspect we need to first implement > a framework for initialization ordering. I don't much like it > that we are adding more dependencies to the current bag of hacks. I agree we should address this, but in this case there's no need to introduce new mechanisms for initialization ordering if we just check the dependencies on machine_done notifier or acpi_setup() (which is called by machine_done).
On Mon, Jul 03, 2017 at 03:50:52PM -0300, Eduardo Habkost wrote: > On Mon, Jul 03, 2017 at 09:38:52PM +0300, Michael S. Tsirkin wrote: > > On Thu, Jun 29, 2017 at 03:23:04PM +0200, Marc-André Lureau wrote: > > > This compat property sole function is to prevent the device from being > > > instantiated. Instead of requiring an extra compat property, check if > > > fw_cfg has DMA enabled. > > > > > > This has the additional benefit of handling other cases properly, like: > > > > > > $ qemu-system-x86_64 -device vmgenid -machine none > > > qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in fw_cfg, which this machine type does not provide > > > $ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.9 -global fw_cfg.dma_enabled=off > > > qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in fw_cfg, which this machine type does not provide > > > $ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.6 -global fw_cfg.dma_enabled=on > > > [boots normally] > > > > > > Suggested-by: Eduardo Habkost <ehabkost@redhat.com> > > > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> > > > > It's a nice cleanup, but I suspect we need to first implement > > a framework for initialization ordering. I don't much like it > > that we are adding more dependencies to the current bag of hacks. > > I agree we should address this, but in this case there's no need to > introduce new mechanisms for initialization ordering if we just check > the dependencies on machine_done notifier or acpi_setup() (which is > called by machine_done). I guess what should fail is attempt to register a writeable blob. This sounds reasonable. > -- > Eduardo
diff --git a/include/hw/acpi/bios-linker-loader.h b/include/hw/acpi/bios-linker-loader.h index efe17b0b9c..a711dbced8 100644 --- a/include/hw/acpi/bios-linker-loader.h +++ b/include/hw/acpi/bios-linker-loader.h @@ -7,6 +7,8 @@ typedef struct BIOSLinker { GArray *file_list; } BIOSLinker; +bool bios_linker_loader_can_write_pointer(void); + BIOSLinker *bios_linker_loader_init(void); void bios_linker_loader_alloc(BIOSLinker *linker, diff --git a/include/hw/compat.h b/include/hw/compat.h index 26cd5851a5..36f02179ac 100644 --- a/include/hw/compat.h +++ b/include/hw/compat.h @@ -150,10 +150,6 @@ .driver = "fw_cfg_io",\ .property = "dma_enabled",\ .value = "off",\ - },{\ - .driver = "vmgenid",\ - .property = "x-write-pointer-available",\ - .value = "off",\ }, #define HW_COMPAT_2_3 \ diff --git a/hw/acpi/bios-linker-loader.c b/hw/acpi/bios-linker-loader.c index 046183a0f1..587d62cb93 100644 --- a/hw/acpi/bios-linker-loader.c +++ b/hw/acpi/bios-linker-loader.c @@ -168,6 +168,12 @@ bios_linker_find_file(const BIOSLinker *linker, const char *name) return NULL; } +bool bios_linker_loader_can_write_pointer(void) +{ + FWCfgState *fw_cfg = fw_cfg_find(); + return fw_cfg && fw_cfg_dma_enabled(fw_cfg); +} + /* * bios_linker_loader_alloc: ask guest to load file into guest memory. * diff --git a/hw/acpi/vmgenid.c b/hw/acpi/vmgenid.c index a32b847fe0..ab5da293fd 100644 --- a/hw/acpi/vmgenid.c +++ b/hw/acpi/vmgenid.c @@ -205,17 +205,11 @@ static void vmgenid_handle_reset(void *opaque) memset(vms->vmgenid_addr_le, 0, ARRAY_SIZE(vms->vmgenid_addr_le)); } -static Property vmgenid_properties[] = { - DEFINE_PROP_BOOL("x-write-pointer-available", VmGenIdState, - write_pointer_available, true), - DEFINE_PROP_END_OF_LIST(), -}; - static void vmgenid_realize(DeviceState *dev, Error **errp) { VmGenIdState *vms = VMGENID(dev); - if (!vms->write_pointer_available) { + if (!bios_linker_loader_can_write_pointer()) { error_setg(errp, "%s requires DMA write support in fw_cfg, " "which this machine type does not provide", VMGENID_DEVICE); return; @@ -239,7 +233,6 @@ static void vmgenid_device_class_init(ObjectClass *klass, void *data) dc->vmsd = &vmstate_vmgenid; dc->realize = vmgenid_realize; dc->hotpluggable = false; - dc->props = vmgenid_properties; object_class_property_add_str(klass, VMGENID_GUID, NULL, vmgenid_set_guid, NULL);
This compat property sole function is to prevent the device from being instantiated. Instead of requiring an extra compat property, check if fw_cfg has DMA enabled. This has the additional benefit of handling other cases properly, like: $ qemu-system-x86_64 -device vmgenid -machine none qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in fw_cfg, which this machine type does not provide $ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.9 -global fw_cfg.dma_enabled=off qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in fw_cfg, which this machine type does not provide $ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.6 -global fw_cfg.dma_enabled=on [boots normally] Suggested-by: Eduardo Habkost <ehabkost@redhat.com> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> --- include/hw/acpi/bios-linker-loader.h | 2 ++ include/hw/compat.h | 4 ---- hw/acpi/bios-linker-loader.c | 6 ++++++ hw/acpi/vmgenid.c | 9 +-------- 4 files changed, 9 insertions(+), 12 deletions(-)