| Message ID | 20201105124353.3680057-2-philmd@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | hw/virtio: Allow to disable legacy VIRTIO | expand |
On Thu, 5 Nov 2020 13:43:51 +0100 Philippe Mathieu-Daudé <philmd@redhat.com> wrote: > Per [1] (Terminology): > > Legacy interfaces are not required; ie. don’t implement them > unless you have a need for backwards compatibility! > > [2] (Version 1.0): > > The device configuration space uses the little-endian format > for multi-byte fields. > > and [3] (Legacy Interface): > > for legacy interfaces, device configuration space is generally > the guest’s native endian, rather than PCI’s little-endian. > The correct endian-ness is documented for each device. > > Add the --disable-virtio-legacy configure flag to produce builds > with VIRTIO 1.0 only, and the --enable-virtio-legacy to include > legacy VIRTIO support (supporting legacy VIRTIO is the default). This is only dealing with endianess issues; there are other differences on the control plane as well. Currently, virtio-pci has the option to make devices non-transitional, but virtio-ccw has not (only for device types). For virtio-mmio, you need to select one of legacy or non-transitional, IIRC. > > [1] http://docs.oasis-open.org/virtio/virtio/v1.0/cs04/virtio-v1.0-cs04.html#x1-60001 > [2] http://docs.oasis-open.org/virtio/virtio/v1.0/cs04/virtio-v1.0-cs04.html#x1-170003 > [3] http://docs.oasis-open.org/virtio/virtio/v1.0/cs04/virtio-v1.0-cs04.html#x1-200003 > > Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> > --- > configure | 10 ++++++++++ > meson.build | 1 + > include/hw/virtio/virtio-access.h | 19 +++++-------------- > hw/virtio/virtio-legacy.c | 29 +++++++++++++++++++++++++++++ > hw/virtio/meson.build | 1 + > 5 files changed, 46 insertions(+), 14 deletions(-) > create mode 100644 hw/virtio/virtio-legacy.c (...) > diff --git a/include/hw/virtio/virtio-access.h b/include/hw/virtio/virtio-access.h > index 6818a23a2d3..b6c060f8cc6 100644 > --- a/include/hw/virtio/virtio-access.h > +++ b/include/hw/virtio/virtio-access.h > @@ -20,24 +20,15 @@ > #include "hw/virtio/virtio.h" > #include "hw/virtio/virtio-bus.h" > > -#if defined(TARGET_PPC64) || defined(TARGET_ARM) > -#define LEGACY_VIRTIO_IS_BIENDIAN 1 > -#endif > - > +#ifdef CONFIG_VIRTIO_LEGACY > +bool virtio_access_is_big_endian(VirtIODevice *vdev); > +#else > static inline bool virtio_access_is_big_endian(VirtIODevice *vdev) > { > -#if defined(LEGACY_VIRTIO_IS_BIENDIAN) > - return virtio_is_big_endian(vdev); > -#elif defined(TARGET_WORDS_BIGENDIAN) > - if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { > - /* Devices conforming to VIRTIO 1.0 or later are always LE. */ > - return false; > - } > - return true; > -#else > + /* Devices conforming to VIRTIO 1.0 or later are always LE. */ > return false; This will make migration from a QEMU that has devices for which 1.0 has not been negotiated fail. > -#endif > } > +#endif > > static inline uint16_t virtio_lduw_phys(VirtIODevice *vdev, hwaddr pa) > {
On 05/11/20 13:43, Philippe Mathieu-Daudé wrote: > +virtio_legacy="enabled" > virtiofsd="auto" > virtfs="" > libudev="auto" > @@ -1001,6 +1002,10 @@ for opt do > ;; > --enable-libudev) libudev="enabled" > ;; > + --disable-virtio-legacy) virtio_legacy="disabled" > + ;; > + --enable-virtio-legacy) virtio_legacy="enabled" > + ;; > --disable-virtiofsd) virtiofsd="disabled" > ;; > --enable-virtiofsd) virtiofsd="enabled" > @@ -1764,6 +1769,7 @@ disabled with --disable-FEATURE, default is enabled if available: > vnc-png PNG compression for VNC server > cocoa Cocoa UI (Mac OS X only) > virtfs VirtFS > + virtio-legacy enable support for legacy virtio (before VIRTIO 1.0) > virtiofsd build virtiofs daemon (virtiofsd) > libudev Use libudev to enumerate host devices > mpath Multipath persistent reservation passthrough > @@ -6816,6 +6822,10 @@ if test "$safe_stack" = "yes"; then > echo "CONFIG_SAFESTACK=y" >> $config_host_mak > fi > > +if test "$virtio_legacy" = "enabled"; then > + echo "CONFIG_VIRTIO_LEGACY=y" >> $config_host_mak > +fi Please use meson_options.txt instead (you can make it a boolean option with true/false as the choices for the shell variable). Paolo > # If we're using a separate build tree, set it up now. > # DIRS are directories which we simply mkdir in the build tree; > # LINKS are things to symlink back into the source tree > diff --git a/meson.build b/meson.build > index 39ac5cf6d8a..51406c28c6e 100644 > --- a/meson.build > +++ b/meson.build > @@ -2061,6 +2061,7 @@ > summary_info += {'Block whitelist (rw)': config_host['CONFIG_BDRV_RW_WHITELIST']} > summary_info += {'Block whitelist (ro)': config_host['CONFIG_BDRV_RO_WHITELIST']} > summary_info += {'VirtFS support': config_host.has_key('CONFIG_VIRTFS')} > +summary_info += {'Legacy VIRTIO support': config_host.has_key('CONFIG_VIRTIO_LEGACY')}
On 11/5/20 2:06 PM, Cornelia Huck wrote: > On Thu, 5 Nov 2020 13:43:51 +0100 > Philippe Mathieu-Daudé <philmd@redhat.com> wrote: > >> Per [1] (Terminology): >> >> Legacy interfaces are not required; ie. don’t implement them >> unless you have a need for backwards compatibility! >> >> [2] (Version 1.0): >> >> The device configuration space uses the little-endian format >> for multi-byte fields. >> >> and [3] (Legacy Interface): >> >> for legacy interfaces, device configuration space is generally >> the guest’s native endian, rather than PCI’s little-endian. >> The correct endian-ness is documented for each device. >> >> Add the --disable-virtio-legacy configure flag to produce builds >> with VIRTIO 1.0 only, and the --enable-virtio-legacy to include >> legacy VIRTIO support (supporting legacy VIRTIO is the default). > > This is only dealing with endianess issues; there are other differences > on the control plane as well. > > Currently, virtio-pci has the option to make devices non-transitional, > but virtio-ccw has not (only for device types). For virtio-mmio, you > need to select one of legacy or non-transitional, IIRC. > >> >> [1] http://docs.oasis-open.org/virtio/virtio/v1.0/cs04/virtio-v1.0-cs04.html#x1-60001 >> [2] http://docs.oasis-open.org/virtio/virtio/v1.0/cs04/virtio-v1.0-cs04.html#x1-170003 >> [3] http://docs.oasis-open.org/virtio/virtio/v1.0/cs04/virtio-v1.0-cs04.html#x1-200003 >> >> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> >> --- >> configure | 10 ++++++++++ >> meson.build | 1 + >> include/hw/virtio/virtio-access.h | 19 +++++-------------- >> hw/virtio/virtio-legacy.c | 29 +++++++++++++++++++++++++++++ >> hw/virtio/meson.build | 1 + >> 5 files changed, 46 insertions(+), 14 deletions(-) >> create mode 100644 hw/virtio/virtio-legacy.c > > (...) > >> diff --git a/include/hw/virtio/virtio-access.h b/include/hw/virtio/virtio-access.h >> index 6818a23a2d3..b6c060f8cc6 100644 >> --- a/include/hw/virtio/virtio-access.h >> +++ b/include/hw/virtio/virtio-access.h >> @@ -20,24 +20,15 @@ >> #include "hw/virtio/virtio.h" >> #include "hw/virtio/virtio-bus.h" >> >> -#if defined(TARGET_PPC64) || defined(TARGET_ARM) >> -#define LEGACY_VIRTIO_IS_BIENDIAN 1 >> -#endif >> - >> +#ifdef CONFIG_VIRTIO_LEGACY >> +bool virtio_access_is_big_endian(VirtIODevice *vdev); >> +#else >> static inline bool virtio_access_is_big_endian(VirtIODevice *vdev) >> { >> -#if defined(LEGACY_VIRTIO_IS_BIENDIAN) >> - return virtio_is_big_endian(vdev); >> -#elif defined(TARGET_WORDS_BIGENDIAN) >> - if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { >> - /* Devices conforming to VIRTIO 1.0 or later are always LE. */ >> - return false; >> - } >> - return true; >> -#else >> + /* Devices conforming to VIRTIO 1.0 or later are always LE. */ >> return false; > > This will make migration from a QEMU that has devices for which 1.0 has > not been negotiated fail. Oh good point... Not as easy as I thought then :/ Now I'm seeing plenty of possible problems. Commits 9b3a35ec823 & d55f518248f help a bit: ("virtio: verify that legacy support is not accidentally on") ("virtio: skip legacy support check on machine types less than 5.1") Thanks for warning :) > >> -#endif >> } >> +#endif >> >> static inline uint16_t virtio_lduw_phys(VirtIODevice *vdev, hwaddr pa) >> { >
diff --git a/configure b/configure index 2c3c69f1188..f46216b3788 100755 --- a/configure +++ b/configure @@ -302,6 +302,7 @@ fdt="auto" netmap="no" sdl="auto" sdl_image="auto" +virtio_legacy="enabled" virtiofsd="auto" virtfs="" libudev="auto" @@ -1001,6 +1002,10 @@ for opt do ;; --enable-libudev) libudev="enabled" ;; + --disable-virtio-legacy) virtio_legacy="disabled" + ;; + --enable-virtio-legacy) virtio_legacy="enabled" + ;; --disable-virtiofsd) virtiofsd="disabled" ;; --enable-virtiofsd) virtiofsd="enabled" @@ -1764,6 +1769,7 @@ disabled with --disable-FEATURE, default is enabled if available: vnc-png PNG compression for VNC server cocoa Cocoa UI (Mac OS X only) virtfs VirtFS + virtio-legacy enable support for legacy virtio (before VIRTIO 1.0) virtiofsd build virtiofs daemon (virtiofsd) libudev Use libudev to enumerate host devices mpath Multipath persistent reservation passthrough @@ -6816,6 +6822,10 @@ if test "$safe_stack" = "yes"; then echo "CONFIG_SAFESTACK=y" >> $config_host_mak fi +if test "$virtio_legacy" = "enabled"; then + echo "CONFIG_VIRTIO_LEGACY=y" >> $config_host_mak +fi + # If we're using a separate build tree, set it up now. # DIRS are directories which we simply mkdir in the build tree; # LINKS are things to symlink back into the source tree diff --git a/meson.build b/meson.build index 39ac5cf6d8a..51406c28c6e 100644 --- a/meson.build +++ b/meson.build @@ -2061,6 +2061,7 @@ summary_info += {'Block whitelist (rw)': config_host['CONFIG_BDRV_RW_WHITELIST']} summary_info += {'Block whitelist (ro)': config_host['CONFIG_BDRV_RO_WHITELIST']} summary_info += {'VirtFS support': config_host.has_key('CONFIG_VIRTFS')} +summary_info += {'Legacy VIRTIO support': config_host.has_key('CONFIG_VIRTIO_LEGACY')} summary_info += {'build virtiofs daemon': have_virtiofsd} summary_info += {'Multipath support': mpathpersist.found()} summary_info += {'VNC support': vnc.found()} diff --git a/include/hw/virtio/virtio-access.h b/include/hw/virtio/virtio-access.h index 6818a23a2d3..b6c060f8cc6 100644 --- a/include/hw/virtio/virtio-access.h +++ b/include/hw/virtio/virtio-access.h @@ -20,24 +20,15 @@ #include "hw/virtio/virtio.h" #include "hw/virtio/virtio-bus.h" -#if defined(TARGET_PPC64) || defined(TARGET_ARM) -#define LEGACY_VIRTIO_IS_BIENDIAN 1 -#endif - +#ifdef CONFIG_VIRTIO_LEGACY +bool virtio_access_is_big_endian(VirtIODevice *vdev); +#else static inline bool virtio_access_is_big_endian(VirtIODevice *vdev) { -#if defined(LEGACY_VIRTIO_IS_BIENDIAN) - return virtio_is_big_endian(vdev); -#elif defined(TARGET_WORDS_BIGENDIAN) - if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { - /* Devices conforming to VIRTIO 1.0 or later are always LE. */ - return false; - } - return true; -#else + /* Devices conforming to VIRTIO 1.0 or later are always LE. */ return false; -#endif } +#endif static inline uint16_t virtio_lduw_phys(VirtIODevice *vdev, hwaddr pa) { diff --git a/hw/virtio/virtio-legacy.c b/hw/virtio/virtio-legacy.c new file mode 100644 index 00000000000..bf28c824a25 --- /dev/null +++ b/hw/virtio/virtio-legacy.c @@ -0,0 +1,29 @@ +/* + * Legacy virtio endian helpers. + * + * Copyright Red Hat, Inc. 2020 + * + * SPDX-License-Identifier: GPL-2.0-or-later + */ +#include "qemu/osdep.h" +#include "hw/virtio/virtio.h" +#include "hw/virtio/virtio-access.h" + +#if defined(TARGET_PPC64) || defined(TARGET_ARM) +# define LEGACY_VIRTIO_IS_BIENDIAN 1 +#endif + +bool virtio_access_is_big_endian(VirtIODevice *vdev) +{ +#if defined(LEGACY_VIRTIO_IS_BIENDIAN) + return virtio_is_big_endian(vdev); +#elif defined(TARGET_WORDS_BIGENDIAN) + if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { + /* Devices conforming to VIRTIO 1.0 or later are always LE. */ + return false; + } + return true; +#else + return false; +#endif +} diff --git a/hw/virtio/meson.build b/hw/virtio/meson.build index fbff9bc9d4d..95415913a9a 100644 --- a/hw/virtio/meson.build +++ b/hw/virtio/meson.build @@ -11,6 +11,7 @@ virtio_ss = ss.source_set() virtio_ss.add(files('virtio.c')) +virtio_ss.add(when: 'CONFIG_VIRTIO_LEGACY', if_true: files('virtio-legacy.c')) virtio_ss.add(when: 'CONFIG_VHOST', if_true: files('vhost.c', 'vhost-backend.c')) virtio_ss.add(when: 'CONFIG_VHOST_USER', if_true: files('vhost-user.c')) virtio_ss.add(when: 'CONFIG_VHOST_VDPA', if_true: files('vhost-vdpa.c'))
Per [1] (Terminology): Legacy interfaces are not required; ie. don’t implement them unless you have a need for backwards compatibility! [2] (Version 1.0): The device configuration space uses the little-endian format for multi-byte fields. and [3] (Legacy Interface): for legacy interfaces, device configuration space is generally the guest’s native endian, rather than PCI’s little-endian. The correct endian-ness is documented for each device. Add the --disable-virtio-legacy configure flag to produce builds with VIRTIO 1.0 only, and the --enable-virtio-legacy to include legacy VIRTIO support (supporting legacy VIRTIO is the default). [1] http://docs.oasis-open.org/virtio/virtio/v1.0/cs04/virtio-v1.0-cs04.html#x1-60001 [2] http://docs.oasis-open.org/virtio/virtio/v1.0/cs04/virtio-v1.0-cs04.html#x1-170003 [3] http://docs.oasis-open.org/virtio/virtio/v1.0/cs04/virtio-v1.0-cs04.html#x1-200003 Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> --- configure | 10 ++++++++++ meson.build | 1 + include/hw/virtio/virtio-access.h | 19 +++++-------------- hw/virtio/virtio-legacy.c | 29 +++++++++++++++++++++++++++++ hw/virtio/meson.build | 1 + 5 files changed, 46 insertions(+), 14 deletions(-) create mode 100644 hw/virtio/virtio-legacy.c