| Message ID | 20200817033729.10848-3-zhukeqian1@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: Some fixes and code adjustments for pvtime ST | expand |
On 2020-08-17 04:37, Keqian Zhu wrote: > ARM64 PV-time ST is configured by userspace through vCPU attribute, > and KVM_DEV_TYPE_ARM_PV_TIME is unused. > > Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com> > --- > include/uapi/linux/kvm.h | 2 -- > tools/include/uapi/linux/kvm.h | 2 -- > 2 files changed, 4 deletions(-) > > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > index 4fdf303..9a6b97e 100644 > --- a/include/uapi/linux/kvm.h > +++ b/include/uapi/linux/kvm.h > @@ -1258,8 +1258,6 @@ enum kvm_device_type { > #define KVM_DEV_TYPE_ARM_VGIC_ITS KVM_DEV_TYPE_ARM_VGIC_ITS > KVM_DEV_TYPE_XIVE, > #define KVM_DEV_TYPE_XIVE KVM_DEV_TYPE_XIVE > - KVM_DEV_TYPE_ARM_PV_TIME, > -#define KVM_DEV_TYPE_ARM_PV_TIME KVM_DEV_TYPE_ARM_PV_TIME > KVM_DEV_TYPE_MAX, > }; > > diff --git a/tools/include/uapi/linux/kvm.h > b/tools/include/uapi/linux/kvm.h > index 4fdf303..9a6b97e 100644 > --- a/tools/include/uapi/linux/kvm.h > +++ b/tools/include/uapi/linux/kvm.h > @@ -1258,8 +1258,6 @@ enum kvm_device_type { > #define KVM_DEV_TYPE_ARM_VGIC_ITS KVM_DEV_TYPE_ARM_VGIC_ITS > KVM_DEV_TYPE_XIVE, > #define KVM_DEV_TYPE_XIVE KVM_DEV_TYPE_XIVE > - KVM_DEV_TYPE_ARM_PV_TIME, > -#define KVM_DEV_TYPE_ARM_PV_TIME KVM_DEV_TYPE_ARM_PV_TIME > KVM_DEV_TYPE_MAX, > }; No. You can't drop anything from UAPI, used or not. Doing so will break the compilation of any userspace that, for any reason, references this value. We cannot reuse this value in the future either, as it would create a we wouldn't know which device to create. It is pretty unfortunate that PV time has turned into such a train wreck, but that's what we have now, and it has to stay. M.
Hi Marc, On 2020/8/17 15:39, Marc Zyngier wrote: > On 2020-08-17 04:37, Keqian Zhu wrote: >> ARM64 PV-time ST is configured by userspace through vCPU attribute, >> and KVM_DEV_TYPE_ARM_PV_TIME is unused. >> >> Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com> >> --- >> include/uapi/linux/kvm.h | 2 -- >> tools/include/uapi/linux/kvm.h | 2 -- >> 2 files changed, 4 deletions(-) >> >> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h >> index 4fdf303..9a6b97e 100644 >> --- a/include/uapi/linux/kvm.h >> +++ b/include/uapi/linux/kvm.h >> @@ -1258,8 +1258,6 @@ enum kvm_device_type { >> #define KVM_DEV_TYPE_ARM_VGIC_ITS KVM_DEV_TYPE_ARM_VGIC_ITS >> KVM_DEV_TYPE_XIVE, >> #define KVM_DEV_TYPE_XIVE KVM_DEV_TYPE_XIVE >> - KVM_DEV_TYPE_ARM_PV_TIME, >> -#define KVM_DEV_TYPE_ARM_PV_TIME KVM_DEV_TYPE_ARM_PV_TIME >> KVM_DEV_TYPE_MAX, >> }; >> >> diff --git a/tools/include/uapi/linux/kvm.h b/tools/include/uapi/linux/kvm.h >> index 4fdf303..9a6b97e 100644 >> --- a/tools/include/uapi/linux/kvm.h >> +++ b/tools/include/uapi/linux/kvm.h >> @@ -1258,8 +1258,6 @@ enum kvm_device_type { >> #define KVM_DEV_TYPE_ARM_VGIC_ITS KVM_DEV_TYPE_ARM_VGIC_ITS >> KVM_DEV_TYPE_XIVE, >> #define KVM_DEV_TYPE_XIVE KVM_DEV_TYPE_XIVE >> - KVM_DEV_TYPE_ARM_PV_TIME, >> -#define KVM_DEV_TYPE_ARM_PV_TIME KVM_DEV_TYPE_ARM_PV_TIME >> KVM_DEV_TYPE_MAX, >> }; > > No. You can't drop anything from UAPI, used or not. Doing so will > break the compilation of any userspace that, for any reason, references > this value. We cannot reuse this value in the future either, as it would > create a we wouldn't know which device to create. > > It is pretty unfortunate that PV time has turned into such a train wreck, > but that's what we have now, and it has to stay. Well, I see. It is a sad thing indeed. Thanks, Keqian
On 17/08/2020 09:43, zhukeqian wrote: > Hi Marc, > > On 2020/8/17 15:39, Marc Zyngier wrote: >> On 2020-08-17 04:37, Keqian Zhu wrote: >>> ARM64 PV-time ST is configured by userspace through vCPU attribute, >>> and KVM_DEV_TYPE_ARM_PV_TIME is unused. >>> >>> Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com> >>> --- >>> include/uapi/linux/kvm.h | 2 -- >>> tools/include/uapi/linux/kvm.h | 2 -- >>> 2 files changed, 4 deletions(-) >>> >>> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h >>> index 4fdf303..9a6b97e 100644 >>> --- a/include/uapi/linux/kvm.h >>> +++ b/include/uapi/linux/kvm.h >>> @@ -1258,8 +1258,6 @@ enum kvm_device_type { >>> #define KVM_DEV_TYPE_ARM_VGIC_ITS KVM_DEV_TYPE_ARM_VGIC_ITS >>> KVM_DEV_TYPE_XIVE, >>> #define KVM_DEV_TYPE_XIVE KVM_DEV_TYPE_XIVE >>> - KVM_DEV_TYPE_ARM_PV_TIME, >>> -#define KVM_DEV_TYPE_ARM_PV_TIME KVM_DEV_TYPE_ARM_PV_TIME >>> KVM_DEV_TYPE_MAX, >>> }; >>> >>> diff --git a/tools/include/uapi/linux/kvm.h b/tools/include/uapi/linux/kvm.h >>> index 4fdf303..9a6b97e 100644 >>> --- a/tools/include/uapi/linux/kvm.h >>> +++ b/tools/include/uapi/linux/kvm.h >>> @@ -1258,8 +1258,6 @@ enum kvm_device_type { >>> #define KVM_DEV_TYPE_ARM_VGIC_ITS KVM_DEV_TYPE_ARM_VGIC_ITS >>> KVM_DEV_TYPE_XIVE, >>> #define KVM_DEV_TYPE_XIVE KVM_DEV_TYPE_XIVE >>> - KVM_DEV_TYPE_ARM_PV_TIME, >>> -#define KVM_DEV_TYPE_ARM_PV_TIME KVM_DEV_TYPE_ARM_PV_TIME >>> KVM_DEV_TYPE_MAX, >>> }; >> >> No. You can't drop anything from UAPI, used or not. Doing so will >> break the compilation of any userspace that, for any reason, references >> this value. We cannot reuse this value in the future either, as it would >> create a we wouldn't know which device to create. >> >> It is pretty unfortunate that PV time has turned into such a train wreck, >> but that's what we have now, and it has to stay. > Well, I see. It is a sad thing indeed. Sorry about that, this got refactored so many times I guess I lost track of what was actually needed and this hunk remained when it should have been removed. I would hope that I'm the only one who has any userspace code which uses this, but I guess we should still be cautious since this has been in several releases now. Steve
Hi Steven, On 2020/8/17 17:49, Steven Price wrote: > On 17/08/2020 09:43, zhukeqian wrote: >> Hi Marc, >> [...] >>> >>> It is pretty unfortunate that PV time has turned into such a train wreck, >>> but that's what we have now, and it has to stay. >> Well, I see. It is a sad thing indeed. > > Sorry about that, this got refactored so many times I guess I lost track of what was actually needed and this hunk remained when it should have been removed. > It's fine :-) , not a serious problem. > I would hope that I'm the only one who has any userspace code which uses this, but I guess we should still be cautious since this has been in several releases now. > OK. For insurance purposes, we ought to ignore this patch to avoid breaking any user-space program. > Steve > . Thanks, Keqian >
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 4fdf303..9a6b97e 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1258,8 +1258,6 @@ enum kvm_device_type { #define KVM_DEV_TYPE_ARM_VGIC_ITS KVM_DEV_TYPE_ARM_VGIC_ITS KVM_DEV_TYPE_XIVE, #define KVM_DEV_TYPE_XIVE KVM_DEV_TYPE_XIVE - KVM_DEV_TYPE_ARM_PV_TIME, -#define KVM_DEV_TYPE_ARM_PV_TIME KVM_DEV_TYPE_ARM_PV_TIME KVM_DEV_TYPE_MAX, }; diff --git a/tools/include/uapi/linux/kvm.h b/tools/include/uapi/linux/kvm.h index 4fdf303..9a6b97e 100644 --- a/tools/include/uapi/linux/kvm.h +++ b/tools/include/uapi/linux/kvm.h @@ -1258,8 +1258,6 @@ enum kvm_device_type { #define KVM_DEV_TYPE_ARM_VGIC_ITS KVM_DEV_TYPE_ARM_VGIC_ITS KVM_DEV_TYPE_XIVE, #define KVM_DEV_TYPE_XIVE KVM_DEV_TYPE_XIVE - KVM_DEV_TYPE_ARM_PV_TIME, -#define KVM_DEV_TYPE_ARM_PV_TIME KVM_DEV_TYPE_ARM_PV_TIME KVM_DEV_TYPE_MAX, };
ARM64 PV-time ST is configured by userspace through vCPU attribute, and KVM_DEV_TYPE_ARM_PV_TIME is unused. Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com> --- include/uapi/linux/kvm.h | 2 -- tools/include/uapi/linux/kvm.h | 2 -- 2 files changed, 4 deletions(-)