| Message ID | 20180919084802.183381-15-frankja@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: s390: Huge page splitting and shadowing | expand |
Am 19.09.18 um 10:48 schrieb Janosch Frank: > Now that we have VSIE support for VMs with huge memory backing, let's > make both features usable at the same time. > > Signed-off-by: Janosch Frank <frankja@linux.ibm.com> > --- > Documentation/virtual/kvm/api.txt | 7 +++---- > arch/s390/kvm/kvm-s390.c | 14 ++------------ > arch/s390/mm/gmap.c | 1 - > 3 files changed, 5 insertions(+), 17 deletions(-) > > diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt > index 8d8a372c8340..9ec6d23f41d5 100644 > --- a/Documentation/virtual/kvm/api.txt > +++ b/Documentation/virtual/kvm/api.txt > @@ -4509,15 +4509,14 @@ Do not enable KVM_FEATURE_PV_UNHALT if you disable HLT exits. > > Architectures: s390 > Parameters: none > -Returns: 0 on success, -EINVAL if hpage module parameter was not set > - or cmma is enabled, or the VM has the KVM_VM_S390_UCONTROL > +Returns: 0 on success, -EINVAL if cmma is enabled, or the VM has the KVM_VM_S390_UCONTROL > flag set > > With this capability the KVM support for memory backing with 1m pages > through hugetlbfs can be enabled for a VM. After the capability is > enabled, cmma can't be enabled anymore and pfmfi and the storage key > -interpretation are disabled. If cmma has already been enabled or the > -hpage module parameter is not set to 1, -EINVAL is returned. > +interpretation are disabled. If cmma has already been enabled, -EINVAL > +is returned. > > While it is generally possible to create a huge page backed VM without > this capability, the VM will not be able to run. > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > index ac5da6b0b862..59f53b7c72d6 100644 > --- a/arch/s390/kvm/kvm-s390.c > +++ b/arch/s390/kvm/kvm-s390.c > @@ -172,11 +172,6 @@ static int nested; > module_param(nested, int, S_IRUGO); > MODULE_PARM_DESC(nested, "Nested virtualization support"); > > -/* allow 1m huge page guest backing, if !nested */ > -static int hpage; > -module_param(hpage, int, 0444); > -MODULE_PARM_DESC(hpage, "1m huge page backing support"); > - Do we want to keep the parameter for now? This would allow admins to disable it system-wide as long as it is in its early stage? (just like nested). We can allow co-existence, though. > /* > * For now we handle at most 16 double words as this is what the s390 base > * kernel handles and stores in the prefix page. If we ever need to go beyond > @@ -481,7 +476,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) > break; > case KVM_CAP_S390_HPAGE_1M: > r = 0; > - if (hpage && !kvm_is_ucontrol(kvm)) > + if (!kvm_is_ucontrol(kvm)) > r = 1; > break; > case KVM_CAP_S390_MEM_OP: > @@ -691,7 +686,7 @@ static int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap) > mutex_lock(&kvm->lock); > if (kvm->created_vcpus) > r = -EBUSY; > - else if (!hpage || kvm->arch.use_cmma || kvm_is_ucontrol(kvm)) > + else if (kvm->arch.use_cmma || kvm_is_ucontrol(kvm)) > r = -EINVAL; > else { > r = 0; > @@ -4196,11 +4191,6 @@ static int __init kvm_s390_init(void) > return -ENODEV; > } > > - if (nested && hpage) { > - pr_info("nested (vSIE) and hpage (huge page backing) can currently not be activated concurrently"); > - return -EINVAL; > - } > - > for (i = 0; i < 16; i++) > kvm_s390_fac_base[i] |= > S390_lowcore.stfle_fac_list[i] & nonhyp_mask(i); > diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c > index 8d5ce51637eb..928cb5818a21 100644 > --- a/arch/s390/mm/gmap.c > +++ b/arch/s390/mm/gmap.c > @@ -1830,7 +1830,6 @@ struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce, > unsigned long limit; > int rc; > > - BUG_ON(parent->mm->context.allow_gmap_hpage_1m); > BUG_ON(gmap_is_shadow(parent)); > spin_lock(&parent->shadow_lock); > sg = gmap_find_shadow(parent, asce, edat_level); >
On 9/19/18 10:56 AM, David Hildenbrand wrote: > Am 19.09.18 um 10:48 schrieb Janosch Frank: >> Now that we have VSIE support for VMs with huge memory backing, let's >> make both features usable at the same time. >> >> Signed-off-by: Janosch Frank <frankja@linux.ibm.com> >> --- >> Documentation/virtual/kvm/api.txt | 7 +++---- >> arch/s390/kvm/kvm-s390.c | 14 ++------------ >> arch/s390/mm/gmap.c | 1 - >> 3 files changed, 5 insertions(+), 17 deletions(-) >> >> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt >> index 8d8a372c8340..9ec6d23f41d5 100644 >> --- a/Documentation/virtual/kvm/api.txt >> +++ b/Documentation/virtual/kvm/api.txt >> @@ -4509,15 +4509,14 @@ Do not enable KVM_FEATURE_PV_UNHALT if you disable HLT exits. >> >> Architectures: s390 >> Parameters: none >> -Returns: 0 on success, -EINVAL if hpage module parameter was not set >> - or cmma is enabled, or the VM has the KVM_VM_S390_UCONTROL >> +Returns: 0 on success, -EINVAL if cmma is enabled, or the VM has the KVM_VM_S390_UCONTROL >> flag set >> >> With this capability the KVM support for memory backing with 1m pages >> through hugetlbfs can be enabled for a VM. After the capability is >> enabled, cmma can't be enabled anymore and pfmfi and the storage key >> -interpretation are disabled. If cmma has already been enabled or the >> -hpage module parameter is not set to 1, -EINVAL is returned. >> +interpretation are disabled. If cmma has already been enabled, -EINVAL >> +is returned. >> >> While it is generally possible to create a huge page backed VM without >> this capability, the VM will not be able to run. >> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c >> index ac5da6b0b862..59f53b7c72d6 100644 >> --- a/arch/s390/kvm/kvm-s390.c >> +++ b/arch/s390/kvm/kvm-s390.c >> @@ -172,11 +172,6 @@ static int nested; >> module_param(nested, int, S_IRUGO); >> MODULE_PARM_DESC(nested, "Nested virtualization support"); >> >> -/* allow 1m huge page guest backing, if !nested */ >> -static int hpage; >> -module_param(hpage, int, 0444); >> -MODULE_PARM_DESC(hpage, "1m huge page backing support"); >> - > > > Do we want to keep the parameter for now? > > This would allow admins to disable it system-wide as long as it is in > its early stage? (just like nested). We can allow co-existence, though. Both options are fine with me and considering the fixes needed for the enablement this might be the better option. > >> /* >> * For now we handle at most 16 double words as this is what the s390 base >> * kernel handles and stores in the prefix page. If we ever need to go beyond >> @@ -481,7 +476,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) >> break; >> case KVM_CAP_S390_HPAGE_1M: >> r = 0; >> - if (hpage && !kvm_is_ucontrol(kvm)) >> + if (!kvm_is_ucontrol(kvm)) >> r = 1; >> break; >> case KVM_CAP_S390_MEM_OP: >> @@ -691,7 +686,7 @@ static int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap) >> mutex_lock(&kvm->lock); >> if (kvm->created_vcpus) >> r = -EBUSY; >> - else if (!hpage || kvm->arch.use_cmma || kvm_is_ucontrol(kvm)) >> + else if (kvm->arch.use_cmma || kvm_is_ucontrol(kvm)) >> r = -EINVAL; >> else { >> r = 0; >> @@ -4196,11 +4191,6 @@ static int __init kvm_s390_init(void) >> return -ENODEV; >> } >> >> - if (nested && hpage) { >> - pr_info("nested (vSIE) and hpage (huge page backing) can currently not be activated concurrently"); >> - return -EINVAL; >> - } >> - >> for (i = 0; i < 16; i++) >> kvm_s390_fac_base[i] |= >> S390_lowcore.stfle_fac_list[i] & nonhyp_mask(i); >> diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c >> index 8d5ce51637eb..928cb5818a21 100644 >> --- a/arch/s390/mm/gmap.c >> +++ b/arch/s390/mm/gmap.c >> @@ -1830,7 +1830,6 @@ struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce, >> unsigned long limit; >> int rc; >> >> - BUG_ON(parent->mm->context.allow_gmap_hpage_1m); >> BUG_ON(gmap_is_shadow(parent)); >> spin_lock(&parent->shadow_lock); >> sg = gmap_find_shadow(parent, asce, edat_level); >> >
On 09/19/2018 11:50 AM, Janosch Frank wrote: > On 9/19/18 10:56 AM, David Hildenbrand wrote: >> Am 19.09.18 um 10:48 schrieb Janosch Frank: >>> Now that we have VSIE support for VMs with huge memory backing, let's >>> make both features usable at the same time. >>> >>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com> >>> --- >>> Documentation/virtual/kvm/api.txt | 7 +++---- >>> arch/s390/kvm/kvm-s390.c | 14 ++------------ >>> arch/s390/mm/gmap.c | 1 - >>> 3 files changed, 5 insertions(+), 17 deletions(-) >>> >>> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt >>> index 8d8a372c8340..9ec6d23f41d5 100644 >>> --- a/Documentation/virtual/kvm/api.txt >>> +++ b/Documentation/virtual/kvm/api.txt >>> @@ -4509,15 +4509,14 @@ Do not enable KVM_FEATURE_PV_UNHALT if you disable HLT exits. >>> >>> Architectures: s390 >>> Parameters: none >>> -Returns: 0 on success, -EINVAL if hpage module parameter was not set >>> - or cmma is enabled, or the VM has the KVM_VM_S390_UCONTROL >>> +Returns: 0 on success, -EINVAL if cmma is enabled, or the VM has the KVM_VM_S390_UCONTROL >>> flag set >>> >>> With this capability the KVM support for memory backing with 1m pages >>> through hugetlbfs can be enabled for a VM. After the capability is >>> enabled, cmma can't be enabled anymore and pfmfi and the storage key >>> -interpretation are disabled. If cmma has already been enabled or the >>> -hpage module parameter is not set to 1, -EINVAL is returned. >>> +interpretation are disabled. If cmma has already been enabled, -EINVAL >>> +is returned. >>> >>> While it is generally possible to create a huge page backed VM without >>> this capability, the VM will not be able to run. >>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c >>> index ac5da6b0b862..59f53b7c72d6 100644 >>> --- a/arch/s390/kvm/kvm-s390.c >>> +++ b/arch/s390/kvm/kvm-s390.c >>> @@ -172,11 +172,6 @@ static int nested; >>> module_param(nested, int, S_IRUGO); >>> MODULE_PARM_DESC(nested, "Nested virtualization support"); >>> >>> -/* allow 1m huge page guest backing, if !nested */ >>> -static int hpage; >>> -module_param(hpage, int, 0444); >>> -MODULE_PARM_DESC(hpage, "1m huge page backing support"); >>> - >> >> >> Do we want to keep the parameter for now? >> >> This would allow admins to disable it system-wide as long as it is in >> its early stage? (just like nested). We can allow co-existence, though. > > Both options are fine with me and considering the fixes needed for the > enablement this might be the better option. I think keeping the hpage parameter is fine, but we can consider changing the default to 1.
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 8d8a372c8340..9ec6d23f41d5 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -4509,15 +4509,14 @@ Do not enable KVM_FEATURE_PV_UNHALT if you disable HLT exits. Architectures: s390 Parameters: none -Returns: 0 on success, -EINVAL if hpage module parameter was not set - or cmma is enabled, or the VM has the KVM_VM_S390_UCONTROL +Returns: 0 on success, -EINVAL if cmma is enabled, or the VM has the KVM_VM_S390_UCONTROL flag set With this capability the KVM support for memory backing with 1m pages through hugetlbfs can be enabled for a VM. After the capability is enabled, cmma can't be enabled anymore and pfmfi and the storage key -interpretation are disabled. If cmma has already been enabled or the -hpage module parameter is not set to 1, -EINVAL is returned. +interpretation are disabled. If cmma has already been enabled, -EINVAL +is returned. While it is generally possible to create a huge page backed VM without this capability, the VM will not be able to run. diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index ac5da6b0b862..59f53b7c72d6 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -172,11 +172,6 @@ static int nested; module_param(nested, int, S_IRUGO); MODULE_PARM_DESC(nested, "Nested virtualization support"); -/* allow 1m huge page guest backing, if !nested */ -static int hpage; -module_param(hpage, int, 0444); -MODULE_PARM_DESC(hpage, "1m huge page backing support"); - /* * For now we handle at most 16 double words as this is what the s390 base * kernel handles and stores in the prefix page. If we ever need to go beyond @@ -481,7 +476,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) break; case KVM_CAP_S390_HPAGE_1M: r = 0; - if (hpage && !kvm_is_ucontrol(kvm)) + if (!kvm_is_ucontrol(kvm)) r = 1; break; case KVM_CAP_S390_MEM_OP: @@ -691,7 +686,7 @@ static int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap) mutex_lock(&kvm->lock); if (kvm->created_vcpus) r = -EBUSY; - else if (!hpage || kvm->arch.use_cmma || kvm_is_ucontrol(kvm)) + else if (kvm->arch.use_cmma || kvm_is_ucontrol(kvm)) r = -EINVAL; else { r = 0; @@ -4196,11 +4191,6 @@ static int __init kvm_s390_init(void) return -ENODEV; } - if (nested && hpage) { - pr_info("nested (vSIE) and hpage (huge page backing) can currently not be activated concurrently"); - return -EINVAL; - } - for (i = 0; i < 16; i++) kvm_s390_fac_base[i] |= S390_lowcore.stfle_fac_list[i] & nonhyp_mask(i); diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index 8d5ce51637eb..928cb5818a21 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -1830,7 +1830,6 @@ struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce, unsigned long limit; int rc; - BUG_ON(parent->mm->context.allow_gmap_hpage_1m); BUG_ON(gmap_is_shadow(parent)); spin_lock(&parent->shadow_lock); sg = gmap_find_shadow(parent, asce, edat_level);
Now that we have VSIE support for VMs with huge memory backing, let's make both features usable at the same time. Signed-off-by: Janosch Frank <frankja@linux.ibm.com> --- Documentation/virtual/kvm/api.txt | 7 +++---- arch/s390/kvm/kvm-s390.c | 14 ++------------ arch/s390/mm/gmap.c | 1 - 3 files changed, 5 insertions(+), 17 deletions(-)