| Message ID | 1521051954-25715-4-git-send-email-akrowiak@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, 14 Mar 2018 14:25:43 -0400 Tony Krowiak <akrowiak@linux.vnet.ibm.com> wrote: > Introduces a new CPU model feature and two CPU model > facilities to support AP virtualization for KVM guests. > > CPU model feature: > > The KVM_S390_VM_CPU_FEAT_AP feature indicates that > AP instructions are available on the guest. This > feature will be enabled by the kernel only if the AP > instructions are installed on the linux host. This feature > must be specifically turned on for the KVM guest from > userspace to use the VFIO AP device driver for guest > access to AP devices. > > CPU model facilities: > > 1. AP Query Configuration Information (QCI) facility is installed. > > This is indicated by setting facilities bit 12 for > the guest. The kernel will not enable this facility > for the guest if it is not set on the host. This facility > must not be set by userspace if the KVM_S390_VM_CPU_FEAT_AP > feature is not installed. > > 2. AP Facilities Test facility (APFT) is installed. > > This is indicated by setting facilities bit 15 for > the guest. The kernel will not enable this facility for > the guest if it is not set on the host. This facility > must not be set by userspace if the KVM_S390_VM_CPU_FEAT_AP > feature is not installed. > > Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> > Reviewed-by: Halil Pasic <pasic@linux.vnet.ibm.com> > Signed-off-by: Tony Krowiak <akrowiak@linux.vnet.ibm.com> > --- > arch/s390/include/asm/kvm_host.h | 1 + > arch/s390/include/uapi/asm/kvm.h | 1 + > arch/s390/kvm/kvm-s390.c | 4 ++++ > arch/s390/tools/gen_facilities.c | 2 ++ > 4 files changed, 8 insertions(+), 0 deletions(-) > > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > index c47731d..a60c45b 100644 > --- a/arch/s390/kvm/kvm-s390.c > +++ b/arch/s390/kvm/kvm-s390.c > @@ -350,6 +350,10 @@ static void kvm_s390_cpu_feat_init(void) > > if (MACHINE_HAS_ESOP) > allow_cpu_feat(KVM_S390_VM_CPU_FEAT_ESOP); > + > + if (ap_instructions_installed()) /* AP instructions installed on host */ > + allow_cpu_feat(KVM_S390_VM_CPU_FEAT_AP); That's another dependency of the base kvm-s390 module on zcrypt, which I don't like at all. There are two possibilities here: - Exposing the features makes sense even if no zcrypt driver is active in the host. Then, ap_instructions_installed() needs to be moved into always-built code (see my comments for the interface in patch 1). - Exposing the features makes sense only if we actually want to make vfio-ap available. Then we should provide the proper check in the vfio-ap parts (which depends on zcrypt) and stub it out if vfio-ap is not configured. > + > /* > * We need SIE support, ESOP (PROT_READ protection for gmap_shadow), > * 64bit SCAO (SCA passthrough) and IDTE (for gmap_shadow unshadowing).
On 27/03/2018 12:59, Cornelia Huck wrote: > On Wed, 14 Mar 2018 14:25:43 -0400 > Tony Krowiak <akrowiak@linux.vnet.ibm.com> wrote: > >> Introduces a new CPU model feature and two CPU model >> facilities to support AP virtualization for KVM guests. >> >> CPU model feature: >> >> The KVM_S390_VM_CPU_FEAT_AP feature indicates that >> AP instructions are available on the guest. This >> feature will be enabled by the kernel only if the AP >> instructions are installed on the linux host. This feature >> must be specifically turned on for the KVM guest from >> userspace to use the VFIO AP device driver for guest >> access to AP devices. >> >> CPU model facilities: >> >> 1. AP Query Configuration Information (QCI) facility is installed. >> >> This is indicated by setting facilities bit 12 for >> the guest. The kernel will not enable this facility >> for the guest if it is not set on the host. This facility >> must not be set by userspace if the KVM_S390_VM_CPU_FEAT_AP >> feature is not installed. >> >> 2. AP Facilities Test facility (APFT) is installed. >> >> This is indicated by setting facilities bit 15 for >> the guest. The kernel will not enable this facility for >> the guest if it is not set on the host. This facility >> must not be set by userspace if the KVM_S390_VM_CPU_FEAT_AP >> feature is not installed. >> >> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> >> Reviewed-by: Halil Pasic <pasic@linux.vnet.ibm.com> >> Signed-off-by: Tony Krowiak <akrowiak@linux.vnet.ibm.com> >> --- >> arch/s390/include/asm/kvm_host.h | 1 + >> arch/s390/include/uapi/asm/kvm.h | 1 + >> arch/s390/kvm/kvm-s390.c | 4 ++++ >> arch/s390/tools/gen_facilities.c | 2 ++ >> 4 files changed, 8 insertions(+), 0 deletions(-) >> >> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c >> index c47731d..a60c45b 100644 >> --- a/arch/s390/kvm/kvm-s390.c >> +++ b/arch/s390/kvm/kvm-s390.c >> @@ -350,6 +350,10 @@ static void kvm_s390_cpu_feat_init(void) >> >> if (MACHINE_HAS_ESOP) >> allow_cpu_feat(KVM_S390_VM_CPU_FEAT_ESOP); >> + >> + if (ap_instructions_installed()) /* AP instructions installed on host */ >> + allow_cpu_feat(KVM_S390_VM_CPU_FEAT_AP); > That's another dependency of the base kvm-s390 module on zcrypt, which > I don't like at all. In fact there is a tricky thing about zcrypt it is that even it is configured a a module CONFIG_ZCRYPT=M, the AP BUS is built statically with the kernel. See drivers/s390/crypto/Makefile " ap-objs := ap_bus.o ap_card.o ap_queue.o obj-$(subst m,y,$(CONFIG_ZCRYPT)) += ap.o " ugly isn't it? > > There are two possibilities here: > - Exposing the features makes sense even if no zcrypt driver is active > in the host. Then, ap_instructions_installed() needs to be moved into > always-built code (see my comments for the interface in patch 1). This is what we need for future enhancement I think. > - Exposing the features makes sense only if we actually want to make > vfio-ap available. Then we should provide the proper check in the > vfio-ap parts (which depends on zcrypt) and stub it out if vfio-ap is > not configured. > >> + >> /* >> * We need SIE support, ESOP (PROT_READ protection for gmap_shadow), >> * 64bit SCAO (SCA passthrough) and IDTE (for gmap_shadow unshadowing).
On Tue, 27 Mar 2018 13:22:56 +0200 Pierre Morel <pmorel@linux.vnet.ibm.com> wrote: > On 27/03/2018 12:59, Cornelia Huck wrote: > > On Wed, 14 Mar 2018 14:25:43 -0400 > > Tony Krowiak <akrowiak@linux.vnet.ibm.com> wrote: > > > >> Introduces a new CPU model feature and two CPU model > >> facilities to support AP virtualization for KVM guests. > >> > >> CPU model feature: > >> > >> The KVM_S390_VM_CPU_FEAT_AP feature indicates that > >> AP instructions are available on the guest. This > >> feature will be enabled by the kernel only if the AP > >> instructions are installed on the linux host. This feature > >> must be specifically turned on for the KVM guest from > >> userspace to use the VFIO AP device driver for guest > >> access to AP devices. > >> > >> CPU model facilities: > >> > >> 1. AP Query Configuration Information (QCI) facility is installed. > >> > >> This is indicated by setting facilities bit 12 for > >> the guest. The kernel will not enable this facility > >> for the guest if it is not set on the host. This facility > >> must not be set by userspace if the KVM_S390_VM_CPU_FEAT_AP > >> feature is not installed. > >> > >> 2. AP Facilities Test facility (APFT) is installed. > >> > >> This is indicated by setting facilities bit 15 for > >> the guest. The kernel will not enable this facility for > >> the guest if it is not set on the host. This facility > >> must not be set by userspace if the KVM_S390_VM_CPU_FEAT_AP > >> feature is not installed. > >> > >> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> > >> Reviewed-by: Halil Pasic <pasic@linux.vnet.ibm.com> > >> Signed-off-by: Tony Krowiak <akrowiak@linux.vnet.ibm.com> > >> --- > >> arch/s390/include/asm/kvm_host.h | 1 + > >> arch/s390/include/uapi/asm/kvm.h | 1 + > >> arch/s390/kvm/kvm-s390.c | 4 ++++ > >> arch/s390/tools/gen_facilities.c | 2 ++ > >> 4 files changed, 8 insertions(+), 0 deletions(-) > >> > >> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > >> index c47731d..a60c45b 100644 > >> --- a/arch/s390/kvm/kvm-s390.c > >> +++ b/arch/s390/kvm/kvm-s390.c > >> @@ -350,6 +350,10 @@ static void kvm_s390_cpu_feat_init(void) > >> > >> if (MACHINE_HAS_ESOP) > >> allow_cpu_feat(KVM_S390_VM_CPU_FEAT_ESOP); > >> + > >> + if (ap_instructions_installed()) /* AP instructions installed on host */ > >> + allow_cpu_feat(KVM_S390_VM_CPU_FEAT_AP); > > That's another dependency of the base kvm-s390 module on zcrypt, which > > I don't like at all. > > In fact there is a tricky thing about zcrypt it is that even it is > configured a a module > CONFIG_ZCRYPT=M, the AP BUS is built statically with the kernel. > See drivers/s390/crypto/Makefile > " > ap-objs := ap_bus.o ap_card.o ap_queue.o > obj-$(subst m,y,$(CONFIG_ZCRYPT)) += ap.o > " > ugly isn't it? Yeah, I found it... interesting the first time I saw it. > > > > > There are two possibilities here: > > - Exposing the features makes sense even if no zcrypt driver is active > > in the host. Then, ap_instructions_installed() needs to be moved into > > always-built code (see my comments for the interface in patch 1). > > This is what we need for future enhancement I think. OK, so that function needs to go into whatever place the interface used in patch 1 goes to as well. > > > - Exposing the features makes sense only if we actually want to make > > vfio-ap available. Then we should provide the proper check in the > > vfio-ap parts (which depends on zcrypt) and stub it out if vfio-ap is > > not configured. > > > >> + > >> /* > >> * We need SIE support, ESOP (PROT_READ protection for gmap_shadow), > >> * 64bit SCAO (SCA passthrough) and IDTE (for gmap_shadow unshadowing). > >
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index 65a944e..98957c2 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -186,6 +186,7 @@ struct kvm_s390_sie_block { #define ECA_AIV 0x00200000 #define ECA_VX 0x00020000 #define ECA_PROTEXCI 0x00002000 +#define ECA_APIE 0x00000008 #define ECA_SII 0x00000001 __u32 eca; /* 0x004c */ #define ICPT_INST 0x04 diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h index 4cdaa55..a580dec 100644 --- a/arch/s390/include/uapi/asm/kvm.h +++ b/arch/s390/include/uapi/asm/kvm.h @@ -130,6 +130,7 @@ struct kvm_s390_vm_cpu_machine { #define KVM_S390_VM_CPU_FEAT_PFMFI 11 #define KVM_S390_VM_CPU_FEAT_SIGPIF 12 #define KVM_S390_VM_CPU_FEAT_KSS 13 +#define KVM_S390_VM_CPU_FEAT_AP 14 struct kvm_s390_vm_cpu_feat { __u64 feat[16]; }; diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index c47731d..a60c45b 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -350,6 +350,10 @@ static void kvm_s390_cpu_feat_init(void) if (MACHINE_HAS_ESOP) allow_cpu_feat(KVM_S390_VM_CPU_FEAT_ESOP); + + if (ap_instructions_installed()) /* AP instructions installed on host */ + allow_cpu_feat(KVM_S390_VM_CPU_FEAT_AP); + /* * We need SIE support, ESOP (PROT_READ protection for gmap_shadow), * 64bit SCAO (SCA passthrough) and IDTE (for gmap_shadow unshadowing). diff --git a/arch/s390/tools/gen_facilities.c b/arch/s390/tools/gen_facilities.c index 83ffefc..a8ae59a 100644 --- a/arch/s390/tools/gen_facilities.c +++ b/arch/s390/tools/gen_facilities.c @@ -107,6 +107,8 @@ struct facility_def { .name = "FACILITIES_KVM_CPUMODEL", .bits = (int[]){ + 12, /* AP Query Configuration Information */ + 15, /* AP Facilities Test */ -1 /* END */ } },