From 15c9705f0c8af2d19dede9866aec364746b269ef Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Thu, 19 Mar 2015 17:36:43 +0100 Subject: KVM: s390: interface to query and configure cpu features For now, we only have an interface to query and configure facilities indicated via STFL(E). However, we also have features indicated via SCLP, that have to be indicated to the guest by user space and usually require KVM support. This patch allows user space to query and configure available cpu features for the guest. Please note that disabling a feature doesn't necessarily mean that it is completely disabled (e.g. ESOP is mostly handled by the SIE). We will try our best to disable it. Most features (e.g. SCLP) can't directly be forwarded, as most of them need in addition to hardware support, support in KVM. As we later on want to turn these features in KVM explicitly on/off (to simulate different behavior), we have to filter all features provided by the hardware and make them configurable. Signed-off-by: David Hildenbrand Signed-off-by: Christian Borntraeger --- Documentation/virtual/kvm/devices/vm.txt | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) (limited to 'Documentation/virtual') diff --git a/Documentation/virtual/kvm/devices/vm.txt b/Documentation/virtual/kvm/devices/vm.txt index a9ea8774a45f..0ed6808b9965 100644 --- a/Documentation/virtual/kvm/devices/vm.txt +++ b/Documentation/virtual/kvm/devices/vm.txt @@ -85,6 +85,33 @@ Returns: -EBUSY in case 1 or more vcpus are already activated (only in write -ENOMEM if not enough memory is available to process the ioctl 0 in case of success +2.3. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE_FEAT (r/o) + +Allows user space to retrieve available cpu features. A feature is available if +provided by the hardware and supported by kvm. In theory, cpu features could +even be completely emulated by kvm. + +struct kvm_s390_vm_cpu_feat { + __u64 feat[16]; # Bitmap (1 = feature available), MSB 0 bit numbering +}; + +Parameters: address of a buffer to load the feature list from. +Returns: -EFAULT if the given address is not accessible from kernel space. + 0 in case of success. + +2.4. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR_FEAT (r/w) + +Allows user space to retrieve or change enabled cpu features for all VCPUs of a +VM. Features that are not available cannot be enabled. + +See 2.3. for a description of the parameter struct. + +Parameters: address of a buffer to store/load the feature list from. +Returns: -EFAULT if the given address is not accessible from kernel space. + -EINVAL if a cpu feature that is not available is to be enabled. + -EBUSY if at least one VCPU has already been defined. + 0 in case of success. + 3. GROUP: KVM_S390_VM_TOD Architectures: s390 -- cgit v1.2.3 From 0a763c780b7cb830c250d00ead975778ab948f40 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Wed, 18 May 2016 16:03:47 +0200 Subject: KVM: s390: interface to query and configure cpu subfunctions We have certain instructions that indicate available subfunctions via a query subfunction (crypto functions and ptff), or via a test bit function (plo). By exposing these "subfunction blocks" to user space, we allow user space to 1) query available subfunctions and make sure subfunctions won't get lost during migration - e.g. properly indicate them via a CPU model 2) change the subfunctions to be reported to the guest (even adding unavailable ones) This mechanism works just like the way we indicate the stfl(e) list to user space. This way, user space could even emulate some subfunctions in QEMU in the future. If this is ever applicable, we have to make sure later on, that unsupported subfunctions result in an intercept to QEMU. Please note that support to indicate them to the guest is still missing and requires hardware support. Usually, the IBC takes already care of these subfunctions for migration safety. QEMU should make sure to always set these bits properly according to the machine generation to be emulated. Available subfunctions are only valid in combination with STFLE bits retrieved via KVM_S390_VM_CPU_MACHINE and enabled via KVM_S390_VM_CPU_PROCESSOR. If the applicable bits are available, the indicated subfunctions are guaranteed to be correct. Signed-off-by: David Hildenbrand Signed-off-by: Christian Borntraeger --- Documentation/virtual/kvm/devices/vm.txt | 57 ++++++++++++++++++++ arch/s390/include/uapi/asm/kvm.h | 20 +++++++ arch/s390/kvm/kvm-s390.c | 89 ++++++++++++++++++++++++++++++++ 3 files changed, 166 insertions(+) (limited to 'Documentation/virtual') diff --git a/Documentation/virtual/kvm/devices/vm.txt b/Documentation/virtual/kvm/devices/vm.txt index 0ed6808b9965..8a458f42ded2 100644 --- a/Documentation/virtual/kvm/devices/vm.txt +++ b/Documentation/virtual/kvm/devices/vm.txt @@ -112,6 +112,63 @@ Returns: -EFAULT if the given address is not accessible from kernel space. -EBUSY if at least one VCPU has already been defined. 0 in case of success. +2.5. ATTRIBUTE: KVM_S390_VM_CPU_MACHINE_SUBFUNC (r/o) + +Allows user space to retrieve available cpu subfunctions without any filtering +done by a set IBC. These subfunctions are indicated to the guest VCPU via +query or "test bit" subfunctions and used e.g. by cpacf functions, plo and ptff. + +A subfunction block is only valid if KVM_S390_VM_CPU_MACHINE contains the +STFL(E) bit introducing the affected instruction. If the affected instruction +indicates subfunctions via a "query subfunction", the response block is +contained in the returned struct. If the affected instruction +indicates subfunctions via a "test bit" mechanism, the subfunction codes are +contained in the returned struct in MSB 0 bit numbering. + +struct kvm_s390_vm_cpu_subfunc { + u8 plo[32]; # always valid (ESA/390 feature) + u8 ptff[16]; # valid with TOD-clock steering + u8 kmac[16]; # valid with Message-Security-Assist + u8 kmc[16]; # valid with Message-Security-Assist + u8 km[16]; # valid with Message-Security-Assist + u8 kimd[16]; # valid with Message-Security-Assist + u8 klmd[16]; # valid with Message-Security-Assist + u8 pckmo[16]; # valid with Message-Security-Assist-Extension 3 + u8 kmctr[16]; # valid with Message-Security-Assist-Extension 4 + u8 kmf[16]; # valid with Message-Security-Assist-Extension 4 + u8 kmo[16]; # valid with Message-Security-Assist-Extension 4 + u8 pcc[16]; # valid with Message-Security-Assist-Extension 4 + u8 ppno[16]; # valid with Message-Security-Assist-Extension 5 + u8 reserved[1824]; # reserved for future instructions +}; + +Parameters: address of a buffer to load the subfunction blocks from. +Returns: -EFAULT if the given address is not accessible from kernel space. + 0 in case of success. + +2.6. ATTRIBUTE: KVM_S390_VM_CPU_PROCESSOR_SUBFUNC (r/w) + +Allows user space to retrieve or change cpu subfunctions to be indicated for +all VCPUs of a VM. This attribute will only be available if kernel and +hardware support are in place. + +The kernel uses the configured subfunction blocks for indication to +the guest. A subfunction block will only be used if the associated STFL(E) bit +has not been disabled by user space (so the instruction to be queried is +actually available for the guest). + +As long as no data has been written, a read will fail. The IBC will be used +to determine available subfunctions in this case, this will guarantee backward +compatibility. + +See 2.5. for a description of the parameter struct. + +Parameters: address of a buffer to store/load the subfunction blocks from. +Returns: -EFAULT if the given address is not accessible from kernel space. + -EINVAL when reading, if there was no write yet. + -EBUSY if at least one VCPU has already been defined. + 0 in case of success. + 3. GROUP: KVM_S390_VM_TOD Architectures: s390 diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h index 789c4e27e294..f0818d70d73d 100644 --- a/arch/s390/include/uapi/asm/kvm.h +++ b/arch/s390/include/uapi/asm/kvm.h @@ -102,6 +102,26 @@ struct kvm_s390_vm_cpu_feat { __u64 feat[16]; }; +#define KVM_S390_VM_CPU_PROCESSOR_SUBFUNC 4 +#define KVM_S390_VM_CPU_MACHINE_SUBFUNC 5 +/* for "test bit" instructions MSB 0 bit ordering, for "query" raw blocks */ +struct kvm_s390_vm_cpu_subfunc { + __u8 plo[32]; /* always */ + __u8 ptff[16]; /* with TOD-clock steering */ + __u8 kmac[16]; /* with MSA */ + __u8 kmc[16]; /* with MSA */ + __u8 km[16]; /* with MSA */ + __u8 kimd[16]; /* with MSA */ + __u8 klmd[16]; /* with MSA */ + __u8 pckmo[16]; /* with MSA3 */ + __u8 kmctr[16]; /* with MSA4 */ + __u8 kmf[16]; /* with MSA4 */ + __u8 kmo[16]; /* with MSA4 */ + __u8 pcc[16]; /* with MSA4 */ + __u8 ppno[16]; /* with MSA5 */ + __u8 reserved[1824]; +}; + /* kvm attributes for crypto */ #define KVM_S390_VM_CRYPTO_ENABLE_AES_KW 0 #define KVM_S390_VM_CRYPTO_ENABLE_DEA_KW 1 diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 2b5c14da3227..f746a35e3950 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -36,6 +36,8 @@ #include #include #include +#include +#include #include "kvm-s390.h" #include "gaccess.h" @@ -135,6 +137,8 @@ unsigned long kvm_s390_fac_list_mask_size(void) /* available cpu features supported by kvm */ static DECLARE_BITMAP(kvm_s390_available_cpu_feat, KVM_S390_VM_CPU_FEAT_NR_BITS); +/* available subfunctions indicated via query / "test bit" */ +static struct kvm_s390_vm_cpu_subfunc kvm_s390_available_subfunc; static struct gmap_notifier gmap_notifier; debug_info_t *kvm_s390_dbf; @@ -198,8 +202,52 @@ static void allow_cpu_feat(unsigned long nr) set_bit_inv(nr, kvm_s390_available_cpu_feat); } +static inline int plo_test_bit(unsigned char nr) +{ + register unsigned long r0 asm("0") = (unsigned long) nr | 0x100; + int cc = 3; /* subfunction not available */ + + asm volatile( + /* Parameter registers are ignored for "test bit" */ + " plo 0,0,0,0(0)\n" + " ipm %0\n" + " srl %0,28\n" + : "=d" (cc) + : "d" (r0) + : "cc"); + return cc == 0; +} + static void kvm_s390_cpu_feat_init(void) { + int i; + + for (i = 0; i < 256; ++i) { + if (plo_test_bit(i)) + kvm_s390_available_subfunc.plo[i >> 3] |= 0x80 >> (i & 7); + } + + if (test_facility(28)) /* TOD-clock steering */ + etr_ptff(kvm_s390_available_subfunc.ptff, ETR_PTFF_QAF); + + if (test_facility(17)) { /* MSA */ + __cpacf_query(CPACF_KMAC, kvm_s390_available_subfunc.kmac); + __cpacf_query(CPACF_KMC, kvm_s390_available_subfunc.kmc); + __cpacf_query(CPACF_KM, kvm_s390_available_subfunc.km); + __cpacf_query(CPACF_KIMD, kvm_s390_available_subfunc.kimd); + __cpacf_query(CPACF_KLMD, kvm_s390_available_subfunc.klmd); + } + if (test_facility(76)) /* MSA3 */ + __cpacf_query(CPACF_PCKMO, kvm_s390_available_subfunc.pckmo); + if (test_facility(77)) { /* MSA4 */ + __cpacf_query(CPACF_KMCTR, kvm_s390_available_subfunc.kmctr); + __cpacf_query(CPACF_KMF, kvm_s390_available_subfunc.kmf); + __cpacf_query(CPACF_KMO, kvm_s390_available_subfunc.kmo); + __cpacf_query(CPACF_PCC, kvm_s390_available_subfunc.pcc); + } + if (test_facility(57)) /* MSA5 */ + __cpacf_query(CPACF_PPNO, kvm_s390_available_subfunc.ppno); + if (MACHINE_HAS_ESOP) allow_cpu_feat(KVM_S390_VM_CPU_FEAT_ESOP); } @@ -717,6 +765,16 @@ static int kvm_s390_set_processor_feat(struct kvm *kvm, return ret; } +static int kvm_s390_set_processor_subfunc(struct kvm *kvm, + struct kvm_device_attr *attr) +{ + /* + * Once supported by kernel + hw, we have to store the subfunctions + * in kvm->arch and remember that user space configured them. + */ + return -ENXIO; +} + static int kvm_s390_set_cpu_model(struct kvm *kvm, struct kvm_device_attr *attr) { int ret = -ENXIO; @@ -728,6 +786,9 @@ static int kvm_s390_set_cpu_model(struct kvm *kvm, struct kvm_device_attr *attr) case KVM_S390_VM_CPU_PROCESSOR_FEAT: ret = kvm_s390_set_processor_feat(kvm, attr); break; + case KVM_S390_VM_CPU_PROCESSOR_SUBFUNC: + ret = kvm_s390_set_processor_subfunc(kvm, attr); + break; } return ret; } @@ -801,6 +862,25 @@ static int kvm_s390_get_machine_feat(struct kvm *kvm, return 0; } +static int kvm_s390_get_processor_subfunc(struct kvm *kvm, + struct kvm_device_attr *attr) +{ + /* + * Once we can actually configure subfunctions (kernel + hw support), + * we have to check if they were already set by user space, if so copy + * them from kvm->arch. + */ + return -ENXIO; +} + +static int kvm_s390_get_machine_subfunc(struct kvm *kvm, + struct kvm_device_attr *attr) +{ + if (copy_to_user((void __user *)attr->addr, &kvm_s390_available_subfunc, + sizeof(struct kvm_s390_vm_cpu_subfunc))) + return -EFAULT; + return 0; +} static int kvm_s390_get_cpu_model(struct kvm *kvm, struct kvm_device_attr *attr) { int ret = -ENXIO; @@ -818,6 +898,12 @@ static int kvm_s390_get_cpu_model(struct kvm *kvm, struct kvm_device_attr *attr) case KVM_S390_VM_CPU_MACHINE_FEAT: ret = kvm_s390_get_machine_feat(kvm, attr); break; + case KVM_S390_VM_CPU_PROCESSOR_SUBFUNC: + ret = kvm_s390_get_processor_subfunc(kvm, attr); + break; + case KVM_S390_VM_CPU_MACHINE_SUBFUNC: + ret = kvm_s390_get_machine_subfunc(kvm, attr); + break; } return ret; } @@ -903,8 +989,11 @@ static int kvm_s390_vm_has_attr(struct kvm *kvm, struct kvm_device_attr *attr) case KVM_S390_VM_CPU_MACHINE: case KVM_S390_VM_CPU_PROCESSOR_FEAT: case KVM_S390_VM_CPU_MACHINE_FEAT: + case KVM_S390_VM_CPU_MACHINE_SUBFUNC: ret = 0; break; + /* configuring subfunctions is not supported yet */ + case KVM_S390_VM_CPU_PROCESSOR_SUBFUNC: default: ret = -ENXIO; break; -- cgit v1.2.3 From f9cbd9b02539330ddd349df583fcfc2db8a23b90 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Thu, 3 Mar 2016 09:48:47 +0100 Subject: KVM: s390: provide CMMA attributes only if available Let's not provide the device attribute for cmma enabling and clearing if the hardware doesn't support it. This also helps getting rid of the undocumented return value "-EINVAL" in case CMMA is not available when trying to enable it. Also properly document the meaning of -EINVAL for CMMA clearing. Reviewed-by: Christian Borntraeger Signed-off-by: David Hildenbrand Signed-off-by: Christian Borntraeger --- Documentation/virtual/kvm/api.txt | 2 ++ Documentation/virtual/kvm/devices/vm.txt | 3 ++- arch/s390/kvm/kvm-s390.c | 7 ++++++- 3 files changed, 10 insertions(+), 2 deletions(-) (limited to 'Documentation/virtual') diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index a4482cce4bae..4aac3e51bf9f 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -2520,6 +2520,7 @@ Parameters: struct kvm_device_attr Returns: 0 on success, -1 on error Errors: ENXIO: The group or attribute is unknown/unsupported for this device + or hardware support is missing. EPERM: The attribute cannot (currently) be accessed this way (e.g. read-only attribute, or attribute that only makes sense when the device is in a different state) @@ -2547,6 +2548,7 @@ Parameters: struct kvm_device_attr Returns: 0 on success, -1 on error Errors: ENXIO: The group or attribute is unknown/unsupported for this device + or hardware support is missing. Tests whether a device supports a particular attribute. A successful return indicates the attribute is implemented. It does not necessarily diff --git a/Documentation/virtual/kvm/devices/vm.txt b/Documentation/virtual/kvm/devices/vm.txt index 8a458f42ded2..b6cda49f2ba4 100644 --- a/Documentation/virtual/kvm/devices/vm.txt +++ b/Documentation/virtual/kvm/devices/vm.txt @@ -20,7 +20,8 @@ Enables Collaborative Memory Management Assist (CMMA) for the virtual machine. 1.2. ATTRIBUTE: KVM_S390_VM_MEM_CLR_CMMA Parameters: none -Returns: 0 +Returns: -EINVAL if CMMA was not enabled + 0 otherwise Clear the CMMA status for all guest pages, so any pages the guest marked as unused are again used any may not be reclaimed by the host. diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 005e664f6360..f695c6e08337 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -485,7 +485,7 @@ static int kvm_s390_set_mem_control(struct kvm *kvm, struct kvm_device_attr *att unsigned int idx; switch (attr->attr) { case KVM_S390_VM_MEM_ENABLE_CMMA: - ret = -EINVAL; + ret = -ENXIO; if (!sclp.has_cmma) break; @@ -499,6 +499,9 @@ static int kvm_s390_set_mem_control(struct kvm *kvm, struct kvm_device_attr *att mutex_unlock(&kvm->lock); break; case KVM_S390_VM_MEM_CLR_CMMA: + ret = -ENXIO; + if (!sclp.has_cmma) + break; ret = -EINVAL; if (!kvm->arch.use_cmma) break; @@ -964,6 +967,8 @@ static int kvm_s390_vm_has_attr(struct kvm *kvm, struct kvm_device_attr *attr) switch (attr->attr) { case KVM_S390_VM_MEM_ENABLE_CMMA: case KVM_S390_VM_MEM_CLR_CMMA: + ret = sclp.has_cmma ? 0 : -ENXIO; + break; case KVM_S390_VM_MEM_LIMIT_SIZE: ret = 0; break; -- cgit v1.2.3