Instead of allocating a BSCA and upgrading it for PV or when adding the
65th cpu we can always use the ESCA.
The only downside of the change is that we will always allocate 4 pages
for a 248 cpu ESCA instead of a single page for the BSCA per VM.
In return we can delete a bunch of checks and special handling depending
on the SCA type as well as the whole BSCA to ESCA conversion.
As a fallback we can still run without SCA entries when the SIGP
interpretation facility or ESCA are not available.
Signed-off-by: Christoph Schlameuss <schlameuss@xxxxxxxxxxxxx>
---
arch/s390/include/asm/kvm_host.h | 1 -
arch/s390/kvm/interrupt.c | 71 +++++------------
arch/s390/kvm/kvm-s390.c | 161 ++++++---------------------------------
arch/s390/kvm/kvm-s390.h | 4 +-
4 files changed, 45 insertions(+), 192 deletions(-)
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index f51bac835260f562eaf4bbfd373a24bfdbc43834..d03e354a63d9c931522c1a1607eba8685c24527f 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -631,7 +631,6 @@ struct kvm_s390_pv {
struct kvm_arch{
void *sca;
- int use_esca;
rwlock_t sca_lock;
debug_info_t *dbf;
struct kvm_s390_float_interrupt float_int;
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 60c360c18690f6b94e8483dab2c25f016451204b..95a876ff7aca9c632c3e361275da6781ec070c07 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -51,21 +51,11 @@ static int sca_ext_call_pending(struct kvm_vcpu *vcpu, int *src_id)
BUG_ON(!kvm_s390_use_sca_entries());
read_lock(&vcpu->kvm->arch.sca_lock);
- if (vcpu->kvm->arch.use_esca) {
- struct esca_block *sca = vcpu->kvm->arch.sca;
- union esca_sigp_ctrl sigp_ctrl =
- sca->cpu[vcpu->vcpu_id].sigp_ctrl;
+ struct esca_block *sca = vcpu->kvm->arch.sca;
+ union esca_sigp_ctrl sigp_ctrl = sca->cpu[vcpu->vcpu_id].sigp_ctrl;
- c = sigp_ctrl.c;
- scn = sigp_ctrl.scn;
- } else {
- struct bsca_block *sca = vcpu->kvm->arch.sca;
- union bsca_sigp_ctrl sigp_ctrl =
- sca->cpu[vcpu->vcpu_id].sigp_ctrl;
-
- c = sigp_ctrl.c;
- scn = sigp_ctrl.scn;
- }
+ c = sigp_ctrl.c;
+ scn = sigp_ctrl.scn;
read_unlock(&vcpu->kvm->arch.sca_lock);
if (src_id)
@@ -80,33 +70,17 @@ static int sca_inject_ext_call(struct kvm_vcpu *vcpu, int src_id)
BUG_ON(!kvm_s390_use_sca_entries());
read_lock(&vcpu->kvm->arch.sca_lock);
- if (vcpu->kvm->arch.use_esca) {
- struct esca_block *sca = vcpu->kvm->arch.sca;
- union esca_sigp_ctrl *sigp_ctrl =
- &(sca->cpu[vcpu->vcpu_id].sigp_ctrl);
- union esca_sigp_ctrl new_val = {0}, old_val;
-
- old_val = READ_ONCE(*sigp_ctrl);
- new_val.scn = src_id;
- new_val.c = 1;
- old_val.c = 0;
-
- expect = old_val.value;
- rc = cmpxchg(&sigp_ctrl->value, old_val.value, new_val.value);
- } else {
- struct bsca_block *sca = vcpu->kvm->arch.sca;
- union bsca_sigp_ctrl *sigp_ctrl =
- &(sca->cpu[vcpu->vcpu_id].sigp_ctrl);
- union bsca_sigp_ctrl new_val = {0}, old_val;
+ struct esca_block *sca = vcpu->kvm->arch.sca;
+ union esca_sigp_ctrl *sigp_ctrl = &sca->cpu[vcpu->vcpu_id].sigp_ctrl;
+ union esca_sigp_ctrl new_val = {0}, old_val;
- old_val = READ_ONCE(*sigp_ctrl);
- new_val.scn = src_id;
- new_val.c = 1;
- old_val.c = 0;
+ old_val = READ_ONCE(*sigp_ctrl);
+ new_val.scn = src_id;
+ new_val.c = 1;
+ old_val.c = 0;
- expect = old_val.value;
- rc = cmpxchg(&sigp_ctrl->value, old_val.value, new_val.value);
- }
+ expect = old_val.value;
+ rc = cmpxchg(&sigp_ctrl->value, old_val.value, new_val.value);
read_unlock(&vcpu->kvm->arch.sca_lock);
if (rc != expect) {
@@ -123,19 +97,10 @@ static void sca_clear_ext_call(struct kvm_vcpu *vcpu)
return;
kvm_s390_clear_cpuflags(vcpu, CPUSTAT_ECALL_PEND);
read_lock(&vcpu->kvm->arch.sca_lock);
- if (vcpu->kvm->arch.use_esca) {
- struct esca_block *sca = vcpu->kvm->arch.sca;
- union esca_sigp_ctrl *sigp_ctrl =
- &(sca->cpu[vcpu->vcpu_id].sigp_ctrl);
+ struct esca_block *sca = vcpu->kvm->arch.sca;
+ union esca_sigp_ctrl *sigp_ctrl = &sca->cpu[vcpu->vcpu_id].sigp_ctrl;
- WRITE_ONCE(sigp_ctrl->value, 0);
- } else {
- struct bsca_block *sca = vcpu->kvm->arch.sca;
- union bsca_sigp_ctrl *sigp_ctrl =
- &(sca->cpu[vcpu->vcpu_id].sigp_ctrl);
-
- WRITE_ONCE(sigp_ctrl->value, 0);
- }
+ WRITE_ONCE(sigp_ctrl->value, 0);
read_unlock(&vcpu->kvm->arch.sca_lock);
}
@@ -1223,7 +1188,7 @@ int kvm_s390_ext_call_pending(struct kvm_vcpu *vcpu)
{
struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int;
- if (!sclp.has_sigpif)
+ if (!kvm_s390_use_sca_entries())
return test_bit(IRQ_PEND_EXT_EXTERNAL, &li->pending_irqs);
return sca_ext_call_pending(vcpu, NULL);
@@ -1547,7 +1512,7 @@ static int __inject_extcall(struct kvm_vcpu *vcpu, struct kvm_s390_irq *irq)
if (kvm_get_vcpu_by_id(vcpu->kvm, src_id) == NULL)
return -EINVAL;
- if (sclp.has_sigpif && !kvm_s390_pv_cpu_get_handle(vcpu))
+ if (kvm_s390_use_sca_entries() && !kvm_s390_pv_cpu_get_handle(vcpu))
return sca_inject_ext_call(vcpu, src_id);
if (test_and_set_bit(IRQ_PEND_EXT_EXTERNAL, &li->pending_irqs))
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index b65e4cbe67cf70a7d614607ebdd679060e7d31f4..473e399056fb31d341d9a00a9295e37a8aa66ab7 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -271,7 +271,6 @@ debug_info_t *kvm_s390_dbf_uv;
/* forward declarations */
static void kvm_gmap_notifier(struct gmap *gmap, unsigned long start,
unsigned long end);
-static int sca_switch_to_extended(struct kvm *kvm);
static void kvm_clock_sync_scb(struct kvm_s390_sie_block *scb, u64 delta)
{
@@ -631,11 +630,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
case KVM_CAP_NR_VCPUS:
case KVM_CAP_MAX_VCPUS:
case KVM_CAP_MAX_VCPU_ID:
- r = KVM_S390_BSCA_CPU_SLOTS;
+ r = KVM_S390_ESCA_CPU_SLOTS;
if (!kvm_s390_use_sca_entries())
r = KVM_MAX_VCPUS;
- else if (sclp.has_esca && sclp.has_64bscao)
- r = KVM_S390_ESCA_CPU_SLOTS;
if (ext == KVM_CAP_NR_VCPUS)
r = min_t(unsigned int, num_online_cpus(), r);
else if (ext == KVM_CAP_MAX_VCPU_ID)
@@ -1932,13 +1929,11 @@ static int kvm_s390_get_cpu_model(struct kvm *kvm, struct kvm_device_attr *attr)
* Updates the Multiprocessor Topology-Change-Report bit to signal
* the guest with a topology change.
* This is only relevant if the topology facility is present.
- *
- * The SCA version, bsca or esca, doesn't matter as offset is the same.
*/
static void kvm_s390_update_topology_change_report(struct kvm *kvm, bool val)
{
union sca_utility new, old;
- struct bsca_block *sca;
+ struct esca_block *sca;
read_lock(&kvm->arch.sca_lock);
sca = kvm->arch.sca;
@@ -1969,7 +1964,7 @@ static int kvm_s390_get_topo_change_indication(struct kvm *kvm,
return -ENXIO;
read_lock(&kvm->arch.sca_lock);
- topo = ((struct bsca_block *)kvm->arch.sca)->utility.mtcr;
+ topo = ((struct esca_block *)kvm->arch.sca)->utility.mtcr;
read_unlock(&kvm->arch.sca_lock);
return put_user(topo, (u8 __user *)attr->addr);
@@ -2668,14 +2663,6 @@ static int kvm_s390_handle_pv(struct kvm *kvm, struct kvm_pv_cmd *cmd)
if (kvm_s390_pv_is_protected(kvm))
break;
- /*
- * FMT 4 SIE needs esca. As we never switch back to bsca from
- * esca, we need no cleanup in the error cases below
- */
- r = sca_switch_to_extended(kvm);
- if (r)
- break;
-
r = s390_disable_cow_sharing();
if (r)
break;
@@ -3316,10 +3303,7 @@ static void kvm_s390_crypto_init(struct kvm *kvm)
static void sca_dispose(struct kvm *kvm)
{
- if (kvm->arch.use_esca)
- free_pages_exact(kvm->arch.sca, sizeof(struct esca_block));
- else
- free_page((unsigned long)(kvm->arch.sca));
+ free_pages_exact(kvm->arch.sca, sizeof(struct esca_block));
kvm->arch.sca = NULL;
}
@@ -3333,10 +3317,9 @@ void kvm_arch_free_vm(struct kvm *kvm)
int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
{
- gfp_t alloc_flags = GFP_KERNEL_ACCOUNT;
- int i, rc;
+ gfp_t alloc_flags = GFP_KERNEL_ACCOUNT | __GFP_ZERO;
char debug_name[16];
- static unsigned long sca_offset;
+ int i, rc;
rc = -EINVAL;
#ifdef CONFIG_KVM_S390_UCONTROL
@@ -3358,17 +3341,12 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
if (!sclp.has_64bscao)
alloc_flags |= GFP_DMA;
rwlock_init(&kvm->arch.sca_lock);
- /* start with basic SCA */
- kvm->arch.sca = (struct bsca_block *) get_zeroed_page(alloc_flags);
- if (!kvm->arch.sca)
- goto out_err;
mutex_lock(&kvm_lock);
- sca_offset += 16;
- if (sca_offset + sizeof(struct bsca_block) > PAGE_SIZE)
- sca_offset = 0;
- kvm->arch.sca = (struct bsca_block *)
- ((char *) kvm->arch.sca + sca_offset);
+
+ kvm->arch.sca = alloc_pages_exact(sizeof(*kvm->arch.sca), alloc_flags);
mutex_unlock(&kvm_lock);
+ if (!kvm->arch.sca)
+ goto out_err;
sprintf(debug_name, "kvm-%u", current->pid);
@@ -3550,17 +3528,10 @@ static void sca_del_vcpu(struct kvm_vcpu *vcpu)
if (!kvm_s390_use_sca_entries())
return;
read_lock(&vcpu->kvm->arch.sca_lock);
- if (vcpu->kvm->arch.use_esca) {
- struct esca_block *sca = vcpu->kvm->arch.sca;
-
- clear_bit_inv(vcpu->vcpu_id, (unsigned long *) sca->mcn);
- sca->cpu[vcpu->vcpu_id].sda = 0;
- } else {
- struct bsca_block *sca = vcpu->kvm->arch.sca;
+ struct esca_block *sca = vcpu->kvm->arch.sca;
- clear_bit_inv(vcpu->vcpu_id, (unsigned long *) &sca->mcn);
- sca->cpu[vcpu->vcpu_id].sda = 0;
- }
+ clear_bit_inv(vcpu->vcpu_id, (unsigned long *)sca->mcn);
+ sca->cpu[vcpu->vcpu_id].sda = 0;
read_unlock(&vcpu->kvm->arch.sca_lock);
}
@@ -3575,105 +3546,23 @@ static void sca_add_vcpu(struct kvm_vcpu *vcpu)
return;
}
read_lock(&vcpu->kvm->arch.sca_lock);
- if (vcpu->kvm->arch.use_esca) {
- struct esca_block *sca = vcpu->kvm->arch.sca;
- phys_addr_t sca_phys = virt_to_phys(sca);
-
- sca->cpu[vcpu->vcpu_id].sda = virt_to_phys(vcpu->arch.sie_block);
- vcpu->arch.sie_block->scaoh = sca_phys >> 32;
- vcpu->arch.sie_block->scaol = sca_phys & ESCA_SCAOL_MASK;
- vcpu->arch.sie_block->ecb2 |= ECB2_ESCA;
- set_bit_inv(vcpu->vcpu_id, (unsigned long *) sca->mcn);
- } else {
- struct bsca_block *sca = vcpu->kvm->arch.sca;
- phys_addr_t sca_phys = virt_to_phys(sca);
-
- sca->cpu[vcpu->vcpu_id].sda = virt_to_phys(vcpu->arch.sie_block);
- vcpu->arch.sie_block->scaoh = sca_phys >> 32;
- vcpu->arch.sie_block->scaol = sca_phys;
- set_bit_inv(vcpu->vcpu_id, (unsigned long *) &sca->mcn);
- }
+ struct esca_block *sca = vcpu->kvm->arch.sca;
+ phys_addr_t sca_phys = virt_to_phys(sca);
+
+ sca->cpu[vcpu->vcpu_id].sda = virt_to_phys(vcpu->arch.sie_block);
+ vcpu->arch.sie_block->scaoh = sca_phys >> 32;
+ vcpu->arch.sie_block->scaol = sca_phys & ESCA_SCAOL_MASK;
+ vcpu->arch.sie_block->ecb2 |= ECB2_ESCA;
+ set_bit_inv(vcpu->vcpu_id, (unsigned long *)sca->mcn);
read_unlock(&vcpu->kvm->arch.sca_lock);
}
-/* Basic SCA to Extended SCA data copy routines */
-static inline void sca_copy_entry(struct esca_entry *d, struct bsca_entry *s)
-{
- d->sda = s->sda;
- d->sigp_ctrl.c = s->sigp_ctrl.c;
- d->sigp_ctrl.scn = s->sigp_ctrl.scn;
-}
-
-static void sca_copy_b_to_e(struct esca_block *d, struct bsca_block *s)
-{
- int i;
-
- d->ipte_control = s->ipte_control;
- d->mcn[0] = s->mcn;
- for (i = 0; i < KVM_S390_BSCA_CPU_SLOTS; i++)
- sca_copy_entry(&d->cpu[i], &s->cpu[i]);
-}
-
-static int sca_switch_to_extended(struct kvm *kvm)
-{
- struct bsca_block *old_sca = kvm->arch.sca;
- struct esca_block *new_sca;
- struct kvm_vcpu *vcpu;
- unsigned long vcpu_idx;
- u32 scaol, scaoh;
- phys_addr_t new_sca_phys;
-
- if (kvm->arch.use_esca)
- return 0;
-
- new_sca = alloc_pages_exact(sizeof(*new_sca), GFP_KERNEL_ACCOUNT | __GFP_ZERO);
- if (!new_sca)
- return -ENOMEM;
-
- new_sca_phys = virt_to_phys(new_sca);
- scaoh = new_sca_phys >> 32;
- scaol = new_sca_phys & ESCA_SCAOL_MASK;
-
- kvm_s390_vcpu_block_all(kvm);
- write_lock(&kvm->arch.sca_lock);
-
- sca_copy_b_to_e(new_sca, old_sca);
-
- kvm_for_each_vcpu(vcpu_idx, vcpu, kvm) {
- vcpu->arch.sie_block->scaoh = scaoh;
- vcpu->arch.sie_block->scaol = scaol;
- vcpu->arch.sie_block->ecb2 |= ECB2_ESCA;
- }
- kvm->arch.sca = new_sca;
- kvm->arch.use_esca = 1;
-
- write_unlock(&kvm->arch.sca_lock);
- kvm_s390_vcpu_unblock_all(kvm);
-
- free_page((unsigned long)old_sca);
-
- VM_EVENT(kvm, 2, "Switched to ESCA (0x%p -> 0x%p)",
- old_sca, kvm->arch.sca);
- return 0;
-}
-
static int sca_can_add_vcpu(struct kvm *kvm, unsigned int id)
{
- int rc;
-
- if (!kvm_s390_use_sca_entries()) {
- if (id < KVM_MAX_VCPUS)
- return true;
- return false;
- }
- if (id < KVM_S390_BSCA_CPU_SLOTS)
- return true;
- if (!sclp.has_esca || !sclp.has_64bscao)
- return false;
-
- rc = kvm->arch.use_esca ? 0 : sca_switch_to_extended(kvm);
+ if (!kvm_s390_use_sca_entries())
+ return id < KVM_MAX_VCPUS;
- return rc == 0 && id < KVM_S390_ESCA_CPU_SLOTS;
+ return id < KVM_S390_ESCA_CPU_SLOTS;
}
/* needs disabled preemption to protect from TOD sync and vcpu_load/put */
@@ -3919,7 +3808,7 @@ static int kvm_s390_vcpu_setup(struct kvm_vcpu *vcpu)
vcpu->arch.sie_block->eca |= ECA_IB;
if (sclp.has_siif)
vcpu->arch.sie_block->eca |= ECA_SII;
- if (sclp.has_sigpif)
+ if (kvm_s390_use_sca_entries())
vcpu->arch.sie_block->eca |= ECA_SIGPI;
if (test_kvm_facility(vcpu->kvm, 129)) {
vcpu->arch.sie_block->eca |= ECA_VX;
diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 8d3bbb2dd8d27802bbde2a7bd1378033ad614b8e..2c8e177e4af8f2dab07fd42a904cefdea80f6855 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -531,7 +531,7 @@ int kvm_s390_handle_per_event(struct kvm_vcpu *vcpu);
/* support for Basic/Extended SCA handling */
static inline union ipte_control *kvm_s390_get_ipte_control(struct kvm *kvm)
{
- struct bsca_block *sca = kvm->arch.sca; /* SCA version doesn't matter */
+ struct esca_block *sca = kvm->arch.sca; /* SCA version doesn't matter */
return &sca->ipte_control;
}
@@ -542,7 +542,7 @@ static inline int kvm_s390_use_sca_entries(void)
* might use the entries. By not setting the entries and keeping them
* invalid, hardware will not access them but intercept.
*/
- return sclp.has_sigpif;
+ return sclp.has_sigpif && sclp.has_esca;
}
void kvm_s390_reinject_machine_check(struct kvm_vcpu *vcpu,
struct mcck_volatile_info *mcck_info);
--
2.49.0
