[J][PATCH 1/1] KVM: s390: pv: make use of ultravisor AIV support
frank.heimes at canonical.com
frank.heimes at canonical.com
Wed Mar 9 15:51:44 UTC 2022
From: Michael Mueller <mimu at linux.ibm.com>
BugLink: https://bugs.launchpad.net/bugs/1959977
This patch enables the ultravisor adapter interruption vitualization
support indicated by UV feature BIT_UV_FEAT_AIV. This allows ISC
interruption injection directly into the GISA IPM for PV kvm guests.
Hardware that does not support this feature will continue to use the
UV interruption interception method to deliver ISC interruptions to
PV kvm guests. For this purpose, the ECA_AIV bit for all guest cpus
will be cleared and the GISA will be disabled during PV CPU setup.
In addition a check in __inject_io() has been removed. That reduces the
required instructions for interruption handling for PV and traditional
kvm guests.
Signed-off-by: Michael Mueller <mimu at linux.ibm.com>
Reviewed-by: Janosch Frank <frankja at linux.ibm.com>
Link: https://lore.kernel.org/r/20220209152217.1793281-2-mimu@linux.ibm.com
Reviewed-by: Christian Borntraeger <borntraeger at linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger at linux.ibm.com>
(backported from commit ee6a569d3bf64c9676eee3eecb861fb01cc11311 linux-next)
[Frank Heimes: Resolve minor conflict due to context change.]
Signed-off-by: Frank Heimes <frank.heimes at canonical.com>
---
arch/s390/include/asm/uv.h | 1 +
arch/s390/kvm/interrupt.c | 54 +++++++++++++++++++++++++++++++++-----
arch/s390/kvm/kvm-s390.c | 11 +++++---
arch/s390/kvm/kvm-s390.h | 11 ++++++++
4 files changed, 68 insertions(+), 9 deletions(-)
diff --git a/arch/s390/include/asm/uv.h b/arch/s390/include/asm/uv.h
index fe92a4caf5ec..affc7b502461 100644
--- a/arch/s390/include/asm/uv.h
+++ b/arch/s390/include/asm/uv.h
@@ -75,6 +75,7 @@ enum uv_cmds_inst {
enum uv_feat_ind {
BIT_UV_FEAT_MISC = 0,
+ BIT_UV_FEAT_AIV = 1,
};
struct uv_cb_header {
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 8ce03a5ca863..1380ba68abbe 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -1900,13 +1900,12 @@ static int __inject_io(struct kvm *kvm, struct kvm_s390_interrupt_info *inti)
isc = int_word_to_isc(inti->io.io_int_word);
/*
- * Do not make use of gisa in protected mode. We do not use the lock
- * checking variant as this is just a performance optimization and we
- * do not hold the lock here. This is ok as the code will pick
- * interrupts from both "lists" for delivery.
+ * We do not use the lock checking variant as this is just a
+ * performance optimization and we do not hold the lock here.
+ * This is ok as the code will pick interrupts from both "lists"
+ * for delivery.
*/
- if (!kvm_s390_pv_get_handle(kvm) &&
- gi->origin && inti->type & KVM_S390_INT_IO_AI_MASK) {
+ if (gi->origin && inti->type & KVM_S390_INT_IO_AI_MASK) {
VM_EVENT(kvm, 4, "%s isc %1u", "inject: I/O (AI/gisa)", isc);
gisa_set_ipm_gisc(gi->origin, isc);
kfree(inti);
@@ -3170,9 +3169,33 @@ void kvm_s390_gisa_init(struct kvm *kvm)
VM_EVENT(kvm, 3, "gisa 0x%pK initialized", gi->origin);
}
+void kvm_s390_gisa_enable(struct kvm *kvm)
+{
+ struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int;
+ struct kvm_vcpu *vcpu;
+ unsigned long i;
+ u32 gisa_desc;
+
+ if (gi->origin)
+ return;
+ kvm_s390_gisa_init(kvm);
+ gisa_desc = kvm_s390_get_gisa_desc(kvm);
+ if (!gisa_desc)
+ return;
+ kvm_for_each_vcpu(i, vcpu, kvm) {
+ mutex_lock(&vcpu->mutex);
+ vcpu->arch.sie_block->gd = gisa_desc;
+ vcpu->arch.sie_block->eca |= ECA_AIV;
+ VCPU_EVENT(vcpu, 3, "AIV gisa format-%u enabled for cpu %03u",
+ vcpu->arch.sie_block->gd & 0x3, vcpu->vcpu_id);
+ mutex_unlock(&vcpu->mutex);
+ }
+}
+
void kvm_s390_gisa_destroy(struct kvm *kvm)
{
struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int;
+ struct kvm_s390_gisa *gisa = gi->origin;
if (!gi->origin)
return;
@@ -3183,6 +3206,25 @@ void kvm_s390_gisa_destroy(struct kvm *kvm)
cpu_relax();
hrtimer_cancel(&gi->timer);
gi->origin = NULL;
+ VM_EVENT(kvm, 3, "gisa 0x%pK destroyed", gisa);
+}
+
+void kvm_s390_gisa_disable(struct kvm *kvm)
+{
+ struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int;
+ struct kvm_vcpu *vcpu;
+ unsigned long i;
+
+ if (!gi->origin)
+ return;
+ kvm_for_each_vcpu(i, vcpu, kvm) {
+ mutex_lock(&vcpu->mutex);
+ vcpu->arch.sie_block->eca &= ~ECA_AIV;
+ vcpu->arch.sie_block->gd = 0U;
+ mutex_unlock(&vcpu->mutex);
+ VCPU_EVENT(vcpu, 3, "AIV disabled for cpu %03u", vcpu->vcpu_id);
+ }
+ kvm_s390_gisa_destroy(kvm);
}
/**
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 48e52837bc48..cd2f8ed0621d 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2224,6 +2224,9 @@ static int kvm_s390_cpus_from_pv(struct kvm *kvm, u16 *rcp, u16 *rrcp)
}
mutex_unlock(&vcpu->mutex);
}
+ /* Ensure that we re-enable gisa if the non-PV guest used it but the PV guest did not. */
+ if (use_gisa)
+ kvm_s390_gisa_enable(kvm);
return ret;
}
@@ -2234,6 +2237,10 @@ static int kvm_s390_cpus_to_pv(struct kvm *kvm, u16 *rc, u16 *rrc)
struct kvm_vcpu *vcpu;
+ /* Disable the GISA if the ultravisor does not support AIV. */
+ if (!test_bit_inv(BIT_UV_FEAT_AIV, &uv_info.uv_feature_indications))
+ kvm_s390_gisa_disable(kvm);
+
kvm_for_each_vcpu(i, vcpu, kvm) {
mutex_lock(&vcpu->mutex);
r = kvm_s390_pv_create_cpu(vcpu, rc, rrc);
@@ -3394,9 +3401,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
vcpu->arch.sie_block->icpua = vcpu->vcpu_id;
spin_lock_init(&vcpu->arch.local_int.lock);
- vcpu->arch.sie_block->gd = (u32)(u64)vcpu->kvm->arch.gisa_int.origin;
- if (vcpu->arch.sie_block->gd && sclp.has_gisaf)
- vcpu->arch.sie_block->gd |= GISA_FORMAT1;
+ vcpu->arch.sie_block->gd = kvm_s390_get_gisa_desc(vcpu->kvm);
seqcount_init(&vcpu->arch.cputm_seqcount);
vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID;
diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 1876ab0c293f..dfc7de6b01a8 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -217,6 +217,15 @@ static inline void kvm_s390_set_user_cpu_state_ctrl(struct kvm *kvm)
kvm->arch.user_cpu_state_ctrl = 1;
}
+static inline u32 kvm_s390_get_gisa_desc(struct kvm *kvm)
+{
+ u32 gd = (u32)(u64)kvm->arch.gisa_int.origin;
+
+ if (gd && sclp.has_gisaf)
+ gd |= GISA_FORMAT1;
+ return gd;
+}
+
/* implemented in pv.c */
int kvm_s390_pv_destroy_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc);
int kvm_s390_pv_create_cpu(struct kvm_vcpu *vcpu, u16 *rc, u16 *rrc);
@@ -436,6 +445,8 @@ int kvm_s390_get_irq_state(struct kvm_vcpu *vcpu,
void kvm_s390_gisa_init(struct kvm *kvm);
void kvm_s390_gisa_clear(struct kvm *kvm);
void kvm_s390_gisa_destroy(struct kvm *kvm);
+void kvm_s390_gisa_disable(struct kvm *kvm);
+void kvm_s390_gisa_enable(struct kvm *kvm);
int kvm_s390_gib_init(u8 nisc);
void kvm_s390_gib_destroy(void);
--
2.25.1
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