On 31.10.18 09:23, Christian Borntraeger wrote:
On 10/25/2018 02:37 PM, Michael Mueller wrote:
The GIB (Guest Information Block) links the GISA of all guests
that have adapter interrupts pending. These interrupts cannot be
deliverd because no vcpu of these guests is currently running in
SIE context. Instead, a GIB alert is issued on the host to schedule
these guests to run.
This mechanism allows to process adapter interrupts for currently
not running guests.
The GIB is created during host initialization and associated with
the Adapter Interruption Facility in case an Adapter Interruption
Virtualization Facility is available.
Signed-off-by: Michael Mueller <mimu@xxxxxxxxxxxxx>
Some small nits below.
Other than that
Reviewed-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
arch/s390/include/asm/kvm_host.h | 10 ++++++++
arch/s390/kvm/interrupt.c | 43 ++++++++++++++++++++++++++++++++
arch/s390/kvm/kvm-s390.c | 1 +
arch/s390/kvm/kvm-s390.h | 2 ++
4 files changed, 56 insertions(+)
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 29c940bf8506..01be3b666b11 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -776,6 +776,15 @@ struct kvm_s390_gisa {
};
};
+struct kvm_s390_gib {
+ atomic_t alert_list_origin;
The only place that touches this is patch 5 (setting it to 0). All other activities
are done by HW and that is why we need an atomic update.
atomic_t does work as of today but you never know if we add some debugging code in the
future that makes atomic_t bigger. Can we maybe just use an u32 here and then use cmpxchg
in patch5?
replaced by type u32 and using macro cmpxchg which itself uses built-in
__sync_val_compare_and_swap
+ u32 reserved01;
+ u8:5;
+ u8 nisc:3;
+ u8 reserved03[3];
+ u32 reserved04[5];
+};
+
/*
* sie_page2 has to be allocated as DMA because fac_list, crycb and
* gisa need 31bit addresses in the sie control block.
@@ -829,6 +838,7 @@ struct kvm_arch{
/* subset of available cpu features enabled by user space */
DECLARE_BITMAP(cpu_feat, KVM_S390_VM_CPU_FEAT_NR_BITS);
struct kvm_s390_gisa *gisa;
+ int gib_in_use;
};
i>
#define KVM_HVA_ERR_BAD (-1UL)
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index fcb55b02990e..3789a9ad8dee 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -31,6 +31,8 @@
#define PFAULT_DONE 0x0680
#define VIRTIO_PARAM 0x0d00
+static struct kvm_s390_gib *gib;
+
/* handle external calls via sigp interpretation facility */
static int sca_ext_call_pending(struct kvm_vcpu *vcpu, int *src_id)
{
@@ -2899,6 +2901,7 @@ void kvm_s390_gisa_init(struct kvm *kvm)
kvm->arch.gisa = &kvm->arch.sie_page2->gisa;
VM_EVENT(kvm, 3, "gisa 0x%pK initialized", kvm->arch.gisa);
kvm_s390_gisa_clear(kvm);
+ kvm->arch.gib_in_use = !!gib;
}
}
@@ -2908,3 +2911,43 @@ void kvm_s390_gisa_destroy(struct kvm *kvm)
return;
kvm->arch.gisa = NULL;
}
+
+void kvm_s390_gib_destroy(void)
+{
+ if (!gib)
+ return;
+ chsc_sgib(0);
+ free_page((unsigned long)gib);
+ gib = NULL;
+}
+
+void kvm_s390_gib_init(u8 nisc)
+{
+ int rc;
+
+ if (gib)
+ return;
+
+ if (!css_general_characteristics.aiv) {
+ KVM_EVENT(3, "%s", "gib not initialized, no AIV facility");
+ return;
+ }
+
+ gib = (struct kvm_s390_gib *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
+ if (!gib) {
+ KVM_EVENT(3, "%s", "gib memory allocation failed");
+ return;
+ }
+
+ gib->nisc = nisc;
+ rc = chsc_sgib((u32)(u64)gib);
+ if (rc) {
You could get rid of rc by doing
if (chsc_sgib((u32)(u64)gib))
changed that as well
+ KVM_EVENT(3, "gib 0x%pK AIV association failed rc: %d",
+ gib, rc);
+ free_page((unsigned long)gib);
+ gib = NULL;
+ return;
+ }
+
+ KVM_EVENT(3, "gib 0x%pK (nisc=%d) initialized", gib, gib->nisc);
+}
[...]
