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authorDavid Hildenbrand <dahi@linux.vnet.ibm.com>2016-05-27 22:03:52 +0200
committerChristian Borntraeger <borntraeger@de.ibm.com>2016-06-21 09:43:44 +0200
commitadbf16985c387851fd3454ca34893705dbde7f98 (patch)
treeda60441f03e9b218ea1a8f822b46558c2da92756 /arch/s390
parentKVM: s390: vsie: try to refault after a reported fault to g2 (diff)
downloadlinux-adbf16985c387851fd3454ca34893705dbde7f98.tar.xz
linux-adbf16985c387851fd3454ca34893705dbde7f98.zip
KVM: s390: vsie: speed up VCPU irq delivery when handling vsie
Whenever we want to wake up a VCPU (e.g. when injecting an IRQ), we have to kick it out of vsie, so the request will be handled faster. Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/include/asm/kvm_host.h2
-rw-r--r--arch/s390/kvm/interrupt.c5
-rw-r--r--arch/s390/kvm/kvm-s390.h1
-rw-r--r--arch/s390/kvm/vsie.c35
4 files changed, 43 insertions, 0 deletions
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 190ad63291fb..946fc86202fd 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -549,6 +549,8 @@ struct kvm_guestdbg_info_arch {
struct kvm_vcpu_arch {
struct kvm_s390_sie_block *sie_block;
+ /* if vsie is active, currently executed shadow sie control block */
+ struct kvm_s390_sie_block *vsie_block;
unsigned int host_acrs[NUM_ACRS];
struct fpu host_fpregs;
struct kvm_s390_local_interrupt local_int;
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index d72c4a877622..ca19627779db 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -995,6 +995,11 @@ void kvm_s390_vcpu_wakeup(struct kvm_vcpu *vcpu)
swake_up(&vcpu->wq);
vcpu->stat.halt_wakeup++;
}
+ /*
+ * The VCPU might not be sleeping but is executing the VSIE. Let's
+ * kick it, so it leaves the SIE to process the request.
+ */
+ kvm_s390_vsie_kick(vcpu);
}
enum hrtimer_restart kvm_s390_idle_wakeup(struct hrtimer *timer)
diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index b137fbaac91c..ffbbdd285385 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -254,6 +254,7 @@ int kvm_s390_handle_eb(struct kvm_vcpu *vcpu);
/* implemented in vsie.c */
int kvm_s390_handle_vsie(struct kvm_vcpu *vcpu);
+void kvm_s390_vsie_kick(struct kvm_vcpu *vcpu);
void kvm_s390_vsie_gmap_notifier(struct gmap *gmap, unsigned long start,
unsigned long end);
void kvm_s390_vsie_init(struct kvm *kvm);
diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
index 7482488d21d0..c8c8763e7822 100644
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -838,6 +838,23 @@ static int acquire_gmap_shadow(struct kvm_vcpu *vcpu,
}
/*
+ * Register the shadow scb at the VCPU, e.g. for kicking out of vsie.
+ */
+static void register_shadow_scb(struct kvm_vcpu *vcpu,
+ struct vsie_page *vsie_page)
+{
+ WRITE_ONCE(vcpu->arch.vsie_block, &vsie_page->scb_s);
+}
+
+/*
+ * Unregister a shadow scb from a VCPU.
+ */
+static void unregister_shadow_scb(struct kvm_vcpu *vcpu)
+{
+ WRITE_ONCE(vcpu->arch.vsie_block, NULL);
+}
+
+/*
* Run the vsie on a shadowed scb, managing the gmap shadow, handling
* prefix pages and faults.
*
@@ -860,6 +877,7 @@ static int vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
rc = do_vsie_run(vcpu, vsie_page);
gmap_enable(vcpu->arch.gmap);
}
+ atomic_andnot(PROG_BLOCK_SIE, &scb_s->prog20);
if (rc == -EAGAIN)
rc = 0;
@@ -1000,7 +1018,9 @@ int kvm_s390_handle_vsie(struct kvm_vcpu *vcpu)
rc = pin_blocks(vcpu, vsie_page);
if (rc)
goto out_unshadow;
+ register_shadow_scb(vcpu, vsie_page);
rc = vsie_run(vcpu, vsie_page);
+ unregister_shadow_scb(vcpu);
unpin_blocks(vcpu, vsie_page);
out_unshadow:
unshadow_scb(vcpu, vsie_page);
@@ -1039,3 +1059,18 @@ void kvm_s390_vsie_destroy(struct kvm *kvm)
kvm->arch.vsie.page_count = 0;
mutex_unlock(&kvm->arch.vsie.mutex);
}
+
+void kvm_s390_vsie_kick(struct kvm_vcpu *vcpu)
+{
+ struct kvm_s390_sie_block *scb = READ_ONCE(vcpu->arch.vsie_block);
+
+ /*
+ * Even if the VCPU lets go of the shadow sie block reference, it is
+ * still valid in the cache. So we can safely kick it.
+ */
+ if (scb) {
+ atomic_or(PROG_BLOCK_SIE, &scb->prog20);
+ if (scb->prog0c & PROG_IN_SIE)
+ atomic_or(CPUSTAT_STOP_INT, &scb->cpuflags);
+ }
+}