From: David Hildenbrand <dahi@linux.vnet.ibm.com>
Date: Wed, 4 Nov 2015 15:46:55 +0000 (+0100)
Subject: KVM: s390: irq delivery should not rely on icptcode
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=eaa4f41642f096f1e10c15a2b172d79199e893ff;p=linux.git

KVM: s390: irq delivery should not rely on icptcode

Program irq injection during program irq intercepts is the last candidates
that injects nullifying irqs and relies on delivery to do the right thing.

As we should not rely on the icptcode during any delivery (because that
value will not be migrated), let's add a flag, telling prog IRQ delivery
to not rewind the PSW in case of nullifying prog IRQs.

Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---

diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
index 6b4e5b5ff06ca..2e6b54e4d3f95 100644
--- a/arch/s390/kvm/intercept.c
+++ b/arch/s390/kvm/intercept.c
@@ -140,6 +140,8 @@ static int inject_prog_on_prog_intercept(struct kvm_vcpu *vcpu)
 {
 	struct kvm_s390_pgm_info pgm_info = {
 		.code = vcpu->arch.sie_block->iprcc,
+		/* the PSW has already been rewound */
+		.flags = KVM_S390_PGM_FLAGS_NO_REWIND,
 	};
 
 	switch (vcpu->arch.sie_block->iprcc & ~PGM_PER) {
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index e594a78300222..87e2d1a89d74e 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -665,7 +665,7 @@ static int __must_check __deliver_prog(struct kvm_vcpu *vcpu)
 				   (u8 *) __LC_PER_ACCESS_ID);
 	}
 
-	if (nullifying && vcpu->arch.sie_block->icptcode == ICPT_INST)
+	if (nullifying && !(pgm_info.flags & KVM_S390_PGM_FLAGS_NO_REWIND))
 		kvm_s390_rewind_psw(vcpu, ilen);
 
 	/* bit 1+2 of the target are the ilc, so we can directly use ilen */
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 4e20a40bb10f5..a2fe0ac1d61ac 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -545,6 +545,7 @@ struct kvm_s390_pgm_info {
 #define KVM_S390_PGM_FLAGS_ILC_0	0x02
 #define KVM_S390_PGM_FLAGS_ILC_1	0x04
 #define KVM_S390_PGM_FLAGS_ILC_MASK	0x06
+#define KVM_S390_PGM_FLAGS_NO_REWIND	0x08
 	__u8 flags;
 	__u8 pad[2];
 };