linux-kernel - [PATCH v10 09/19] KVM: s390: pv: Add kvm_s390_cpus_from

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Message-Id: <20220414080311.1084834-10-imbrenda@linux.ibm.com>
Date:   Thu, 14 Apr 2022 10:03:00 +0200
From:   Claudio Imbrenda <imbrenda@...ux.ibm.com>
To:     kvm@...r.kernel.org
Cc:     borntraeger@...ibm.com, frankja@...ux.ibm.com, thuth@...hat.com,
        pasic@...ux.ibm.com, david@...hat.com, linux-s390@...r.kernel.org,
        linux-kernel@...r.kernel.org, scgl@...ux.ibm.com,
        mimu@...ux.ibm.com, nrb@...ux.ibm.com
Subject: [PATCH v10 09/19] KVM: s390: pv: Add kvm_s390_cpus_from_pv to kvm-s390.h and add documentation

Future changes make it necessary to call this function from pv.c.

While we are at it, let's properly document kvm_s390_cpus_from_pv() and
kvm_s390_cpus_to_pv().

Signed-off-by: Claudio Imbrenda <imbrenda@...ux.ibm.com>
Reviewed-by: Janosch Frank <frankja@...ux.ibm.com>
---
 arch/s390/kvm/kvm-s390.c | 26 +++++++++++++++++++++++++-
 arch/s390/kvm/kvm-s390.h |  1 +
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index c7a8829e852c..ed55e2a89635 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2175,7 +2175,20 @@ static int kvm_s390_set_cmma_bits(struct kvm *kvm,
 	return r;
 }
 
-static int kvm_s390_cpus_from_pv(struct kvm *kvm, u16 *rcp, u16 *rrcp)
+/**
+ * kvm_s390_cpus_from_pv - Convert all protected vCPUs in a protected VM to
+ * non protected.
+ * @kvm the VM whose protected vCPUs are to be converted
+ * @rcp return value for the RC field of the UVC (in case of error)
+ * @rrcp return value for the RRC field of the UVC (in case of error)
+ *
+ * Does not stop in case of error, tries to convert as many
+ * CPUs as possible. In case of error, the RC and RRC of the last error are
+ * returned.
+ *
+ * Return: 0 in case of success, otherwise -EIO
+ */
+int kvm_s390_cpus_from_pv(struct kvm *kvm, u16 *rcp, u16 *rrcp)
 {
 	struct kvm_vcpu *vcpu;
 	u16 rc, rrc;
@@ -2205,6 +2218,17 @@ static int kvm_s390_cpus_from_pv(struct kvm *kvm, u16 *rcp, u16 *rrcp)
 	return ret;
 }
 
+/**
+ * kvm_s390_cpus_to_pv - Convert all non-protected vCPUs in a protected VM
+ * to protected.
+ * @kvm the VM whose protected vCPUs are to be converted
+ * @rcp return value for the RC field of the UVC (in case of error)
+ * @rrcp return value for the RRC field of the UVC (in case of error)
+ *
+ * Tries to undo the conversion in case of error.
+ *
+ * Return: 0 in case of success, otherwise -EIO
+ */
 static int kvm_s390_cpus_to_pv(struct kvm *kvm, u16 *rc, u16 *rrc)
 {
 	unsigned long i;
diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 497d52a83c78..d3abedafa7a8 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -374,6 +374,7 @@ int kvm_s390_vcpu_setup_cmma(struct kvm_vcpu *vcpu);
 void kvm_s390_vcpu_unsetup_cmma(struct kvm_vcpu *vcpu);
 void kvm_s390_set_cpu_timer(struct kvm_vcpu *vcpu, __u64 cputm);
 __u64 kvm_s390_get_cpu_timer(struct kvm_vcpu *vcpu);
+int kvm_s390_cpus_from_pv(struct kvm *kvm, u16 *rcp, u16 *rrcp);
 
 /* implemented in diag.c */
 int kvm_s390_handle_diag(struct kvm_vcpu *vcpu);
-- 
2.34.1