From: Janosch Frank <frankja@linux.ibm.com>
Date: Tue, 17 May 2022 16:36:25 +0000
Subject: KVM: s390: Add CPU dump functionality
Git-commit: 8aba09588d2af37c6cc1a781b87d1d91ebf389ae
Patch-mainline: v6.0-rc1
References: jsc#PED-622

The previous patch introduced the per-VM dump functions now let's
focus on dumping the VCPU state via the newly introduced
KVM_S390_PV_CPU_COMMAND ioctl which mirrors the VM UV ioctl and can be
extended with new commands later.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Link: https://lore.kernel.org/r/20220517163629.3443-8-frankja@linux.ibm.com
Message-Id: <20220517163629.3443-8-frankja@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 arch/s390/kvm/kvm-s390.c |   69 +++++++++++++++++++++++++++++++++++++++++++++++
 arch/s390/kvm/kvm-s390.h |    1 
 arch/s390/kvm/pv.c       |   16 ++++++++++
 include/uapi/linux/kvm.h |    4 ++
 4 files changed, 90 insertions(+)

--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -5121,6 +5121,48 @@ long kvm_arch_vcpu_async_ioctl(struct fi
 	return -ENOIOCTLCMD;
 }
 
+static int kvm_s390_handle_pv_vcpu_dump(struct kvm_vcpu *vcpu,
+					struct kvm_pv_cmd *cmd)
+{
+	struct kvm_s390_pv_dmp dmp;
+	void *data;
+	int ret;
+
+	/* Dump initialization is a prerequisite */
+	if (!vcpu->kvm->arch.pv.dumping)
+		return -EINVAL;
+
+	if (copy_from_user(&dmp, (__u8 __user *)cmd->data, sizeof(dmp)))
+		return -EFAULT;
+
+	/* We only handle this subcmd right now */
+	if (dmp.subcmd != KVM_PV_DUMP_CPU)
+		return -EINVAL;
+
+	/* CPU dump length is the same as create cpu storage donation. */
+	if (dmp.buff_len != uv_info.guest_cpu_stor_len)
+		return -EINVAL;
+
+	data = kvzalloc(uv_info.guest_cpu_stor_len, GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	ret = kvm_s390_pv_dump_cpu(vcpu, data, &cmd->rc, &cmd->rrc);
+
+	VCPU_EVENT(vcpu, 3, "PROTVIRT DUMP CPU %d rc %x rrc %x",
+		   vcpu->vcpu_id, cmd->rc, cmd->rrc);
+
+	if (ret)
+		ret = -EINVAL;
+
+	/* On success copy over the dump data */
+	if (!ret && copy_to_user((__u8 __user *)dmp.buff_addr, data, uv_info.guest_cpu_stor_len))
+		ret = -EFAULT;
+
+	kvfree(data);
+	return ret;
+}
+
 long kvm_arch_vcpu_ioctl(struct file *filp,
 			 unsigned int ioctl, unsigned long arg)
 {
@@ -5285,6 +5327,33 @@ long kvm_arch_vcpu_ioctl(struct file *fi
 					   irq_state.len);
 		break;
 	}
+	case KVM_S390_PV_CPU_COMMAND: {
+		struct kvm_pv_cmd cmd;
+
+		r = -EINVAL;
+		if (!is_prot_virt_host())
+			break;
+
+		r = -EFAULT;
+		if (copy_from_user(&cmd, argp, sizeof(cmd)))
+			break;
+
+		r = -EINVAL;
+		if (cmd.flags)
+			break;
+
+		/* We only handle this cmd right now */
+		if (cmd.cmd != KVM_PV_DUMP)
+			break;
+
+		r = kvm_s390_handle_pv_vcpu_dump(vcpu, &cmd);
+
+		/* Always copy over UV rc / rrc data */
+		if (copy_to_user((__u8 __user *)argp, &cmd.rc,
+				 sizeof(cmd.rc) + sizeof(cmd.rrc)))
+			r = -EFAULT;
+		break;
+	}
 	default:
 		r = -ENOTTY;
 	}
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -227,6 +227,7 @@ int kvm_s390_pv_set_sec_parms(struct kvm
 int kvm_s390_pv_unpack(struct kvm *kvm, unsigned long addr, unsigned long size,
 		       unsigned long tweak, u16 *rc, u16 *rrc);
 int kvm_s390_pv_set_cpu_state(struct kvm_vcpu *vcpu, u8 state);
+int kvm_s390_pv_dump_cpu(struct kvm_vcpu *vcpu, void *buff, u16 *rc, u16 *rrc);
 int kvm_s390_pv_dump_stor_state(struct kvm *kvm, void __user *buff_user,
 				u64 *gaddr, u64 buff_user_len, u16 *rc, u16 *rrc);
 int kvm_s390_pv_dump_complete(struct kvm *kvm, void __user *buff_user,
--- a/arch/s390/kvm/pv.c
+++ b/arch/s390/kvm/pv.c
@@ -307,6 +307,22 @@ int kvm_s390_pv_set_cpu_state(struct kvm
 	return 0;
 }
 
+int kvm_s390_pv_dump_cpu(struct kvm_vcpu *vcpu, void *buff, u16 *rc, u16 *rrc)
+{
+	struct uv_cb_dump_cpu uvcb = {
+		.header.cmd = UVC_CMD_DUMP_CPU,
+		.header.len = sizeof(uvcb),
+		.cpu_handle = vcpu->arch.pv.handle,
+		.dump_area_origin = (u64)buff,
+	};
+	int cc;
+
+	cc = uv_call_sched(0, (u64)&uvcb);
+	*rc = uvcb.header.rc;
+	*rrc = uvcb.header.rrc;
+	return cc;
+}
+
 /* Size of the cache for the storage state dump data. 1MB for now */
 #define DUMP_BUFF_LEN HPAGE_SIZE
 
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1609,6 +1609,7 @@ enum pv_cmd_dmp_id {
 	KVM_PV_DUMP_INIT,
 	KVM_PV_DUMP_CONFIG_STOR_STATE,
 	KVM_PV_DUMP_COMPLETE,
+	KVM_PV_DUMP_CPU,
 };
 
 struct kvm_s390_pv_dmp {
@@ -2062,4 +2063,7 @@ struct kvm_stats_desc {
 
 #define KVM_GET_STATS_FD  _IO(KVMIO,  0xce)
 
+/* Available with KVM_CAP_S390_PROTECTED_DUMP */
+#define KVM_S390_PV_CPU_COMMAND	_IOWR(KVMIO, 0xd0, struct kvm_pv_cmd)
+
 #endif /* __LINUX_KVM_H */