3 files changed, 279 insertions, 0 deletions

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index de54f14e081e..1d00aead6bc5 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2271,6 +2271,68 @@ static ssize_t kvm_s390_handle_pv_info(struct kvm_s390_pv_info *info)
 	}
 }
 
+static int kvm_s390_pv_dmp(struct kvm *kvm, struct kvm_pv_cmd *cmd,
+			   struct kvm_s390_pv_dmp dmp)
+{
+	int r = -EINVAL;
+	void __user *result_buff = (void __user *)dmp.buff_addr;
+
+	switch (dmp.subcmd) {
+	case KVM_PV_DUMP_INIT: {
+		if (kvm->arch.pv.dumping)
+			break;
+
+		/*
+		 * Block SIE entry as concurrent dump UVCs could lead
+		 * to validities.
+		 */
+		kvm_s390_vcpu_block_all(kvm);
+
+		r = uv_cmd_nodata(kvm_s390_pv_get_handle(kvm),
+				  UVC_CMD_DUMP_INIT, &cmd->rc, &cmd->rrc);
+		KVM_UV_EVENT(kvm, 3, "PROTVIRT DUMP INIT: rc %x rrc %x",
+			     cmd->rc, cmd->rrc);
+		if (!r) {
+			kvm->arch.pv.dumping = true;
+		} else {
+			kvm_s390_vcpu_unblock_all(kvm);
+			r = -EINVAL;
+		}
+		break;
+	}
+	case KVM_PV_DUMP_CONFIG_STOR_STATE: {
+		if (!kvm->arch.pv.dumping)
+			break;
+
+		/*
+		 * gaddr is an output parameter since we might stop
+		 * early. As dmp will be copied back in our caller, we
+		 * don't need to do it ourselves.
+		 */
+		r = kvm_s390_pv_dump_stor_state(kvm, result_buff, &dmp.gaddr, dmp.buff_len,
+						&cmd->rc, &cmd->rrc);
+		break;
+	}
+	case KVM_PV_DUMP_COMPLETE: {
+		if (!kvm->arch.pv.dumping)
+			break;
+
+		r = -EINVAL;
+		if (dmp.buff_len < uv_info.conf_dump_finalize_len)
+			break;
+
+		r = kvm_s390_pv_dump_complete(kvm, result_buff,
+					      &cmd->rc, &cmd->rrc);
+		break;
+	}
+	default:
+		r = -ENOTTY;
+		break;
+	}
+
+	return r;
+}
+
 static int kvm_s390_handle_pv(struct kvm *kvm, struct kvm_pv_cmd *cmd)
 {
 	int r = 0;
@@ -2447,6 +2509,28 @@ static int kvm_s390_handle_pv(struct kvm *kvm, struct kvm_pv_cmd *cmd)
 		r = 0;
 		break;
 	}
+	case KVM_PV_DUMP: {
+		struct kvm_s390_pv_dmp dmp;
+
+		r = -EINVAL;
+		if (!kvm_s390_pv_is_protected(kvm))
+			break;
+
+		r = -EFAULT;
+		if (copy_from_user(&dmp, argp, sizeof(dmp)))
+			break;
+
+		r = kvm_s390_pv_dmp(kvm, cmd, dmp);
+		if (r)
+			break;
+
+		if (copy_to_user(argp, &dmp, sizeof(dmp))) {
+			r = -EFAULT;
+			break;
+		}
+
+		break;
+	}
 	default:
 		r = -ENOTTY;
 	}
@@ -4564,6 +4648,15 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 	struct kvm_run *kvm_run = vcpu->run;
 	int rc;
 
+	/*
+	 * Running a VM while dumping always has the potential to
+	 * produce inconsistent dump data. But for PV vcpus a SIE
+	 * entry while dumping could also lead to a fatal validity
+	 * intercept which we absolutely want to avoid.
+	 */
+	if (vcpu->kvm->arch.pv.dumping)
+		return -EINVAL;
+
 	if (kvm_run->immediate_exit)
 		return -EINTR;
 
diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 497d52a83c78..2c11eb5ba3ef 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -250,6 +250,10 @@ int kvm_s390_pv_set_sec_parms(struct kvm *kvm, void *hdr, u64 length, u16 *rc,
 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_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,
+			      u16 *rc, u16 *rrc);
 
 static inline u64 kvm_s390_pv_get_handle(struct kvm *kvm)
 {
diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c
index cc7c9599f43e..e9912113879c 100644
--- a/arch/s390/kvm/pv.c
+++ b/arch/s390/kvm/pv.c
@@ -7,6 +7,7 @@
  */
 #include <linux/kvm.h>
 #include <linux/kvm_host.h>
+#include <linux/minmax.h>
 #include <linux/pagemap.h>
 #include <linux/sched/signal.h>
 #include <asm/gmap.h>
@@ -298,3 +299,184 @@ int kvm_s390_pv_set_cpu_state(struct kvm_vcpu *vcpu, u8 state)
 		return -EINVAL;
 	return 0;
 }
+
+/* Size of the cache for the storage state dump data. 1MB for now */
+#define DUMP_BUFF_LEN HPAGE_SIZE
+
+/**
+ * kvm_s390_pv_dump_stor_state
+ *
+ * @kvm: pointer to the guest's KVM struct
+ * @buff_user: Userspace pointer where we will write the results to
+ * @gaddr: Starting absolute guest address for which the storage state
+ *	   is requested.
+ * @buff_user_len: Length of the buff_user buffer
+ * @rc: Pointer to where the uvcb return code is stored
+ * @rrc: Pointer to where the uvcb return reason code is stored
+ *
+ * Stores buff_len bytes of tweak component values to buff_user
+ * starting with the 1MB block specified by the absolute guest address
+ * (gaddr). The gaddr pointer will be updated with the last address
+ * for which data was written when returning to userspace. buff_user
+ * might be written to even if an error rc is returned. For instance
+ * if we encounter a fault after writing the first page of data.
+ *
+ * Context: kvm->lock needs to be held
+ *
+ * Return:
+ *  0 on success
+ *  -ENOMEM if allocating the cache fails
+ *  -EINVAL if gaddr is not aligned to 1MB
+ *  -EINVAL if buff_user_len is not aligned to uv_info.conf_dump_storage_state_len
+ *  -EINVAL if the UV call fails, rc and rrc will be set in this case
+ *  -EFAULT if copying the result to buff_user failed
+ */
+int kvm_s390_pv_dump_stor_state(struct kvm *kvm, void __user *buff_user,
+				u64 *gaddr, u64 buff_user_len, u16 *rc, u16 *rrc)
+{
+	struct uv_cb_dump_stor_state uvcb = {
+		.header.cmd = UVC_CMD_DUMP_CONF_STOR_STATE,
+		.header.len = sizeof(uvcb),
+		.config_handle = kvm->arch.pv.handle,
+		.gaddr = *gaddr,
+		.dump_area_origin = 0,
+	};
+	const u64 increment_len = uv_info.conf_dump_storage_state_len;
+	size_t buff_kvm_size;
+	size_t size_done = 0;
+	u8 *buff_kvm = NULL;
+	int cc, ret;
+
+	ret = -EINVAL;
+	/* UV call processes 1MB guest storage chunks at a time */
+	if (!IS_ALIGNED(*gaddr, HPAGE_SIZE))
+		goto out;
+
+	/*
+	 * We provide the storage state for 1MB chunks of guest
+	 * storage. The buffer will need to be aligned to
+	 * conf_dump_storage_state_len so we don't end on a partial
+	 * chunk.
+	 */
+	if (!buff_user_len ||
+	    !IS_ALIGNED(buff_user_len, increment_len))
+		goto out;
+
+	/*
+	 * Allocate a buffer from which we will later copy to the user
+	 * process. We don't want userspace to dictate our buffer size
+	 * so we limit it to DUMP_BUFF_LEN.
+	 */
+	ret = -ENOMEM;
+	buff_kvm_size = min_t(u64, buff_user_len, DUMP_BUFF_LEN);
+	buff_kvm = vzalloc(buff_kvm_size);
+	if (!buff_kvm)
+		goto out;
+
+	ret = 0;
+	uvcb.dump_area_origin = (u64)buff_kvm;
+	/* We will loop until the user buffer is filled or an error occurs */
+	do {
+		/* Get 1MB worth of guest storage state data */
+		cc = uv_call_sched(0, (u64)&uvcb);
+
+		/* All or nothing */
+		if (cc) {
+			ret = -EINVAL;
+			break;
+		}
+
+		size_done += increment_len;
+		uvcb.dump_area_origin += increment_len;
+		buff_user_len -= increment_len;
+		uvcb.gaddr += HPAGE_SIZE;
+
+		/* KVM Buffer full, time to copy to the process */
+		if (!buff_user_len || size_done == DUMP_BUFF_LEN) {
+			if (copy_to_user(buff_user, buff_kvm, size_done)) {
+				ret = -EFAULT;
+				break;
+			}
+
+			buff_user += size_done;
+			size_done = 0;
+			uvcb.dump_area_origin = (u64)buff_kvm;
+		}
+	} while (buff_user_len);
+
+	/* Report back where we ended dumping */
+	*gaddr = uvcb.gaddr;
+
+	/* Lets only log errors, we don't want to spam */
+out:
+	if (ret)
+		KVM_UV_EVENT(kvm, 3,
+			     "PROTVIRT DUMP STORAGE STATE: addr %llx ret %d, uvcb rc %x rrc %x",
+			     uvcb.gaddr, ret, uvcb.header.rc, uvcb.header.rrc);
+	*rc = uvcb.header.rc;
+	*rrc = uvcb.header.rrc;
+	vfree(buff_kvm);
+
+	return ret;
+}
+
+/**
+ * kvm_s390_pv_dump_complete
+ *
+ * @kvm: pointer to the guest's KVM struct
+ * @buff_user: Userspace pointer where we will write the results to
+ * @rc: Pointer to where the uvcb return code is stored
+ * @rrc: Pointer to where the uvcb return reason code is stored
+ *
+ * Completes the dumping operation and writes the completion data to
+ * user space.
+ *
+ * Context: kvm->lock needs to be held
+ *
+ * Return:
+ *  0 on success
+ *  -ENOMEM if allocating the completion buffer fails
+ *  -EINVAL if the UV call fails, rc and rrc will be set in this case
+ *  -EFAULT if copying the result to buff_user failed
+ */
+int kvm_s390_pv_dump_complete(struct kvm *kvm, void __user *buff_user,
+			      u16 *rc, u16 *rrc)
+{
+	struct uv_cb_dump_complete complete = {
+		.header.len = sizeof(complete),
+		.header.cmd = UVC_CMD_DUMP_COMPLETE,
+		.config_handle = kvm_s390_pv_get_handle(kvm),
+	};
+	u64 *compl_data;
+	int ret;
+
+	/* Allocate dump area */
+	compl_data = vzalloc(uv_info.conf_dump_finalize_len);
+	if (!compl_data)
+		return -ENOMEM;
+	complete.dump_area_origin = (u64)compl_data;
+
+	ret = uv_call_sched(0, (u64)&complete);
+	*rc = complete.header.rc;
+	*rrc = complete.header.rrc;
+	KVM_UV_EVENT(kvm, 3, "PROTVIRT DUMP COMPLETE: rc %x rrc %x",
+		     complete.header.rc, complete.header.rrc);
+
+	if (!ret) {
+		/*
+		 * kvm_s390_pv_dealloc_vm() will also (mem)set
+		 * this to false on a reboot or other destroy
+		 * operation for this vm.
+		 */
+		kvm->arch.pv.dumping = false;
+		kvm_s390_vcpu_unblock_all(kvm);
+		ret = copy_to_user(buff_user, compl_data, uv_info.conf_dump_finalize_len);
+		if (ret)
+			ret = -EFAULT;
+	}
+	vfree(compl_data);
+	/* If the UVC returned an error, translate it to -EINVAL */
+	if (ret > 0)
+		ret = -EINVAL;
+	return ret;
+}