KVM: s390: Add CPU dump functionality

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>

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 1d00aead6bc5b11d89238489e3b7aa060c35d671..37be2a33edb52f1b8766672bed1e546dacf30c72 100644 (file)
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -5096,6 +5096,48 @@ long kvm_arch_vcpu_async_ioctl(struct file *filp,
        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)
 {
@@ -5260,6 +5302,33 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
                                           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;
        }

diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 2c11eb5ba3ef30dc6622862aaede8d23b9df854e..dd01d989816f0b428a1ac4e9c56d14277fd01749 100644 (file)
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -250,6 +250,7 @@ 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_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,

diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c
index e9912113879c139c6ced4750a0ce22b2a0f2404f..b4a499b10b672bb7c390b2a454d2792cc826f909 100644 (file)
--- a/arch/s390/kvm/pv.c
+++ b/arch/s390/kvm/pv.c
@@ -300,6 +300,22 @@ int kvm_s390_pv_set_cpu_state(struct kvm_vcpu *vcpu, u8 state)
        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
 

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 673be2061c6c70cb1edd2a2fc02beff09ee94365..af5d254f80619b800ac4671f85fe238a7c0dc974 100644 (file)
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1664,6 +1664,7 @@ 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 {
@@ -2168,4 +2169,7 @@ struct kvm_stats_desc {
 /* Available with KVM_CAP_XSAVE2 */
 #define KVM_GET_XSAVE2           _IOR(KVMIO,  0xcf, struct kvm_xsave)
 
+/* Available with KVM_CAP_S390_PROTECTED_DUMP */
+#define KVM_S390_PV_CPU_COMMAND        _IOWR(KVMIO, 0xd0, struct kvm_pv_cmd)
+
 #endif /* __LINUX_KVM_H */