The state of the thread interrupt management registers needs to be
collected for migration. These registers are cached under the
'xive_saved_state.w01' field of the VCPU when the VPCU context is
pulled from the HW thread. An OPAL call retrieves the backup of the
IPB register in the underlying XIVE NVT structure and merges it in the
KVM state.
Signed-off-by: Cédric Le Goater <clg@xxxxxxxx>
Reviewed-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
---
Changes since v3 :
- Fixed xive_timaval description in documentation
Changes since v2 :
- reduced the size of kvmppc_one_reg timaval attribute to two u64s
- stopped returning of the OS CAM line value
arch/powerpc/include/asm/kvm_ppc.h | 11 ++++
arch/powerpc/include/uapi/asm/kvm.h | 2 +
arch/powerpc/kvm/book3s.c | 24 +++++++
arch/powerpc/kvm/book3s_xive_native.c | 76 ++++++++++++++++++++++
Documentation/virtual/kvm/devices/xive.txt | 17 +++++
5 files changed, 130 insertions(+)
diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index 6928a35ac3c7..0579c9b253db 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -273,6 +273,7 @@ union kvmppc_one_reg {
u64 addr;
u64 length;
} vpaval;
+ u64 xive_timaval[2];
};
struct kvmppc_ops {
@@ -605,6 +606,10 @@ extern int kvmppc_xive_native_connect_vcpu(struct kvm_device *dev,
extern void kvmppc_xive_native_cleanup_vcpu(struct kvm_vcpu *vcpu);
extern void kvmppc_xive_native_init_module(void);
extern void kvmppc_xive_native_exit_module(void);
+extern int kvmppc_xive_native_get_vp(struct kvm_vcpu *vcpu,
+ union kvmppc_one_reg *val);
+extern int kvmppc_xive_native_set_vp(struct kvm_vcpu *vcpu,
+ union kvmppc_one_reg *val);
#else
static inline int kvmppc_xive_set_xive(struct kvm *kvm, u32 irq, u32 server,
@@ -637,6 +642,12 @@ static inline int kvmppc_xive_native_connect_vcpu(struct kvm_device *dev,
static inline void kvmppc_xive_native_cleanup_vcpu(struct kvm_vcpu *vcpu) { }
static inline void kvmppc_xive_native_init_module(void) { }
static inline void kvmppc_xive_native_exit_module(void) { }
+static inline int kvmppc_xive_native_get_vp(struct kvm_vcpu *vcpu,
+ union kvmppc_one_reg *val)
+{ return 0; }
+static inline int kvmppc_xive_native_set_vp(struct kvm_vcpu *vcpu,
+ union kvmppc_one_reg *val)
+{ return -ENOENT; }
#endif /* CONFIG_KVM_XIVE */
diff --git a/arch/powerpc/include/uapi/asm/kvm.h b/arch/powerpc/include/uapi/asm/kvm.h
index 12744608a61c..cd3f16b70a2e 100644
--- a/arch/powerpc/include/uapi/asm/kvm.h
+++ b/arch/powerpc/include/uapi/asm/kvm.h
@@ -482,6 +482,8 @@ struct kvm_ppc_cpu_char {
#define KVM_REG_PPC_ICP_PPRI_SHIFT 16 /* pending irq priority */
#define KVM_REG_PPC_ICP_PPRI_MASK 0xff
+#define KVM_REG_PPC_VP_STATE (KVM_REG_PPC | KVM_REG_SIZE_U128 | 0x8d)
+
/* Device control API: PPC-specific devices */
#define KVM_DEV_MPIC_GRP_MISC 1
#define KVM_DEV_MPIC_BASE_ADDR 0 /* 64-bit */
diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c
index 7c3348fa27e1..efd15101eef0 100644
--- a/arch/powerpc/kvm/book3s.c
+++ b/arch/powerpc/kvm/book3s.c
@@ -651,6 +651,18 @@ int kvmppc_get_one_reg(struct kvm_vcpu *vcpu, u64 id,
*val = get_reg_val(id, kvmppc_xics_get_icp(vcpu));
break;
#endif /* CONFIG_KVM_XICS */
+#ifdef CONFIG_KVM_XIVE
+ case KVM_REG_PPC_VP_STATE:
+ if (!vcpu->arch.xive_vcpu) {
+ r = -ENXIO;
+ break;
+ }
+ if (xive_enabled())
+ r = kvmppc_xive_native_get_vp(vcpu, val);
+ else
+ r = -ENXIO;
+ break;
+#endif /* CONFIG_KVM_XIVE */
case KVM_REG_PPC_FSCR:
*val = get_reg_val(id, vcpu->arch.fscr);
break;
@@ -724,6 +736,18 @@ int kvmppc_set_one_reg(struct kvm_vcpu *vcpu, u64 id,
r = kvmppc_xics_set_icp(vcpu, set_reg_val(id, *val));
break;
#endif /* CONFIG_KVM_XICS */
+#ifdef CONFIG_KVM_XIVE
+ case KVM_REG_PPC_VP_STATE:
+ if (!vcpu->arch.xive_vcpu) {
+ r = -ENXIO;
+ break;
+ }
+ if (xive_enabled())
+ r = kvmppc_xive_native_set_vp(vcpu, val);
+ else
+ r = -ENXIO;
+ break;
+#endif /* CONFIG_KVM_XIVE */
case KVM_REG_PPC_FSCR:
vcpu->arch.fscr = set_reg_val(id, *val);
break;
diff --git a/arch/powerpc/kvm/book3s_xive_native.c b/arch/powerpc/kvm/book3s_xive_native.c
index 44ce74086550..a8c62e07ebee 100644
--- a/arch/powerpc/kvm/book3s_xive_native.c
+++ b/arch/powerpc/kvm/book3s_xive_native.c
@@ -889,6 +889,82 @@ static int kvmppc_xive_native_create(struct kvm_device *dev, u32 type)
return ret;
}
+/*
+ * Interrupt Pending Buffer (IPB) offset
+ */
+#define TM_IPB_SHIFT 40
+#define TM_IPB_MASK (((u64) 0xFF) << TM_IPB_SHIFT)
+
+int kvmppc_xive_native_get_vp(struct kvm_vcpu *vcpu, union kvmppc_one_reg *val)
+{
+ struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
+ u64 opal_state;
+ int rc;
+
+ if (!kvmppc_xive_enabled(vcpu))
+ return -EPERM;
+
+ if (!xc)
+ return -ENOENT;
+
+ /* Thread context registers. We only care about IPB and CPPR */
+ val->xive_timaval[0] = vcpu->arch.xive_saved_state.w01;
+
+ /* Get the VP state from OPAL */
+ rc = xive_native_get_vp_state(xc->vp_id, &opal_state);
+ if (rc)
+ return rc;
+
+ /*
+ * Capture the backup of IPB register in the NVT structure and
+ * merge it in our KVM VP state.
+ */
+ val->xive_timaval[0] |= cpu_to_be64(opal_state & TM_IPB_MASK);
+
+ pr_devel("%s NSR=%02x CPPR=%02x IBP=%02x PIPR=%02x w01=%016llx w2=%08x opal=%016llx\n",
+ __func__,
+ vcpu->arch.xive_saved_state.nsr,
+ vcpu->arch.xive_saved_state.cppr,
+ vcpu->arch.xive_saved_state.ipb,
+ vcpu->arch.xive_saved_state.pipr,
+ vcpu->arch.xive_saved_state.w01,
+ (u32) vcpu->arch.xive_cam_word, opal_state);
+
+ return 0;
+}
+
+int kvmppc_xive_native_set_vp(struct kvm_vcpu *vcpu, union kvmppc_one_reg *val)
+{
+ struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
+ struct kvmppc_xive *xive = vcpu->kvm->arch.xive;
+
+ pr_devel("%s w01=%016llx vp=%016llx\n", __func__,
+ val->xive_timaval[0], val->xive_timaval[1]);
+
+ if (!kvmppc_xive_enabled(vcpu))
+ return -EPERM;
+
+ if (!xc || !xive)
+ return -ENOENT;
+
+ /* We can't update the state of a "pushed" VCPU */
+ if (WARN_ON(vcpu->arch.xive_pushed))
+ return -EBUSY;
+
+ /*
+ * Restore the thread context registers. IPB and CPPR should
+ * be the only ones that matter.
+ */
+ vcpu->arch.xive_saved_state.w01 = val->xive_timaval[0];
+
+ /*
+ * There is no need to restore the XIVE internal state (IPB
+ * stored in the NVT) as the IPB register was merged in KVM VP
+ * state when captured.
+ */
+ return 0;
+}
+
static int xive_native_debug_show(struct seq_file *m, void *private)
{
struct kvmppc_xive *xive = m->private;
diff --git a/Documentation/virtual/kvm/devices/xive.txt b/Documentation/virtual/kvm/devices/xive.txt
index 278bc653cfdc..702836d5ad7a 100644
--- a/Documentation/virtual/kvm/devices/xive.txt
+++ b/Documentation/virtual/kvm/devices/xive.txt
@@ -107,6 +107,23 @@ the legacy interrupt mode, referred as XICS (POWER7/8).
-ENOENT: Unknown source number
-EINVAL: Not initialized source number
+* VCPU state
+
+ The XIVE IC maintains VP interrupt state in an internal structure
+ called the NVT. When a VP is not dispatched on a HW processor
+ thread, this structure can be updated by HW if the VP is the target
+ of an event notification.
+
+ It is important for migration to capture the cached IPB from the NVT
+ as it synthesizes the priorities of the pending interrupts. We
+ capture a bit more to report debug information.
+
+ KVM_REG_PPC_VP_STATE (2 * 64bits)
+ bits: | 63 .... 32 | 31 .... 0 |
+ values: | TIMA word0 | TIMA word1 |
+ bits: | 127 .......... 64 |
+ values: | unused |
+
* Migration:
Saving the state of a VM using the XIVE native exploitation mode
--
2.20.1
