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From 3c8c0e5bae7be14972cd38c470227d7037892a2c Mon Sep 17 00:00:00 2001
From: David Gibson <dgibson@redhat.com>
Date: Mon, 12 Nov 2018 01:28:35 +0000
Subject: [PATCH 04/16] ppc/spapr_caps: Add SPAPR_CAP_NESTED_KVM_HV

RH-Author: David Gibson <dgibson@redhat.com>
Message-id: <20181112012835.21863-5-dgibson@redhat.com>
Patchwork-id: 82980
O-Subject: [RHEL-8 qemu-kvm PATCH 4/4] ppc/spapr_caps: Add SPAPR_CAP_NESTED_KVM_HV
Bugzilla: 1639069
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
RH-Acked-by: Serhii Popovych <spopovyc@redhat.com>
RH-Acked-by: Thomas Huth <thuth@redhat.com>

From: Suraj Jitindar Singh <sjitindarsingh@gmail.com>

Add the spapr cap SPAPR_CAP_NESTED_KVM_HV to be used to control the
availability of nested kvm-hv to the level 1 (L1) guest.

Assuming a hypervisor with support enabled an L1 guest can be allowed to
use the kvm-hv module (and thus run it's own kvm-hv guests) by setting:
-machine pseries,cap-nested-hv=true
or disabled with:
-machine pseries,cap-nested-hv=false

Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
(cherry picked from commit b9a477b725788e47bf653eab36e64f232d259f2a)
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>

Conflicts:
	hw/ppc/spapr.c
	hw/ppc/spapr_caps.c
	include/hw/ppc/spapr.h

We need some tweaks to renumber the nested KVM cap from upstream,
because we don't have the maximum page size capability downstream and
the code doesn't like sparse cap numbers.  This is safe, because the
cap number does not appear in the migration stream, so it's strictly
local (the cap name is used for migration).

We also work around a contextual conflict.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1639069

Signed-off-by: David Gibson <dgibson@redhat.com>
---
 hw/ppc/spapr.c         |  2 ++
 hw/ppc/spapr_caps.c    | 32 ++++++++++++++++++++++++++++++++
 include/hw/ppc/spapr.h |  5 ++++-
 target/ppc/kvm.c       | 12 ++++++++++++
 target/ppc/kvm_ppc.h   | 12 ++++++++++++
 5 files changed, 62 insertions(+), 1 deletion(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index a61dafd..ea72782 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1816,6 +1816,7 @@ static const VMStateDescription vmstate_spapr = {
         &vmstate_spapr_cap_cfpc,
         &vmstate_spapr_cap_sbbc,
         &vmstate_spapr_cap_ibs,
+        &vmstate_spapr_cap_nested_kvm_hv,
         NULL
     }
 };
@@ -3922,6 +3923,7 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
     smc->default_caps.caps[SPAPR_CAP_CFPC] = SPAPR_CAP_BROKEN;
     smc->default_caps.caps[SPAPR_CAP_SBBC] = SPAPR_CAP_BROKEN;
     smc->default_caps.caps[SPAPR_CAP_IBS] = SPAPR_CAP_BROKEN;
+    smc->default_caps.caps[SPAPR_CAP_NESTED_KVM_HV] = SPAPR_CAP_OFF;
     spapr_caps_add_properties(smc, &error_abort);
     smc->has_power9_support = true;
 }
diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c
index 00e43a9..86a7947 100644
--- a/hw/ppc/spapr_caps.c
+++ b/hw/ppc/spapr_caps.c
@@ -265,6 +265,28 @@ static void cap_safe_indirect_branch_apply(sPAPRMachineState *spapr,
 
 #define VALUE_DESC_TRISTATE     " (broken, workaround, fixed)"
 
+static void cap_nested_kvm_hv_apply(sPAPRMachineState *spapr,
+                                    uint8_t val, Error **errp)
+{
+    if (!val) {
+        /* capability disabled by default */
+        return;
+    }
+
+    if (tcg_enabled()) {
+        error_setg(errp,
+                   "No Nested KVM-HV support in tcg, try cap-nested-hv=off");
+    } else if (kvm_enabled()) {
+        if (!kvmppc_has_cap_nested_kvm_hv()) {
+            error_setg(errp,
+"KVM implementation does not support Nested KVM-HV, try cap-nested-hv=off");
+        } else if (kvmppc_set_cap_nested_kvm_hv(val) < 0) {
+                error_setg(errp,
+"Error enabling cap-nested-hv with KVM, try cap-nested-hv=off");
+        }
+    }
+}
+
 sPAPRCapabilityInfo capability_table[SPAPR_CAP_NUM] = {
     [SPAPR_CAP_HTM] = {
         .name = "htm",
@@ -324,6 +346,15 @@ sPAPRCapabilityInfo capability_table[SPAPR_CAP_NUM] = {
         .possible = &cap_ibs_possible,
         .apply = cap_safe_indirect_branch_apply,
     },
+    [SPAPR_CAP_NESTED_KVM_HV] = {
+        .name = "nested-hv",
+        .description = "Allow Nested KVM-HV",
+        .index = SPAPR_CAP_NESTED_KVM_HV,
+        .get = spapr_cap_get_bool,
+        .set = spapr_cap_set_bool,
+        .type = "bool",
+        .apply = cap_nested_kvm_hv_apply,
+    },
 };
 
 static sPAPRCapabilities default_caps_with_cpu(sPAPRMachineState *spapr,
@@ -439,6 +470,7 @@ SPAPR_CAP_MIG_STATE(dfp, SPAPR_CAP_DFP);
 SPAPR_CAP_MIG_STATE(cfpc, SPAPR_CAP_CFPC);
 SPAPR_CAP_MIG_STATE(sbbc, SPAPR_CAP_SBBC);
 SPAPR_CAP_MIG_STATE(ibs, SPAPR_CAP_IBS);
+SPAPR_CAP_MIG_STATE(nested_kvm_hv, SPAPR_CAP_NESTED_KVM_HV);
 
 void spapr_caps_reset(sPAPRMachineState *spapr)
 {
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 5118af6..beb42bc 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -66,8 +66,10 @@ typedef enum {
 #define SPAPR_CAP_SBBC                  0x04
 /* Indirect Branch Serialisation */
 #define SPAPR_CAP_IBS                   0x05
+/* Nested KVM-HV */
+#define SPAPR_CAP_NESTED_KVM_HV         0x06
 /* Num Caps */
-#define SPAPR_CAP_NUM                   (SPAPR_CAP_IBS + 1)
+#define SPAPR_CAP_NUM                   (SPAPR_CAP_NESTED_KVM_HV + 1)
 
 /*
  * Capability Values
@@ -794,6 +796,7 @@ extern const VMStateDescription vmstate_spapr_cap_dfp;
 extern const VMStateDescription vmstate_spapr_cap_cfpc;
 extern const VMStateDescription vmstate_spapr_cap_sbbc;
 extern const VMStateDescription vmstate_spapr_cap_ibs;
+extern const VMStateDescription vmstate_spapr_cap_nested_kvm_hv;
 
 static inline uint8_t spapr_get_cap(sPAPRMachineState *spapr, int cap)
 {
diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
index 192c40d..058dcbe 100644
--- a/target/ppc/kvm.c
+++ b/target/ppc/kvm.c
@@ -92,6 +92,7 @@ static int cap_ppc_pvr_compat;
 static int cap_ppc_safe_cache;
 static int cap_ppc_safe_bounds_check;
 static int cap_ppc_safe_indirect_branch;
+static int cap_ppc_nested_kvm_hv;
 
 static uint32_t debug_inst_opcode;
 
@@ -152,6 +153,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
     cap_mmu_hash_v3 = kvm_vm_check_extension(s, KVM_CAP_PPC_MMU_HASH_V3);
     cap_resize_hpt = kvm_vm_check_extension(s, KVM_CAP_SPAPR_RESIZE_HPT);
     kvmppc_get_cpu_characteristics(s);
+    cap_ppc_nested_kvm_hv = kvm_vm_check_extension(s, KVM_CAP_PPC_NESTED_HV);
     /*
      * Note: setting it to false because there is not such capability
      * in KVM at this moment.
@@ -2552,6 +2554,16 @@ int kvmppc_get_cap_safe_indirect_branch(void)
     return cap_ppc_safe_indirect_branch;
 }
 
+bool kvmppc_has_cap_nested_kvm_hv(void)
+{
+    return !!cap_ppc_nested_kvm_hv;
+}
+
+int kvmppc_set_cap_nested_kvm_hv(int enable)
+{
+    return kvm_vm_enable_cap(kvm_state, KVM_CAP_PPC_NESTED_HV, 0, enable);
+}
+
 bool kvmppc_has_cap_spapr_vfio(void)
 {
     return cap_spapr_vfio;
diff --git a/target/ppc/kvm_ppc.h b/target/ppc/kvm_ppc.h
index 4d2789e..dc86eff 100644
--- a/target/ppc/kvm_ppc.h
+++ b/target/ppc/kvm_ppc.h
@@ -63,6 +63,8 @@ bool kvmppc_has_cap_mmu_hash_v3(void);
 int kvmppc_get_cap_safe_cache(void);
 int kvmppc_get_cap_safe_bounds_check(void);
 int kvmppc_get_cap_safe_indirect_branch(void);
+bool kvmppc_has_cap_nested_kvm_hv(void);
+int kvmppc_set_cap_nested_kvm_hv(int enable);
 int kvmppc_enable_hwrng(void);
 int kvmppc_put_books_sregs(PowerPCCPU *cpu);
 PowerPCCPUClass *kvm_ppc_get_host_cpu_class(void);
@@ -314,6 +316,16 @@ static inline int kvmppc_get_cap_safe_indirect_branch(void)
     return 0;
 }
 
+static inline bool kvmppc_has_cap_nested_kvm_hv(void)
+{
+    return false;
+}
+
+static inline int kvmppc_set_cap_nested_kvm_hv(int enable)
+{
+    return -1;
+}
+
 static inline int kvmppc_enable_hwrng(void)
 {
     return -1;
-- 
1.8.3.1