[Qemu-ppc] [PATCH] Revert "target-ppc/kvm: Enable in-kernel TCE acceleration for multi-tce"

[Jose Ricardo Ziviani]

This reverts commit 3dc410ae83e6cb76c81ea30a05d62596092b3165.

Booting a radix guest in Power9 with that commit throws a host kernel
oops:

[17582052553.360178] Unable to handle kernel paging request for data at address 
0xe64bb17da64ab078
[17582052553.360420] Faulting instruction address: 0xc0000000002c3ddc
[17582052553.360533] Oops: Kernel access of bad area, sig: 11 [#1]
[17582052553.360643] SMP NR_CPUS=1024
[17582052553.360645] NUMA
[17582052553.360712] PowerNV
[17582052553.360804] Modules linked in: vhost_net vhost tap xt_CHECKSUM 
ipt_MASQUERADE nf_nat_masquerade_ipv4 ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 
nf_conntrack_ipv6 nf_defrag_ipv6 xt_conntrack ip_set nfnetlink ebtable_nat 
ebtable_broute bridge stp llc ip6table_mangle ip6table_security ip6table_raw 
iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack 
libcrc32c iptable_mangle iptable_security iptable_raw ebtable_filter ebtables 
ip6table_filter ip6_tables ses enclosure scsi_transport_sas ipmi_powernv 
powernv_op_panel ipmi_devintf ipmi_msghandler nfsd kvm_hv auth_rpcgss 
oid_registry nfs_acl lockd grace sunrpc kvm tg3 ptp pps_core
[17582052553.361797] CPU: 5 PID: 4966 Comm: qemu-system-ppc Not tainted 
4.11.0-1.git4a6869a.el7.centos.ppc64le #1
[17582052553.361972] task: c0000003c5e90a80 task.stack: c0000003c5f6c000
[17582052553.362082] NIP: c0000000002c3ddc LR: c0000000002c3e80 CTR: 
c0000000000ce2e0
[17582052553.362214] REGS: c0000003c5f6f150 TRAP: 0380   Not tainted  
(4.11.0-1.git4a6869a.el7.centos.ppc64le)
[17582052553.362467] MSR: 9000000000001031 <SF,HV,ME,IR,DR,LE>
[17582052553.362480]   CR: 44008024  XER: 20000000
[17582052553.362822] CFAR: c0000000002c3e7c SOFTE: 1
[17582052553.362822] GPR00: 000000000000018f c0000003c5f6f3d0 c00000000131fd00 
0000000000000000
[17582052553.362822] GPR04: 0000000000000005 00000000000001ff 0000000000000000 
7db04aa67db14ba6
[17582052553.362822] GPR08: 264bb17da64ab000 e64bb17da64ab000 0000000000000078 
0000000000000000
[17582052553.362822] GPR12: c0000003bdb98008 c00000000fdc2d00 c00000000000e148 
0000000000000000
[17582052553.362822] GPR16: 0000000008000000 0000000020000000 0000000000000000 
c0000003c5f6f4c0
[17582052553.362822] GPR20: c0000001ffff9440 c0000001fd033280 c0000001fd0342a0 
c0000001f24efff8
[17582052553.362822] GPR24: 0000000000000200 00000001f24f0000 0000000000000010 
0000000000020000
[17582052553.362822] GPR28: 0800000000000000 00000001f24f0000 000000007db04aa6 
00000000a64ab07d
[17582052553.365148] NIP [c0000000002c3ddc] vmalloc_to_page+0x19c/0x220
[17582052553.365365] LR [c0000000002c3e80] vmalloc_to_pfn+0x20/0x50
[17582052553.365582] Call Trace:
[17582052553.365720] [c0000003c5f6f3d0] [7265677368657265] 0x7265677368657265 
(unreliable)
[17582052553.365982] [c0000003c5f6f400] [c0000000002c3e80] 
vmalloc_to_pfn+0x20/0x50
[17582052553.366245] [c0000003c5f6f420] [c0000000000637e8] 
vmalloc_to_phys+0x28/0x60
[17582052553.366508] [c0000003c5f6f450] [c0000000000ce480] 
kvmppc_rm_h_put_tce_indirect+0x1a0/0x540
[17582052553.366812] [c0000003c5f6f590] [c0000000000d0314] 
hcall_try_real_mode+0x60/0x7c
[17582052553.367074] [c0000003c5f6f600] [c0000000000cefac] 
kvmppc_call_hv_entry+0x8/0x17c
[17582052553.367346] [c0000003c5f6f670] [c00800000375a970] 
__kvmppc_vcore_entry+0x13c/0x1ac [kvm_hv]
[17582052553.367652] [c0000003c5f6f840] [c0080000037574a8] 
kvmppc_run_core+0x788/0x1650 [kvm_hv]
[17582052553.367965] [c0000003c5f6fa00] [c0080000037590b8] 
kvmppc_vcpu_run_hv+0x388/0x1200 [kvm_hv]
[17582052553.368287] [c0000003c5f6fb30] [c008000003274684] 
kvmppc_vcpu_run+0x34/0x50 [kvm]
[17582052553.368558] [c0000003c5f6fb50] [c008000003270b54] 
kvm_arch_vcpu_ioctl_run+0x114/0x2a0 [kvm]
[17582052553.368870] [c0000003c5f6fbd0] [c008000003263dd8] 
kvm_vcpu_ioctl+0x5e8/0x7c0 [kvm]
[17582052553.369132] [c0000003c5f6fd40] [c000000000350b50] 
do_vfs_ioctl+0xd0/0x8c0
[17582052553.369395] [c0000003c5f6fde0] [c000000000351414] SyS_ioctl+0xd4/0xf0
[17582052553.369615] [c0000003c5f6fe30] [c00000000000b8e0] system_call+0x38/0xfc
[17582052553.369875] Instruction dump:
[17582052553.370011] 53dfc42e 790807c6 394affff 7d08fb78 78638402 79081764 
7d4a07b4 7c6a5038
[17582052553.370281] 7908f5e6 7d094b78 794a1f24 38600000 <7d2a482a> 7924cfe3 
41820040 79260022
[17582052553.370599] ---[ end trace 9470442ed18ae727 ]---

As soon as we identify and fix the issue that's causing such problem
I'll re-send the referred patch to re-enable TCE.

Signed-off-by: Jose Ricardo Ziviani <address@hidden>
CC: Bharata B Rao <address@hidden>
---
 hw/ppc/spapr.c       |  4 +---
 target/ppc/kvm.c     | 14 --------------
 target/ppc/kvm_ppc.h |  6 ------
 3 files changed, 1 insertion(+), 23 deletions(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index e2dc77c..362ee81 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -2340,12 +2340,10 @@ static void ppc_spapr_init(MachineState *machine)
 
     qemu_register_boot_set(spapr_boot_set, spapr);
 
+    /* to stop and start vmclock */
     if (kvm_enabled()) {
-        /* to stop and start vmclock */
         qemu_add_vm_change_state_handler(cpu_ppc_clock_vm_state_change,
                                          &spapr->tb);
-
-        kvmppc_spapr_enable_inkernel_multitce();
     }
 }
 
diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
index 8574c36..c959b90 100644
--- a/target/ppc/kvm.c
+++ b/target/ppc/kvm.c
@@ -2198,20 +2198,6 @@ bool kvmppc_spapr_use_multitce(void)
     return cap_spapr_multitce;
 }
 
-int kvmppc_spapr_enable_inkernel_multitce(void)
-{
-    int ret;
-
-    ret = kvm_vm_enable_cap(kvm_state, KVM_CAP_PPC_ENABLE_HCALL, 0,
-                            H_PUT_TCE_INDIRECT, 1);
-    if (!ret) {
-        ret = kvm_vm_enable_cap(kvm_state, KVM_CAP_PPC_ENABLE_HCALL, 0,
-                                H_STUFF_TCE, 1);
-    }
-
-    return ret;
-}
-
 void *kvmppc_create_spapr_tce(uint32_t liobn, uint32_t page_shift,
                               uint64_t bus_offset, uint32_t nb_table,
                               int *pfd, bool need_vfio)
diff --git a/target/ppc/kvm_ppc.h b/target/ppc/kvm_ppc.h
index f48243d..4b2fd9a 100644
--- a/target/ppc/kvm_ppc.h
+++ b/target/ppc/kvm_ppc.h
@@ -39,7 +39,6 @@ target_ulong kvmppc_configure_v3_mmu(PowerPCCPU *cpu,
 #ifndef CONFIG_USER_ONLY
 off_t kvmppc_alloc_rma(void **rma);
 bool kvmppc_spapr_use_multitce(void);
-int kvmppc_spapr_enable_inkernel_multitce(void);
 void *kvmppc_create_spapr_tce(uint32_t liobn, uint32_t page_shift,
                               uint64_t bus_offset, uint32_t nb_table,
                               int *pfd, bool need_vfio);
@@ -181,11 +180,6 @@ static inline bool kvmppc_spapr_use_multitce(void)
     return false;
 }
 
-static inline int kvmppc_spapr_enable_inkernel_multitce(void)
-{
-    return -1;
-}
-
 static inline void *kvmppc_create_spapr_tce(uint32_t liobn, uint32_t 
page_shift,
                                             uint64_t bus_offset,
                                             uint32_t nb_table,
-- 
2.7.4