From c0af45c7da067bc9679b0b491971b026e5722876 Mon Sep 17 00:00:00 2001

From: David Gibson <dgibson@redhat.com>

Date: Thu, 27 Apr 2017 02:15:58 +0200

Subject: [PATCH 23/23] spapr: Workaround for broken radix guests

RH-Author: David Gibson <dgibson@redhat.com>

Message-id: <20170427021558.4884-8-dgibson@redhat.com>

Patchwork-id: 74920

O-Subject: [Pegas-1.0 qemu-kvm-rhev PATCH 7/7] spapr: Workaround for broken radix guests

Bugzilla: 1368786

RH-Acked-by: Thomas Huth <thuth@redhat.com>

RH-Acked-by: Laurent Vivier <lvivier@redhat.com>

RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

From: Sam Bobroff <sam.bobroff@au1.ibm.com>

For a little while around 4.9, Linux kernels that saw the radix bit in

ibm,pa-features would attempt to set up the MMU as if they were a

hypervisor, even if they were a guest, which would cause them to

crash.

Work around this by detecting pre-ISA 3.0 guests by their lack of that

bit in option vector 1, and then removing the radix bit from

ibm,pa-features. Note: This now requires regeneration of that node

after CAS negotiation.

Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>

[dwg: Fix style nits]

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

(cherry picked from commit e957f6a9b92439a222ecd4ff1c8cdc9700710c72)

Siged-off-by: David Gibson <dgibson@redhat.com>

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 hw/ppc/spapr.c              | 15 +++++++++++++--

 hw/ppc/spapr_hcall.c        |  6 ++++--

 include/hw/ppc/spapr.h      |  1 +

 include/hw/ppc/spapr_ovec.h |  3 +++

 4 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c

index 5a5196a..cc3ccc1 100644

--- a/hw/ppc/spapr.c

+++ b/hw/ppc/spapr.c

@@ -228,7 +228,8 @@ static int spapr_fixup_cpu_numa_dt(void *fdt, int offset, CPUState *cs)

 }

 /* Populate the "ibm,pa-features" property */

-static void spapr_populate_pa_features(CPUPPCState *env, void *fdt, int offset)

+static void spapr_populate_pa_features(CPUPPCState *env, void *fdt, int offset,

+                                      bool legacy_guest)

 {

     uint8_t pa_features_206[] = { 6, 0,

         0xf6, 0x1f, 0xc7, 0x00, 0x80, 0xc0 };

@@ -295,6 +296,12 @@ static void spapr_populate_pa_features(CPUPPCState *env, void *fdt, int offset)

     if (kvmppc_has_cap_htm() && pa_size > 24) {

         pa_features[24] |= 0x80;    /* Transactional memory support */

     }

+    if (legacy_guest && pa_size > 40) {

+        /* Workaround for broken kernels that attempt (guest) radix

+         * mode when they can't handle it, if they see the radix bit set

+         * in pa-features. So hide it from them. */

+        pa_features[40 + 2] &= ~0x80; /* Radix MMU */

+    }

     _FDT((fdt_setprop(fdt, offset, "ibm,pa-features", pa_features, pa_size)));

 }

@@ -309,6 +316,7 @@ static int spapr_fixup_cpu_dt(void *fdt, sPAPRMachineState *spapr)

     CPU_FOREACH(cs) {

         PowerPCCPU *cpu = POWERPC_CPU(cs);

+        CPUPPCState *env = &cpu->env;

         DeviceClass *dc = DEVICE_GET_CLASS(cs);

         int index = ppc_get_vcpu_dt_id(cpu);

         int compat_smt = MIN(smp_threads, ppc_compat_max_threads(cpu));

@@ -350,6 +358,9 @@ static int spapr_fixup_cpu_dt(void *fdt, sPAPRMachineState *spapr)

         if (ret < 0) {

             return ret;

         }

+

+        spapr_populate_pa_features(env, fdt, offset,

+                                         spapr->cas_legacy_guest_workaround);

     }

     return ret;

 }

@@ -547,7 +558,7 @@ static void spapr_populate_cpu_dt(CPUState *cs, void *fdt, int offset,

                           page_sizes_prop, page_sizes_prop_size)));

     }

-    spapr_populate_pa_features(env, fdt, offset);

+    spapr_populate_pa_features(env, fdt, offset, false);

     _FDT((fdt_setprop_cell(fdt, offset, "ibm,chip-id",

                            cs->cpu_index / vcpus_per_socket)));

diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c

index cbd1f29..9f18f75 100644

--- a/hw/ppc/spapr_hcall.c

+++ b/hw/ppc/spapr_hcall.c

@@ -1062,7 +1062,7 @@ static target_ulong h_client_architecture_support(PowerPCCPU *cpu,

     uint32_t max_compat = cpu->max_compat;

     uint32_t best_compat = 0;

     int i;

-    sPAPROptionVector *ov5_guest, *ov5_cas_old, *ov5_updates;

+    sPAPROptionVector *ov1_guest, *ov5_guest, *ov5_cas_old, *ov5_updates;

     bool guest_radix;

     /*

@@ -1114,6 +1114,7 @@ static target_ulong h_client_architecture_support(PowerPCCPU *cpu,

     /* For the future use: here @ov_table points to the first option vector */

     ov_table = list;

+    ov1_guest = spapr_ovec_parse_vector(ov_table, 1);

     ov5_guest = spapr_ovec_parse_vector(ov_table, 5);

     if (spapr_ovec_test(ov5_guest, OV5_MMU_BOTH)) {

         error_report("guest requested hash and radix MMU, which is invalid.");

@@ -1155,7 +1156,8 @@ static target_ulong h_client_architecture_support(PowerPCCPU *cpu,

             exit(EXIT_FAILURE);

         }

     }

-

+    spapr->cas_legacy_guest_workaround = !spapr_ovec_test(ov1_guest,

+                                                          OV1_PPC_3_00);

     if (!spapr->cas_reboot) {

         spapr->cas_reboot =

             (spapr_h_cas_compose_response(spapr, args[1], args[2],

diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h

index 247c969..a6ef8cb 100644

--- a/include/hw/ppc/spapr.h

+++ b/include/hw/ppc/spapr.h

@@ -77,6 +77,7 @@ struct sPAPRMachineState {

     sPAPROptionVector *ov5;         /* QEMU-supported option vectors */

     sPAPROptionVector *ov5_cas;     /* negotiated (via CAS) option vectors */

     bool cas_reboot;

+    bool cas_legacy_guest_workaround;

     Notifier epow_notifier;

     QTAILQ_HEAD(, sPAPREventLogEntry) pending_events;

diff --git a/include/hw/ppc/spapr_ovec.h b/include/hw/ppc/spapr_ovec.h

index f7f2abe..f088833 100644

--- a/include/hw/ppc/spapr_ovec.h

+++ b/include/hw/ppc/spapr_ovec.h

@@ -43,6 +43,9 @@ typedef struct sPAPROptionVector sPAPROptionVector;

 #define OV_BIT(byte, bit) ((byte - 1) * BITS_PER_BYTE + bit)

+/* option vector 1 */

+#define OV1_PPC_3_00            OV_BIT(3, 0) /* guest supports PowerPC 3.00? */

+

 /* option vector 5 */

 #define OV5_DRCONF_MEMORY       OV_BIT(2, 2)

 #define OV5_FORM1_AFFINITY      OV_BIT(5, 0)

-- 

1.8.3.1