diff mbox series

[RFC,09/10] ppc/pnv: Implement POWER10 PC xscom registers for direct controls

Message ID 20240526122612.473476-10-npiggin@gmail.com
State New
Headers show
Series ppc/pnv: Better big-core model, lpar-per-core, PC unit | expand

Commit Message

Nicholas Piggin May 26, 2024, 12:26 p.m. UTC
The PC unit in the processor core contains xscom registers that provide
low level status and control of the CPU.

This implements "direct controls" sufficient for OPAL (skiboot) firmware
use, which is to stop threads and send them non-maskable IPIs in the
form of SRESET interrupts.

POWER10 is sufficiently different (particularly QME and special wakeup)
from POWER9 that it is not trivial to implement by reusing the code.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 include/hw/core/cpu.h     |  8 ++++
 include/hw/ppc/pnv.h      |  2 +
 include/hw/ppc/pnv_core.h |  3 ++
 hw/ppc/pnv.c              |  7 +++-
 hw/ppc/pnv_core.c         | 88 ++++++++++++++++++++++++++++++++++++---
 system/cpus.c             | 10 +++++
 6 files changed, 112 insertions(+), 6 deletions(-)

Comments

Cédric Le Goater May 29, 2024, 7 a.m. UTC | #1
On 5/26/24 14:26, Nicholas Piggin wrote:
> The PC unit in the processor core contains xscom registers that provide
> low level status and control of the CPU.
> 
> This implements "direct controls" sufficient for OPAL (skiboot) firmware
> use, which is to stop threads and send them non-maskable IPIs in the
> form of SRESET interrupts.
> 
> POWER10 is sufficiently different (particularly QME and special wakeup)
> from POWER9 that it is not trivial to implement by reusing the code.
> 
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
>   include/hw/core/cpu.h     |  8 ++++
>   include/hw/ppc/pnv.h      |  2 +
>   include/hw/ppc/pnv_core.h |  3 ++
>   hw/ppc/pnv.c              |  7 +++-
>   hw/ppc/pnv_core.c         | 88 ++++++++++++++++++++++++++++++++++++---
>   system/cpus.c             | 10 +++++
>   6 files changed, 112 insertions(+), 6 deletions(-)
> 
> diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
> index bb398e8237..52a8fc65cb 100644
> --- a/include/hw/core/cpu.h
> +++ b/include/hw/core/cpu.h
> @@ -974,6 +974,14 @@ void cpu_reset_interrupt(CPUState *cpu, int mask);
>    */
>   void cpu_exit(CPUState *cpu);
>   
> +/**
> + * cpu_pause:
> + * @cpu: The CPU to pause.
> + *
> + * Resumes CPU, i.e. puts CPU into stopped state.
> + */
> +void cpu_pause(CPUState *cpu);
> +
>   /**
>    * cpu_resume:
>    * @cpu: The CPU to resume.
> diff --git a/include/hw/ppc/pnv.h b/include/hw/ppc/pnv.h
> index 93ecb062b4..bec603f1a8 100644
> --- a/include/hw/ppc/pnv.h
> +++ b/include/hw/ppc/pnv.h
> @@ -111,6 +111,8 @@ PnvChip *pnv_chip_add_phb(PnvChip *chip, PnvPHB *phb);
>   #define PNV_FDT_ADDR          0x01000000
>   #define PNV_TIMEBASE_FREQ     512000000ULL
>   
> +void pnv_cpu_do_nmi(CPUState *cs);
> +
>   /*
>    * BMC helpers
>    */
> diff --git a/include/hw/ppc/pnv_core.h b/include/hw/ppc/pnv_core.h
> index 39f8f33e6c..9599da15ea 100644
> --- a/include/hw/ppc/pnv_core.h
> +++ b/include/hw/ppc/pnv_core.h
> @@ -109,6 +109,9 @@ OBJECT_DECLARE_TYPE(PnvQuad, PnvQuadClass, PNV_QUAD)
>   struct PnvQuad {
>       DeviceState parent_obj;
>   
> +    bool special_wakeup_done;
> +    bool special_wakeup[4];
> +
>       uint32_t quad_id;
>       MemoryRegion xscom_regs;
>       MemoryRegion xscom_qme_regs;
> diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
> index 5364c55bbb..765142965f 100644
> --- a/hw/ppc/pnv.c
> +++ b/hw/ppc/pnv.c
> @@ -2700,12 +2700,17 @@ static void pnv_cpu_do_nmi_on_cpu(CPUState *cs, run_on_cpu_data arg)
>       }
>   }
>   
> +void pnv_cpu_do_nmi(CPUState *cs)
> +{
> +    async_run_on_cpu(cs, pnv_cpu_do_nmi_on_cpu, RUN_ON_CPU_NULL);
> +}
> +
>   static void pnv_nmi(NMIState *n, int cpu_index, Error **errp)
>   {
>       CPUState *cs;
>   
>       CPU_FOREACH(cs) {
> -        async_run_on_cpu(cs, pnv_cpu_do_nmi_on_cpu, RUN_ON_CPU_NULL);
> +        pnv_cpu_do_nmi(cs);
>       }
>   }

What about ?

https://lore.kernel.org/qemu-devel/20240424093048.180966-1-clg@redhat.com/


Thanks,

C.



> diff --git a/hw/ppc/pnv_core.c b/hw/ppc/pnv_core.c
> index 10417d92ae..835c35d90b 100644
> --- a/hw/ppc/pnv_core.c
> +++ b/hw/ppc/pnv_core.c
> @@ -184,16 +184,40 @@ static const MemoryRegionOps pnv_core_power9_xscom_ops = {
>    */
>   
>   #define PNV10_XSCOM_EC_CORE_THREAD_STATE    0x412
> +#define PNV10_XSCOM_EC_CORE_THREAD_INFO     0x413
> +#define PNV10_XSCOM_EC_CORE_DIRECT_CONTROLS 0x449
> +#define PNV10_XSCOM_EC_CORE_RAS_STATUS      0x454
>   
>   static uint64_t pnv_core_power10_xscom_read(void *opaque, hwaddr addr,
>                                              unsigned int width)
>   {
> +    PnvCore *pc = PNV_CORE(opaque);
> +    int nr_threads = CPU_CORE(pc)->nr_threads;
> +    int i;
>       uint32_t offset = addr >> 3;
>       uint64_t val = 0;
>   
>       switch (offset) {
>       case PNV10_XSCOM_EC_CORE_THREAD_STATE:
> -        val = 0;
> +        for (i = 0; i < nr_threads; i++) {
> +            PowerPCCPU *cpu = pc->threads[i];
> +            CPUState *cs = CPU(cpu);
> +
> +            if (cs->halted) {
> +                val |= PPC_BIT(56 + i);
> +            }
> +        }
> +        break;
> +    case PNV10_XSCOM_EC_CORE_THREAD_INFO:
> +        break;
> +    case PNV10_XSCOM_EC_CORE_RAS_STATUS:
> +        for (i = 0; i < nr_threads; i++) {
> +            PowerPCCPU *cpu = pc->threads[i];
> +            CPUState *cs = CPU(cpu);
> +            if (cs->stopped) {
> +                val |= PPC_BIT(0 + 8*i) | PPC_BIT(1 + 8*i);
> +            }
> +        }
>           break;
>       default:
>           qemu_log_mask(LOG_UNIMP, "%s: unimp read 0x%08x\n", __func__,
> @@ -206,9 +230,45 @@ static uint64_t pnv_core_power10_xscom_read(void *opaque, hwaddr addr,
>   static void pnv_core_power10_xscom_write(void *opaque, hwaddr addr,
>                                            uint64_t val, unsigned int width)
>   {
> +    PnvCore *pc = PNV_CORE(opaque);
> +    int nr_threads = CPU_CORE(pc)->nr_threads;
> +    int i;
>       uint32_t offset = addr >> 3;
>   
>       switch (offset) {
> +    case PNV10_XSCOM_EC_CORE_DIRECT_CONTROLS:
> +        for (i = 0; i < nr_threads; i++) {
> +            PowerPCCPU *cpu = pc->threads[i];
> +            CPUState *cs = CPU(cpu);
> +
> +            if (val & PPC_BIT(7 + 8*i)) { /* stop */
> +                val &= ~PPC_BIT(7 + 8*i);
> +                cpu_pause(cs);
> +            }
> +            if (val & PPC_BIT(6 + 8*i)) { /* start */
> +                val &= ~PPC_BIT(6 + 8*i);
> +                cpu_resume(cs);
> +            }
> +            if (val & PPC_BIT(4 + 8*i)) { /* sreset */
> +                val &= ~PPC_BIT(4 + 8*i);
> +                pnv_cpu_do_nmi(cs);
> +            }
> +            if (val & PPC_BIT(3 + 8*i)) { /* clear maint */
> +                /*
> +                 * Hardware has very particular cases for where clear maint
> +                 * must be used and where start must be used to resume a
> +                 * thread. These are not modelled exactly, just treat
> +                 * this and start the same.
> +                 */
> +                val &= ~PPC_BIT(3 + 8*i);
> +                cpu_resume(cs);
> +            }
> +        }
> +        if (val) {
> +            qemu_log_mask(LOG_UNIMP, "%s: unimp bits in DIRECT_CONTROLS 0x%016lx\n", __func__, val);
> +        }
> +        break;
> +
>       default:
>           qemu_log_mask(LOG_UNIMP, "%s: unimp write 0x%08x\n", __func__,
>                         offset);
> @@ -525,6 +585,7 @@ static const MemoryRegionOps pnv_quad_power10_xscom_ops = {
>   static uint64_t pnv_qme_power10_xscom_read(void *opaque, hwaddr addr,
>                                               unsigned int width)
>   {
> +    PnvQuad *eq = PNV_QUAD(opaque);
>       uint32_t offset = addr >> 3;
>       uint64_t val = -1;
>   
> @@ -532,10 +593,14 @@ static uint64_t pnv_qme_power10_xscom_read(void *opaque, hwaddr addr,
>        * Forth nibble selects the core within a quad, mask it to process read
>        * for any core.
>        */
> -    switch (offset & ~0xf000) {
> -    case P10_QME_SPWU_HYP:
> +    switch (offset & ~PPC_BITMASK32(16, 19)) {
>       case P10_QME_SSH_HYP:
> -        return 0;
> +        val = 0;
> +        if (eq->special_wakeup_done) {
> +            val |= PPC_BIT(1); /* SPWU DONE */
> +            val |= PPC_BIT(4); /* SSH SPWU DONE */
> +        }
> +        break;
>       default:
>           qemu_log_mask(LOG_UNIMP, "%s: unimp read 0x%08x\n", __func__,
>                         offset);
> @@ -547,9 +612,22 @@ static uint64_t pnv_qme_power10_xscom_read(void *opaque, hwaddr addr,
>   static void pnv_qme_power10_xscom_write(void *opaque, hwaddr addr,
>                                            uint64_t val, unsigned int width)
>   {
> +    PnvQuad *eq = PNV_QUAD(opaque);
>       uint32_t offset = addr >> 3;
> +    bool set;
> +    int i;
>   
> -    switch (offset) {
> +    switch (offset & ~PPC_BITMASK32(16, 19)) {
> +    case P10_QME_SPWU_HYP:
> +        set = !!(val & PPC_BIT(0));
> +        eq->special_wakeup_done = set;
> +        for (i = 0; i < 4; i++) {
> +            /* These bits select cores in the quad */
> +            if (offset & PPC_BIT32(16 + i)) {
> +                eq->special_wakeup[i] = set;
> +            }
> +        }
> +        break;
>       default:
>           qemu_log_mask(LOG_UNIMP, "%s: unimp write 0x%08x\n", __func__,
>                         offset);
> diff --git a/system/cpus.c b/system/cpus.c
> index 68d161d96b..1ca18ae7ea 100644
> --- a/system/cpus.c
> +++ b/system/cpus.c
> @@ -602,6 +602,16 @@ void pause_all_vcpus(void)
>       bql_lock();
>   }
>   
> +void cpu_pause(CPUState *cpu)
> +{
> +    if (qemu_cpu_is_self(cpu)) {
> +        qemu_cpu_stop(cpu, true);
> +    } else {
> +        cpu->stop = true;
> +        qemu_cpu_kick(cpu);
> +    }
> +}
> +
>   void cpu_resume(CPUState *cpu)
>   {
>       cpu->stop = false;
Nicholas Piggin May 30, 2024, 6:53 a.m. UTC | #2
On Wed May 29, 2024 at 5:00 PM AEST, Cédric Le Goater wrote:
> On 5/26/24 14:26, Nicholas Piggin wrote:
> > The PC unit in the processor core contains xscom registers that provide
> > low level status and control of the CPU.
> > 
> > This implements "direct controls" sufficient for OPAL (skiboot) firmware
> > use, which is to stop threads and send them non-maskable IPIs in the
> > form of SRESET interrupts.
> > 
> > POWER10 is sufficiently different (particularly QME and special wakeup)
> > from POWER9 that it is not trivial to implement by reusing the code.
> > 
> > Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> > ---
> >   include/hw/core/cpu.h     |  8 ++++
> >   include/hw/ppc/pnv.h      |  2 +
> >   include/hw/ppc/pnv_core.h |  3 ++
> >   hw/ppc/pnv.c              |  7 +++-
> >   hw/ppc/pnv_core.c         | 88 ++++++++++++++++++++++++++++++++++++---
> >   system/cpus.c             | 10 +++++
> >   6 files changed, 112 insertions(+), 6 deletions(-)
> > 
> > diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
> > index bb398e8237..52a8fc65cb 100644
> > --- a/include/hw/core/cpu.h
> > +++ b/include/hw/core/cpu.h
> > @@ -974,6 +974,14 @@ void cpu_reset_interrupt(CPUState *cpu, int mask);
> >    */
> >   void cpu_exit(CPUState *cpu);
> >   
> > +/**
> > + * cpu_pause:
> > + * @cpu: The CPU to pause.
> > + *
> > + * Resumes CPU, i.e. puts CPU into stopped state.
> > + */
> > +void cpu_pause(CPUState *cpu);
> > +
> >   /**
> >    * cpu_resume:
> >    * @cpu: The CPU to resume.
> > diff --git a/include/hw/ppc/pnv.h b/include/hw/ppc/pnv.h
> > index 93ecb062b4..bec603f1a8 100644
> > --- a/include/hw/ppc/pnv.h
> > +++ b/include/hw/ppc/pnv.h
> > @@ -111,6 +111,8 @@ PnvChip *pnv_chip_add_phb(PnvChip *chip, PnvPHB *phb);
> >   #define PNV_FDT_ADDR          0x01000000
> >   #define PNV_TIMEBASE_FREQ     512000000ULL
> >   
> > +void pnv_cpu_do_nmi(CPUState *cs);
> > +
> >   /*
> >    * BMC helpers
> >    */
> > diff --git a/include/hw/ppc/pnv_core.h b/include/hw/ppc/pnv_core.h
> > index 39f8f33e6c..9599da15ea 100644
> > --- a/include/hw/ppc/pnv_core.h
> > +++ b/include/hw/ppc/pnv_core.h
> > @@ -109,6 +109,9 @@ OBJECT_DECLARE_TYPE(PnvQuad, PnvQuadClass, PNV_QUAD)
> >   struct PnvQuad {
> >       DeviceState parent_obj;
> >   
> > +    bool special_wakeup_done;
> > +    bool special_wakeup[4];
> > +
> >       uint32_t quad_id;
> >       MemoryRegion xscom_regs;
> >       MemoryRegion xscom_qme_regs;
> > diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
> > index 5364c55bbb..765142965f 100644
> > --- a/hw/ppc/pnv.c
> > +++ b/hw/ppc/pnv.c
> > @@ -2700,12 +2700,17 @@ static void pnv_cpu_do_nmi_on_cpu(CPUState *cs, run_on_cpu_data arg)
> >       }
> >   }
> >   
> > +void pnv_cpu_do_nmi(CPUState *cs)
> > +{
> > +    async_run_on_cpu(cs, pnv_cpu_do_nmi_on_cpu, RUN_ON_CPU_NULL);
> > +}
> > +
> >   static void pnv_nmi(NMIState *n, int cpu_index, Error **errp)
> >   {
> >       CPUState *cs;
> >   
> >       CPU_FOREACH(cs) {
> > -        async_run_on_cpu(cs, pnv_cpu_do_nmi_on_cpu, RUN_ON_CPU_NULL);
> > +        pnv_cpu_do_nmi(cs);
> >       }
> >   }
>
> What about ?
>
> https://lore.kernel.org/qemu-devel/20240424093048.180966-1-clg@redhat.com/

I haven't forgotten it. I just didn't put it in the first PR since
there was quite a lot of pnv patches to do so I thought I will collect
most of them for another PR.

Thanks,
Nick
diff mbox series

Patch

diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
index bb398e8237..52a8fc65cb 100644
--- a/include/hw/core/cpu.h
+++ b/include/hw/core/cpu.h
@@ -974,6 +974,14 @@  void cpu_reset_interrupt(CPUState *cpu, int mask);
  */
 void cpu_exit(CPUState *cpu);
 
+/**
+ * cpu_pause:
+ * @cpu: The CPU to pause.
+ *
+ * Resumes CPU, i.e. puts CPU into stopped state.
+ */
+void cpu_pause(CPUState *cpu);
+
 /**
  * cpu_resume:
  * @cpu: The CPU to resume.
diff --git a/include/hw/ppc/pnv.h b/include/hw/ppc/pnv.h
index 93ecb062b4..bec603f1a8 100644
--- a/include/hw/ppc/pnv.h
+++ b/include/hw/ppc/pnv.h
@@ -111,6 +111,8 @@  PnvChip *pnv_chip_add_phb(PnvChip *chip, PnvPHB *phb);
 #define PNV_FDT_ADDR          0x01000000
 #define PNV_TIMEBASE_FREQ     512000000ULL
 
+void pnv_cpu_do_nmi(CPUState *cs);
+
 /*
  * BMC helpers
  */
diff --git a/include/hw/ppc/pnv_core.h b/include/hw/ppc/pnv_core.h
index 39f8f33e6c..9599da15ea 100644
--- a/include/hw/ppc/pnv_core.h
+++ b/include/hw/ppc/pnv_core.h
@@ -109,6 +109,9 @@  OBJECT_DECLARE_TYPE(PnvQuad, PnvQuadClass, PNV_QUAD)
 struct PnvQuad {
     DeviceState parent_obj;
 
+    bool special_wakeup_done;
+    bool special_wakeup[4];
+
     uint32_t quad_id;
     MemoryRegion xscom_regs;
     MemoryRegion xscom_qme_regs;
diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
index 5364c55bbb..765142965f 100644
--- a/hw/ppc/pnv.c
+++ b/hw/ppc/pnv.c
@@ -2700,12 +2700,17 @@  static void pnv_cpu_do_nmi_on_cpu(CPUState *cs, run_on_cpu_data arg)
     }
 }
 
+void pnv_cpu_do_nmi(CPUState *cs)
+{
+    async_run_on_cpu(cs, pnv_cpu_do_nmi_on_cpu, RUN_ON_CPU_NULL);
+}
+
 static void pnv_nmi(NMIState *n, int cpu_index, Error **errp)
 {
     CPUState *cs;
 
     CPU_FOREACH(cs) {
-        async_run_on_cpu(cs, pnv_cpu_do_nmi_on_cpu, RUN_ON_CPU_NULL);
+        pnv_cpu_do_nmi(cs);
     }
 }
 
diff --git a/hw/ppc/pnv_core.c b/hw/ppc/pnv_core.c
index 10417d92ae..835c35d90b 100644
--- a/hw/ppc/pnv_core.c
+++ b/hw/ppc/pnv_core.c
@@ -184,16 +184,40 @@  static const MemoryRegionOps pnv_core_power9_xscom_ops = {
  */
 
 #define PNV10_XSCOM_EC_CORE_THREAD_STATE    0x412
+#define PNV10_XSCOM_EC_CORE_THREAD_INFO     0x413
+#define PNV10_XSCOM_EC_CORE_DIRECT_CONTROLS 0x449
+#define PNV10_XSCOM_EC_CORE_RAS_STATUS      0x454
 
 static uint64_t pnv_core_power10_xscom_read(void *opaque, hwaddr addr,
                                            unsigned int width)
 {
+    PnvCore *pc = PNV_CORE(opaque);
+    int nr_threads = CPU_CORE(pc)->nr_threads;
+    int i;
     uint32_t offset = addr >> 3;
     uint64_t val = 0;
 
     switch (offset) {
     case PNV10_XSCOM_EC_CORE_THREAD_STATE:
-        val = 0;
+        for (i = 0; i < nr_threads; i++) {
+            PowerPCCPU *cpu = pc->threads[i];
+            CPUState *cs = CPU(cpu);
+
+            if (cs->halted) {
+                val |= PPC_BIT(56 + i);
+            }
+        }
+        break;
+    case PNV10_XSCOM_EC_CORE_THREAD_INFO:
+        break;
+    case PNV10_XSCOM_EC_CORE_RAS_STATUS:
+        for (i = 0; i < nr_threads; i++) {
+            PowerPCCPU *cpu = pc->threads[i];
+            CPUState *cs = CPU(cpu);
+            if (cs->stopped) {
+                val |= PPC_BIT(0 + 8*i) | PPC_BIT(1 + 8*i);
+            }
+        }
         break;
     default:
         qemu_log_mask(LOG_UNIMP, "%s: unimp read 0x%08x\n", __func__,
@@ -206,9 +230,45 @@  static uint64_t pnv_core_power10_xscom_read(void *opaque, hwaddr addr,
 static void pnv_core_power10_xscom_write(void *opaque, hwaddr addr,
                                          uint64_t val, unsigned int width)
 {
+    PnvCore *pc = PNV_CORE(opaque);
+    int nr_threads = CPU_CORE(pc)->nr_threads;
+    int i;
     uint32_t offset = addr >> 3;
 
     switch (offset) {
+    case PNV10_XSCOM_EC_CORE_DIRECT_CONTROLS:
+        for (i = 0; i < nr_threads; i++) {
+            PowerPCCPU *cpu = pc->threads[i];
+            CPUState *cs = CPU(cpu);
+
+            if (val & PPC_BIT(7 + 8*i)) { /* stop */
+                val &= ~PPC_BIT(7 + 8*i);
+                cpu_pause(cs);
+            }
+            if (val & PPC_BIT(6 + 8*i)) { /* start */
+                val &= ~PPC_BIT(6 + 8*i);
+                cpu_resume(cs);
+            }
+            if (val & PPC_BIT(4 + 8*i)) { /* sreset */
+                val &= ~PPC_BIT(4 + 8*i);
+                pnv_cpu_do_nmi(cs);
+            }
+            if (val & PPC_BIT(3 + 8*i)) { /* clear maint */
+                /*
+                 * Hardware has very particular cases for where clear maint
+                 * must be used and where start must be used to resume a
+                 * thread. These are not modelled exactly, just treat
+                 * this and start the same.
+                 */
+                val &= ~PPC_BIT(3 + 8*i);
+                cpu_resume(cs);
+            }
+        }
+        if (val) {
+            qemu_log_mask(LOG_UNIMP, "%s: unimp bits in DIRECT_CONTROLS 0x%016lx\n", __func__, val);
+        }
+        break;
+
     default:
         qemu_log_mask(LOG_UNIMP, "%s: unimp write 0x%08x\n", __func__,
                       offset);
@@ -525,6 +585,7 @@  static const MemoryRegionOps pnv_quad_power10_xscom_ops = {
 static uint64_t pnv_qme_power10_xscom_read(void *opaque, hwaddr addr,
                                             unsigned int width)
 {
+    PnvQuad *eq = PNV_QUAD(opaque);
     uint32_t offset = addr >> 3;
     uint64_t val = -1;
 
@@ -532,10 +593,14 @@  static uint64_t pnv_qme_power10_xscom_read(void *opaque, hwaddr addr,
      * Forth nibble selects the core within a quad, mask it to process read
      * for any core.
      */
-    switch (offset & ~0xf000) {
-    case P10_QME_SPWU_HYP:
+    switch (offset & ~PPC_BITMASK32(16, 19)) {
     case P10_QME_SSH_HYP:
-        return 0;
+        val = 0;
+        if (eq->special_wakeup_done) {
+            val |= PPC_BIT(1); /* SPWU DONE */
+            val |= PPC_BIT(4); /* SSH SPWU DONE */
+        }
+        break;
     default:
         qemu_log_mask(LOG_UNIMP, "%s: unimp read 0x%08x\n", __func__,
                       offset);
@@ -547,9 +612,22 @@  static uint64_t pnv_qme_power10_xscom_read(void *opaque, hwaddr addr,
 static void pnv_qme_power10_xscom_write(void *opaque, hwaddr addr,
                                          uint64_t val, unsigned int width)
 {
+    PnvQuad *eq = PNV_QUAD(opaque);
     uint32_t offset = addr >> 3;
+    bool set;
+    int i;
 
-    switch (offset) {
+    switch (offset & ~PPC_BITMASK32(16, 19)) {
+    case P10_QME_SPWU_HYP:
+        set = !!(val & PPC_BIT(0));
+        eq->special_wakeup_done = set;
+        for (i = 0; i < 4; i++) {
+            /* These bits select cores in the quad */
+            if (offset & PPC_BIT32(16 + i)) {
+                eq->special_wakeup[i] = set;
+            }
+        }
+        break;
     default:
         qemu_log_mask(LOG_UNIMP, "%s: unimp write 0x%08x\n", __func__,
                       offset);
diff --git a/system/cpus.c b/system/cpus.c
index 68d161d96b..1ca18ae7ea 100644
--- a/system/cpus.c
+++ b/system/cpus.c
@@ -602,6 +602,16 @@  void pause_all_vcpus(void)
     bql_lock();
 }
 
+void cpu_pause(CPUState *cpu)
+{
+    if (qemu_cpu_is_self(cpu)) {
+        qemu_cpu_stop(cpu, true);
+    } else {
+        cpu->stop = true;
+        qemu_cpu_kick(cpu);
+    }
+}
+
 void cpu_resume(CPUState *cpu)
 {
     cpu->stop = false;