Re: [PATCH RESEND 07/15] ppc: spapr: Implement nested PAPR hcall - H_GUEST_SET_CAPABILITIES

[Harsh Prateek Bora]

On 9/7/23 07:39, Nicholas Piggin wrote:

On Wed Sep 6, 2023 at 2:33 PM AEST, Harsh Prateek Bora wrote:

This patch implements nested PAPR hcall H_GUEST_SET_CAPABILITIES.
This is used by L1 to set capabilities of the nested guest being
created. The capabilities being set are subset of the capabilities
returned from the previous call to H_GUEST_GET_CAPABILITIES hcall.
Currently, it only supports P9/P10 capability check through PVR.

Signed-off-by: Michael Neuling <mi...@neuling.org>
Signed-off-by: Harsh Prateek Bora <hars...@linux.ibm.com>
---
  hw/ppc/spapr.c                |  1 +
  hw/ppc/spapr_nested.c         | 46 +++++++++++++++++++++++++++++++++++
  include/hw/ppc/spapr_nested.h |  3 +++
  3 files changed, 50 insertions(+)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index cbab7a825f..7c6f6ee25d 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -3443,6 +3443,7 @@ static void spapr_instance_init(Object *obj)
          "Host serial number to advertise in guest device tree");
      /* Nested */
      spapr->nested.api = 0;
+    spapr->nested.capabilities_set = false;

I would actually think about moving spapr->nested init into
spapr_nested.c.

Agree, moved.

  }

static void spapr_machine_finalizefn(Object *obj)

diff --git a/hw/ppc/spapr_nested.c b/hw/ppc/spapr_nested.c
index 37f3a49be2..9af65f257f 100644
--- a/hw/ppc/spapr_nested.c
+++ b/hw/ppc/spapr_nested.c
@@ -399,6 +399,51 @@ static target_ulong h_guest_get_capabilities(PowerPCCPU 
*cpu,
      return H_SUCCESS;
  }

+static target_ulong h_guest_set_capabilities(PowerPCCPU *cpu,

+                                             SpaprMachineState *spapr,
+                                             target_ulong opcode,
+                                              target_ulong *args)
+{
+    CPUPPCState *env = &cpu->env;
+    target_ulong flags = args[0];
+    target_ulong capabilities = args[1];
+
+    if (flags) { /* don't handle any flags capabilities for now */
+        return H_PARAMETER;
+    }
+
+

May need to do a pass over whitespace.

Sure, done.

+    /* isn't supported */
+    if (capabilities & H_GUEST_CAPABILITIES_COPY_MEM) {
+        env->gpr[4] = 0;
+        return H_P2;
+    }
+
+    if ((env->spr[SPR_PVR] & CPU_POWERPC_POWER_SERVER_MASK) ==
+        (CPU_POWERPC_POWER9_BASE)) {
+        /* We are a P9 */
+        if (!(capabilities & H_GUEST_CAPABILITIES_P9_MODE)) {
+            env->gpr[4] = 1;
+            return H_P2;
+        }
+    }
+
+    if ((env->spr[SPR_PVR] & CPU_POWERPC_POWER_SERVER_MASK) ==
+        (CPU_POWERPC_POWER10_BASE)) {
+        /* We are a P10 */

The 2 comments above aren't helpful. Just remove them.

Sure, done.

+        if (!(capabilities & H_GUEST_CAPABILITIES_P10_MODE)) {
+            env->gpr[4] = 2;
+            return H_P2;
+        }
+    }
+
+    spapr->nested.capabilities_set = true;

Is it okay to set twice? If not, add a check. If yes, remove
capabilities_set until it's needed.

Thanks for pointing it out, adding a check as appropriate.

Thanks
Harsh

+
+    spapr->nested.pvr_base = env->spr[SPR_PVR];
+
+    return H_SUCCESS;
+}
+
  void spapr_register_nested(void)
  {
      spapr_register_hypercall(KVMPPC_H_SET_PARTITION_TABLE, h_set_ptbl);
@@ -410,6 +455,7 @@ void spapr_register_nested(void)
  void spapr_register_nested_phyp(void)
  {
      spapr_register_hypercall(H_GUEST_GET_CAPABILITIES, 
h_guest_get_capabilities);
+    spapr_register_hypercall(H_GUEST_SET_CAPABILITIES, 
h_guest_set_capabilities);
  }

#else

diff --git a/include/hw/ppc/spapr_nested.h b/include/hw/ppc/spapr_nested.h
index ce198e9f70..a7996251cb 100644
--- a/include/hw/ppc/spapr_nested.h
+++ b/include/hw/ppc/spapr_nested.h
@@ -193,6 +193,9 @@
  #define H_GUEST_CAPABILITIES_COPY_MEM 0x8000000000000000
  #define H_GUEST_CAPABILITIES_P9_MODE  0x4000000000000000
  #define H_GUEST_CAPABILITIES_P10_MODE 0x2000000000000000
+#define H_GUEST_CAP_COPY_MEM_BMAP   0
+#define H_GUEST_CAP_P9_MODE_BMAP    1
+#define H_GUEST_CAP_P10_MODE_BMAP   2

typedef struct SpaprMachineStateNestedGuest {

      unsigned long vcpus;