[PATCH v5 7/7] spapr/xive: Set the OS CAM line at reset

["Cédric Le Goater" <clg@kaod.org>]

When a Virtual Processor is scheduled to run on a HW thread, the
hypervisor pushes its identifier in the OS CAM line. When running with
kernel_irqchip=off, QEMU needs to emulate the same behavior.

Set the OS CAM line when the interrupt presenter of the sPAPR core is
reset. This will also cover the case of hot-plugged CPUs.

This change also has the benefit to remove the use of CPU_FOREACH()
which can be unsafe.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
---
 include/hw/ppc/spapr_xive.h |  1 -
 hw/intc/spapr_xive.c        | 48 +++++++++++++------------------------
 2 files changed, 17 insertions(+), 32 deletions(-)

diff --git a/include/hw/ppc/spapr_xive.h b/include/hw/ppc/spapr_xive.h
index d84bd5c229f0..742b7e834f2a 100644
--- a/include/hw/ppc/spapr_xive.h
+++ b/include/hw/ppc/spapr_xive.h
@@ -57,7 +57,6 @@ typedef struct SpaprXive {
 void spapr_xive_pic_print_info(SpaprXive *xive, Monitor *mon);
 
 void spapr_xive_hcall_init(SpaprMachineState *spapr);
-void spapr_xive_set_tctx_os_cam(XiveTCTX *tctx);
 void spapr_xive_mmio_set_enabled(SpaprXive *xive, bool enable);
 void spapr_xive_map_mmio(SpaprXive *xive);
 
diff --git a/hw/intc/spapr_xive.c b/hw/intc/spapr_xive.c
index 20a8d8285f64..d8e1291905c3 100644
--- a/hw/intc/spapr_xive.c
+++ b/hw/intc/spapr_xive.c
@@ -205,23 +205,6 @@ void spapr_xive_mmio_set_enabled(SpaprXive *xive, bool enable)
     memory_region_set_enabled(&xive->end_source.esb_mmio, false);
 }
 
-/*
- * When a Virtual Processor is scheduled to run on a HW thread, the
- * hypervisor pushes its identifier in the OS CAM line. Emulate the
- * same behavior under QEMU.
- */
-void spapr_xive_set_tctx_os_cam(XiveTCTX *tctx)
-{
-    uint8_t  nvt_blk;
-    uint32_t nvt_idx;
-    uint32_t nvt_cam;
-
-    spapr_xive_cpu_to_nvt(POWERPC_CPU(tctx->cs), &nvt_blk, &nvt_idx);
-
-    nvt_cam = cpu_to_be32(TM_QW1W2_VO | xive_nvt_cam_line(nvt_blk, nvt_idx));
-    memcpy(&tctx->regs[TM_QW1_OS + TM_WORD2], &nvt_cam, 4);
-}
-
 static void spapr_xive_end_reset(XiveEND *end)
 {
     memset(end, 0, sizeof(*end));
@@ -544,21 +527,32 @@ static int spapr_xive_cpu_intc_create(SpaprInterruptController *intc,
     }
 
     spapr_cpu->tctx = XIVE_TCTX(obj);
-
-    /*
-     * (TCG) Early setting the OS CAM line for hotplugged CPUs as they
-     * don't beneficiate from the reset of the XIVE IRQ backend
-     */
-    spapr_xive_set_tctx_os_cam(spapr_cpu->tctx);
     return 0;
 }
 
+static void xive_tctx_set_os_cam(XiveTCTX *tctx, uint32_t os_cam)
+{
+    uint32_t qw1w2 = cpu_to_be32(TM_QW1W2_VO | os_cam);
+    memcpy(&tctx->regs[TM_QW1_OS + TM_WORD2], &qw1w2, 4);
+}
+
 static void spapr_xive_cpu_intc_reset(SpaprInterruptController *intc,
                                      PowerPCCPU *cpu)
 {
     XiveTCTX *tctx = spapr_cpu_state(cpu)->tctx;
+    uint8_t  nvt_blk;
+    uint32_t nvt_idx;
 
     xive_tctx_reset(tctx);
+
+    /*
+     * When a Virtual Processor is scheduled to run on a HW thread,
+     * the hypervisor pushes its identifier in the OS CAM line.
+     * Emulate the same behavior under QEMU.
+     */
+    spapr_xive_cpu_to_nvt(cpu, &nvt_blk, &nvt_idx);
+
+    xive_tctx_set_os_cam(tctx, xive_nvt_cam_line(nvt_blk, nvt_idx));
 }
 
 static void spapr_xive_set_irq(SpaprInterruptController *intc, int irq, int val)
@@ -651,14 +645,6 @@ static void spapr_xive_dt(SpaprInterruptController *intc, uint32_t nr_servers,
 static int spapr_xive_activate(SpaprInterruptController *intc, Error **errp)
 {
     SpaprXive *xive = SPAPR_XIVE(intc);
-    CPUState *cs;
-
-    CPU_FOREACH(cs) {
-        PowerPCCPU *cpu = POWERPC_CPU(cs);
-
-        /* (TCG) Set the OS CAM line of the thread interrupt context. */
-        spapr_xive_set_tctx_os_cam(spapr_cpu_state(cpu)->tctx);
-    }
 
     if (kvm_enabled()) {
         int rc = spapr_irq_init_kvm(kvmppc_xive_connect, intc, errp);
-- 
2.21.0