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[Qemu-ppc] [PATCH 16/77] ppc: Get out of emulation on SMT "OR" ops
From: |
Benjamin Herrenschmidt |
Subject: |
[Qemu-ppc] [PATCH 16/77] ppc: Get out of emulation on SMT "OR" ops |
Date: |
Wed, 11 Nov 2015 11:27:29 +1100 |
Otherwise tight loops at smt_low for example, which OPAL does,
eat so much CPU that we can't boot a kernel anymore. With that,
I can boot 8 CPUs just fine with powernv.
Signed-off-by: Benjamin Herrenschmidt <address@hidden>
---
target-ppc/translate.c | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
diff --git a/target-ppc/translate.c b/target-ppc/translate.c
index 3974cd2..e8bbd59 100644
--- a/target-ppc/translate.c
+++ b/target-ppc/translate.c
@@ -1396,6 +1396,19 @@ GEN_LOGICAL2(nand, tcg_gen_nand_tl, 0x0E, PPC_INTEGER);
/* nor & nor. */
GEN_LOGICAL2(nor, tcg_gen_nor_tl, 0x03, PPC_INTEGER);
+#if defined(TARGET_PPC64)
+static void gen_pause(DisasContext *ctx)
+{
+ TCGv_i32 t0 = tcg_const_i32(0);
+ tcg_gen_st_i32(t0, cpu_env,
+ -offsetof(PowerPCCPU, env) + offsetof(CPUState, halted));
+ tcg_temp_free_i32(t0);
+
+ /* Stop translation, this gives other CPUs a chance to run */
+ gen_exception_err(ctx, EXCP_HLT, 1);
+}
+#endif /* defined(TARGET_PPC64) */
+
/* or & or. */
static void gen_or(DisasContext *ctx)
{
@@ -1468,6 +1481,10 @@ static void gen_or(DisasContext *ctx)
tcg_gen_ori_tl(t0, t0, ((uint64_t)prio) << 50);
gen_store_spr(SPR_PPR, t0);
tcg_temp_free(t0);
+ /* Pause us out of TCG otherwise spin loops with smt_low
+ * eat too much CPU and the kernel hangs
+ */
+ gen_pause(ctx);
}
#endif
}
@@ -1493,8 +1510,6 @@ static void gen_ori(DisasContext *ctx)
target_ulong uimm = UIMM(ctx->opcode);
if (rS(ctx->opcode) == rA(ctx->opcode) && uimm == 0) {
- /* NOP */
- /* XXX: should handle special NOPs for POWER series */
return;
}
tcg_gen_ori_tl(cpu_gpr[rA(ctx->opcode)], cpu_gpr[rS(ctx->opcode)], uimm);
--
2.5.0
- [Qemu-ppc] [PATCH 15/77] ppc: Fix sign extension issue in mtmsr(d) emulation, (continued)
- [Qemu-ppc] [PATCH 15/77] ppc: Fix sign extension issue in mtmsr(d) emulation, Benjamin Herrenschmidt, 2015/11/10
- [Qemu-ppc] [PATCH 22/77] ppc: Add real mode CI load/store instructions for P7 and P8, Benjamin Herrenschmidt, 2015/11/10
- [Qemu-ppc] [PATCH 37/77] ppc/xics: Split ICS into base class and "simple" implementation, Benjamin Herrenschmidt, 2015/11/10
- [Qemu-ppc] [PATCH 24/77] ppc: Move exception generation code out of line, Benjamin Herrenschmidt, 2015/11/10
- [Qemu-ppc] [PATCH 16/77] ppc: Get out of emulation on SMT "OR" ops,
Benjamin Herrenschmidt <=
- [Qemu-ppc] [PATCH 48/77] ppc/pnv: Add model for Power8 PHB3 PCIe Host bridge, Benjamin Herrenschmidt, 2015/11/10