From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59706) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZwKFF-0000bw-NM for qemu-devel@nongnu.org; Tue, 10 Nov 2015 20:30:42 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZwKFB-0005GY-QA for qemu-devel@nongnu.org; Tue, 10 Nov 2015 20:30:41 -0500 From: Benjamin Herrenschmidt Date: Wed, 11 Nov 2015 11:27:29 +1100 Message-Id: <1447201710-10229-17-git-send-email-benh@kernel.crashing.org> In-Reply-To: <1447201710-10229-1-git-send-email-benh@kernel.crashing.org> References: <1447201710-10229-1-git-send-email-benh@kernel.crashing.org> Subject: [Qemu-devel] [PATCH 16/77] ppc: Get out of emulation on SMT "OR" ops List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-ppc@nongnu.org Cc: qemu-devel@nongnu.org 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 --- 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