From patchwork Fri Nov 8 02:44:16 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pingfan Liu X-Patchwork-Id: 289663 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 486DB2C00A9 for ; Fri, 8 Nov 2013 13:43:46 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755626Ab3KHCno (ORCPT ); Thu, 7 Nov 2013 21:43:44 -0500 Received: from mail-ob0-f181.google.com ([209.85.214.181]:48869 "EHLO mail-ob0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756326Ab3KHCnn (ORCPT ); Thu, 7 Nov 2013 21:43:43 -0500 Received: by mail-ob0-f181.google.com with SMTP id wp4so969781obc.26 for ; Thu, 07 Nov 2013 18:43:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id; bh=rK5qM1bZUR9c6vNRsdwAbi/kMwD07OGJzmb1J+ERd+Q=; b=U7aHKVBtwLJiQqelQI44u2LRMQed8UZ1I9AFFdCTHsZdKHUFiEte70nCwVrsqETFCx 6YZEIT2RSR5JOYQ6z7P1n4Qf53nApWpZKhwP8tKlNhNH3n2sLk1yu/hV45g4rzLcb13M 4Mf5kk+5mNHKSyChcLS8eDDX9ezt2pRhrLS6mX1GzRb0Rz2vpny5ooZTQe5LbC9JX8zJ lz1OhpnpC3bzMvD0RZPQ2+ax10UM+ma3ON36A1YBYereYVZTsRgFMTcTIfC3QuzvDReR ZJwKg7SnADL1FaAifdj4wdgvj4MYxzAIXa0yOQ5b5Q+JbIsc+WEbQ9JqKcaVJm3KXqzB 5R4w== X-Received: by 10.60.59.5 with SMTP id v5mr2740196oeq.30.1383878622729; Thu, 07 Nov 2013 18:43:42 -0800 (PST) Received: from localhost ([202.108.130.138]) by mx.google.com with ESMTPSA id xr8sm6004758obc.12.2013.11.07.18.43.40 for (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Thu, 07 Nov 2013 18:43:42 -0800 (PST) From: Liu Ping Fan To: linuxppc-dev@lists.ozlabs.org, kvm-ppc@vger.kernel.org Cc: Benjamin Herrenschmidt , Paul Mackerras , Alexander Graf Subject: [PATCH] powerpc: kvm: optimize "sc 0" as fast return Date: Fri, 8 Nov 2013 10:44:16 +0800 Message-Id: <1383878656-4196-1-git-send-email-pingfank@linux.vnet.ibm.com> X-Mailer: git-send-email 1.8.1.4 Sender: kvm-ppc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm-ppc@vger.kernel.org syscall is a very common behavior inside guest, and this patch optimizes the path for the emulation of BOOK3S_INTERRUPT_SYSCALL, so hypervisor can return to guest without heavy exit, i.e, no need to swap TLB, HTAB,.. etc Signed-off-by: Liu Ping Fan --- Compiled, but lack of bare metal, I have not tested it yet. --- arch/powerpc/kvm/book3s_hv.c | 6 ------ arch/powerpc/kvm/book3s_hv_rmhandlers.S | 13 ++++++++++++- 2 files changed, 12 insertions(+), 7 deletions(-) diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 62a2b5a..73dc852 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -628,12 +628,6 @@ static int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu, /* hcall - punt to userspace */ int i; - if (vcpu->arch.shregs.msr & MSR_PR) { - /* sc 1 from userspace - reflect to guest syscall */ - kvmppc_book3s_queue_irqprio(vcpu, BOOK3S_INTERRUPT_SYSCALL); - r = RESUME_GUEST; - break; - } run->papr_hcall.nr = kvmppc_get_gpr(vcpu, 3); for (i = 0; i < 9; ++i) run->papr_hcall.args[i] = kvmppc_get_gpr(vcpu, 4 + i); diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index c71103b..9f626c3 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -1388,7 +1388,8 @@ kvmppc_hisi: hcall_try_real_mode: ld r3,VCPU_GPR(R3)(r9) andi. r0,r11,MSR_PR - bne guest_exit_cont + /* sc 1 from userspace - reflect to guest syscall */ + bne sc_0_fast_return clrrdi r3,r3,2 cmpldi r3,hcall_real_table_end - hcall_real_table bge guest_exit_cont @@ -1409,6 +1410,16 @@ hcall_try_real_mode: ld r11,VCPU_MSR(r4) b fast_guest_return +sc_0_fast_return: + ld r10,VCPU_PC(r9) + ld r11,VCPU_MSR(r9) + mtspr SPRN_SRR0,r10 + mtspr SPRN_SRR1,r11 + li r10, BOOK3S_INTERRUPT_SYSCALL + LOAD_REG_IMMEDIATE(r3,0xffffffff87a0ffff) /* zero 33:36,42:47 */ + and r11,r11,r3 + b fast_guest_return + /* We've attempted a real mode hcall, but it's punted it back * to userspace. We need to restore some clobbered volatiles * before resuming the pass-it-to-qemu path */