From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758130AbcFHQ6D (ORCPT ); Wed, 8 Jun 2016 12:58:03 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:53770 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753404AbcFHQzE (ORCPT ); Wed, 8 Jun 2016 12:55:04 -0400 X-IBM-Helo: d03dlp02.boulder.ibm.com X-IBM-MailFrom: shreyas@linux.vnet.ibm.com X-IBM-RcptTo: mpe@ellerman.id.au;linuxppc-dev@lists.ozlabs.org;mikey@neuling.org;paulus@ozlabs.org;linux-kernel@vger.kernel.org From: "Shreyas B. Prabhu" To: mpe@ellerman.id.au Cc: benh@au1.ibm.com, paulus@ozlabs.org, mikey@neuling.org, ego@linux.vnet.ibm.com, maddy@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, "Shreyas B. Prabhu" Subject: [PATCH v6 02/11] powerpc/kvm: make hypervisor state restore a function Date: Wed, 8 Jun 2016 11:54:22 -0500 X-Mailer: git-send-email 2.1.4 In-Reply-To: <1465404871-5406-1-git-send-email-shreyas@linux.vnet.ibm.com> References: <1465404871-5406-1-git-send-email-shreyas@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16060816-0004-0000-0000-00000FA0C62C X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16060816-0005-0000-0000-000075F81A90 Message-Id: <1465404871-5406-3-git-send-email-shreyas@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-06-08_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1606080190 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In the current code, when the thread wakes up in reset vector, some of the state restore code and check for whether a thread needs to branch to kvm is duplicated. Reorder the code such that this duplication is avoided. At a higher level this is what the change looks like- Before this patch - power7_wakeup_tb_loss: restore hypervisor state if (thread needed by kvm) goto kvm_start_guest restore nvgprs, cr, pc rfid to process context power7_wakeup_loss: restore nvgprs, cr, pc rfid to process context reset vector: if (waking from deep idle states) goto power7_wakeup_tb_loss else if (thread needed by kvm) goto kvm_start_guest goto power7_wakeup_loss After this patch - power7_wakeup_tb_loss: restore hypervisor state return power7_restore_hyp_resource(): if (waking from deep idle states) goto power7_wakeup_tb_loss return power7_wakeup_loss: restore nvgprs, cr, pc rfid to process context reset vector: power7_restore_hyp_resource() if (thread needed by kvm) goto kvm_start_guest goto power7_wakeup_loss Reviewed-by: Paul Mackerras Reviewed-by: Gautham R. Shenoy Signed-off-by: Shreyas B. Prabhu --- - No changes since v3 Changes in v3: ============= - Retaining GET_PACA(r13) in System Reset vector instead of moving it to power7_restore_hyp_resource - Added comments indicating entry conditions for power7_restore_hyp_resource - Improved comments around return statements arch/powerpc/kernel/exceptions-64s.S | 28 ++------------ arch/powerpc/kernel/idle_power7.S | 72 +++++++++++++++++++++--------------- 2 files changed, 46 insertions(+), 54 deletions(-) diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 4c94406..4a74d6a 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -107,25 +107,9 @@ BEGIN_FTR_SECTION beq 9f cmpwi cr3,r13,2 - - /* - * Check if last bit of HSPGR0 is set. This indicates whether we are - * waking up from winkle. - */ GET_PACA(r13) - clrldi r5,r13,63 - clrrdi r13,r13,1 - cmpwi cr4,r5,1 - mtspr SPRN_HSPRG0,r13 + bl power7_restore_hyp_resource - lbz r0,PACA_THREAD_IDLE_STATE(r13) - cmpwi cr2,r0,PNV_THREAD_NAP - bgt cr2,8f /* Either sleep or Winkle */ - - /* Waking up from nap should not cause hypervisor state loss */ - bgt cr3,. - - /* Waking up from nap */ li r0,PNV_THREAD_RUNNING stb r0,PACA_THREAD_IDLE_STATE(r13) /* Clear thread state */ @@ -143,13 +127,9 @@ BEGIN_FTR_SECTION /* Return SRR1 from power7_nap() */ mfspr r3,SPRN_SRR1 - beq cr3,2f - b power7_wakeup_noloss -2: b power7_wakeup_loss - - /* Fast Sleep wakeup on PowerNV */ -8: GET_PACA(r13) - b power7_wakeup_tb_loss + blt cr3,2f + b power7_wakeup_loss +2: b power7_wakeup_noloss 9: END_FTR_SECTION_IFSET(CPU_FTR_HVMODE | CPU_FTR_ARCH_206) diff --git a/arch/powerpc/kernel/idle_power7.S b/arch/powerpc/kernel/idle_power7.S index 705c867..d5def06 100644 --- a/arch/powerpc/kernel/idle_power7.S +++ b/arch/powerpc/kernel/idle_power7.S @@ -276,6 +276,39 @@ ALT_FTR_SECTION_END_NESTED_IFSET(CPU_FTR_ARCH_207S, 66); \ 20: nop; +/* + * Called from reset vector. Check whether we have woken up with + * hypervisor state loss. If yes, restore hypervisor state and return + * back to reset vector. + * + * r13 - Contents of HSPRG0 + * cr3 - set to gt if waking up with partial/complete hypervisor state loss + */ +_GLOBAL(power7_restore_hyp_resource) + /* + * Check if last bit of HSPGR0 is set. This indicates whether we are + * waking up from winkle. + */ + clrldi r5,r13,63 + clrrdi r13,r13,1 + cmpwi cr4,r5,1 + mtspr SPRN_HSPRG0,r13 + + lbz r0,PACA_THREAD_IDLE_STATE(r13) + cmpwi cr2,r0,PNV_THREAD_NAP + bgt cr2,power7_wakeup_tb_loss /* Either sleep or Winkle */ + + /* + * We fall through here if PACA_THREAD_IDLE_STATE shows we are waking + * up from nap. At this stage CR3 shouldn't contains 'gt' since that + * indicates we are waking with hypervisor state loss from nap. + */ + bgt cr3,. + + blr /* Return back to System Reset vector from where + power7_restore_hyp_resource was invoked */ + + _GLOBAL(power7_wakeup_tb_loss) ld r2,PACATOC(r13); ld r1,PACAR1(r13) @@ -284,11 +317,13 @@ _GLOBAL(power7_wakeup_tb_loss) * and they are restored before switching to the process context. Hence * until they are restored, they are free to be used. * - * Save SRR1 in a NVGPR as it might be clobbered in opal_call_realmode - * (called in CHECK_HMI_INTERRUPT). SRR1 is required to determine the - * wakeup reason if we branch to kvm_start_guest. + * Save SRR1 and LR in NVGPRs as they might be clobbered in + * opal_call_realmode (called in CHECK_HMI_INTERRUPT). SRR1 is required + * to determine the wakeup reason if we branch to kvm_start_guest. LR + * is required to return back to reset vector after hypervisor state + * restore is complete. */ - + mflr r17 mfspr r16,SPRN_SRR1 BEGIN_FTR_SECTION CHECK_HMI_INTERRUPT @@ -438,33 +473,10 @@ common_exit: hypervisor_state_restored: - li r5,PNV_THREAD_RUNNING - stb r5,PACA_THREAD_IDLE_STATE(r13) - mtspr SPRN_SRR1,r16 -#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE - li r0,KVM_HWTHREAD_IN_KERNEL - stb r0,HSTATE_HWTHREAD_STATE(r13) - /* Order setting hwthread_state vs. testing hwthread_req */ - sync - lbz r0,HSTATE_HWTHREAD_REQ(r13) - cmpwi r0,0 - beq 6f - b kvm_start_guest -6: -#endif - - REST_NVGPRS(r1) - REST_GPR(2, r1) - ld r3,_CCR(r1) - ld r4,_MSR(r1) - ld r5,_NIP(r1) - addi r1,r1,INT_FRAME_SIZE - mtcr r3 - mfspr r3,SPRN_SRR1 /* Return SRR1 */ - mtspr SPRN_SRR1,r4 - mtspr SPRN_SRR0,r5 - rfid + mtlr r17 + blr /* Return back to System Reset vector from where + power7_restore_hyp_resource was invoked */ fastsleep_workaround_at_exit: li r3,1 -- 2.1.4