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![Alexander Graf](/assets/img/avatar_default.png)
On LPAR guest systems Linux enables the shadow SLB to indicate to the hypervisor a number of SLB entries that always have to be available. Today we go through this shadow SLB and disable all ESID's valid bits. However, pHyp doesn't like this approach very much and honors us with fancy machine checks. Fortunately the shadow SLB descriptor also has an entry that indicates the number of valid entries following. During the lifetime of a guest we can just swap that value to 0 and don't have to worry about the SLB restoration magic. While we're touching the code, let's also make it more readable (get rid of rldicl), allow it to deal with a dynamic number of bolted SLB entries and only do shadow SLB swizzling on LPAR systems. Signed-off-by: Alexander Graf <agraf@suse.de>
153 lines
3.6 KiB
ArmAsm
153 lines
3.6 KiB
ArmAsm
/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License, version 2, as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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* Copyright SUSE Linux Products GmbH 2009
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*
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* Authors: Alexander Graf <agraf@suse.de>
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*/
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#define SHADOW_SLB_ENTRY_LEN 0x10
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#define OFFSET_ESID(x) (SHADOW_SLB_ENTRY_LEN * x)
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#define OFFSET_VSID(x) ((SHADOW_SLB_ENTRY_LEN * x) + 8)
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/******************************************************************************
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* *
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* Entry code *
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* *
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*****************************************************************************/
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.macro LOAD_GUEST_SEGMENTS
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/* Required state:
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*
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* MSR = ~IR|DR
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* R13 = PACA
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* R1 = host R1
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* R2 = host R2
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* R3 = shadow vcpu
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* all other volatile GPRS = free except R4, R6
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* SVCPU[CR] = guest CR
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* SVCPU[XER] = guest XER
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* SVCPU[CTR] = guest CTR
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* SVCPU[LR] = guest LR
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*/
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BEGIN_FW_FTR_SECTION
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/* Declare SLB shadow as 0 entries big */
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ld r11, PACA_SLBSHADOWPTR(r13)
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li r8, 0
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stb r8, 3(r11)
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END_FW_FTR_SECTION_IFSET(FW_FEATURE_LPAR)
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/* Flush SLB */
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li r10, 0
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slbmte r10, r10
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slbia
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/* Fill SLB with our shadow */
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lbz r12, SVCPU_SLB_MAX(r3)
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mulli r12, r12, 16
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addi r12, r12, SVCPU_SLB
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add r12, r12, r3
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/* for (r11 = kvm_slb; r11 < kvm_slb + kvm_slb_size; r11+=slb_entry) */
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li r11, SVCPU_SLB
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add r11, r11, r3
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slb_loop_enter:
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ld r10, 0(r11)
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andis. r9, r10, SLB_ESID_V@h
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beq slb_loop_enter_skip
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ld r9, 8(r11)
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slbmte r9, r10
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slb_loop_enter_skip:
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addi r11, r11, 16
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cmpd cr0, r11, r12
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blt slb_loop_enter
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slb_do_enter:
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.endm
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/******************************************************************************
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* *
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* Exit code *
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* *
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*****************************************************************************/
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.macro LOAD_HOST_SEGMENTS
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/* Register usage at this point:
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*
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* R1 = host R1
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* R2 = host R2
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* R12 = exit handler id
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* R13 = shadow vcpu - SHADOW_VCPU_OFF [=PACA on PPC64]
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* SVCPU.* = guest *
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* SVCPU[CR] = guest CR
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* SVCPU[XER] = guest XER
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* SVCPU[CTR] = guest CTR
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* SVCPU[LR] = guest LR
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*
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*/
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/* Remove all SLB entries that are in use. */
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li r0, r0
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slbmte r0, r0
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slbia
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/* Restore bolted entries from the shadow */
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ld r11, PACA_SLBSHADOWPTR(r13)
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BEGIN_FW_FTR_SECTION
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/* Declare SLB shadow as SLB_NUM_BOLTED entries big */
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li r8, SLB_NUM_BOLTED
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stb r8, 3(r11)
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END_FW_FTR_SECTION_IFSET(FW_FEATURE_LPAR)
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/* Manually load all entries from shadow SLB */
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li r8, SLBSHADOW_SAVEAREA
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li r7, SLBSHADOW_SAVEAREA + 8
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.rept SLB_NUM_BOLTED
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LDX_BE r10, r11, r8
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cmpdi r10, 0
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beq 1f
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LDX_BE r9, r11, r7
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slbmte r9, r10
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1: addi r7, r7, SHADOW_SLB_ENTRY_LEN
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addi r8, r8, SHADOW_SLB_ENTRY_LEN
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.endr
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isync
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sync
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slb_do_exit:
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.endm
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