linux/arch/powerpc/kvm/book3s_64_slb.S
Alexander Graf d8d164a985 KVM: PPC: Book3S PR: Rework SLB switching code
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>
2014-05-30 14:26:30 +02:00

154 lines
3.6 KiB
ArmAsm

/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* Copyright SUSE Linux Products GmbH 2009
*
* Authors: Alexander Graf <agraf@suse.de>
*/
#define SHADOW_SLB_ENTRY_LEN 0x10
#define OFFSET_ESID(x) (SHADOW_SLB_ENTRY_LEN * x)
#define OFFSET_VSID(x) ((SHADOW_SLB_ENTRY_LEN * x) + 8)
/******************************************************************************
* *
* Entry code *
* *
*****************************************************************************/
.macro LOAD_GUEST_SEGMENTS
/* Required state:
*
* MSR = ~IR|DR
* R13 = PACA
* R1 = host R1
* R2 = host R2
* R3 = shadow vcpu
* all other volatile GPRS = free except R4, R6
* SVCPU[CR] = guest CR
* SVCPU[XER] = guest XER
* SVCPU[CTR] = guest CTR
* SVCPU[LR] = guest LR
*/
BEGIN_FW_FTR_SECTION
/* Declare SLB shadow as 0 entries big */
ld r11, PACA_SLBSHADOWPTR(r13)
li r8, 0
stb r8, 3(r11)
END_FW_FTR_SECTION_IFSET(FW_FEATURE_LPAR)
/* Flush SLB */
li r10, 0
slbmte r10, r10
slbia
/* Fill SLB with our shadow */
lbz r12, SVCPU_SLB_MAX(r3)
mulli r12, r12, 16
addi r12, r12, SVCPU_SLB
add r12, r12, r3
/* for (r11 = kvm_slb; r11 < kvm_slb + kvm_slb_size; r11+=slb_entry) */
li r11, SVCPU_SLB
add r11, r11, r3
slb_loop_enter:
ld r10, 0(r11)
andis. r9, r10, SLB_ESID_V@h
beq slb_loop_enter_skip
ld r9, 8(r11)
slbmte r9, r10
slb_loop_enter_skip:
addi r11, r11, 16
cmpd cr0, r11, r12
blt slb_loop_enter
slb_do_enter:
.endm
/******************************************************************************
* *
* Exit code *
* *
*****************************************************************************/
.macro LOAD_HOST_SEGMENTS
/* Register usage at this point:
*
* R1 = host R1
* R2 = host R2
* R12 = exit handler id
* R13 = shadow vcpu - SHADOW_VCPU_OFF [=PACA on PPC64]
* SVCPU.* = guest *
* SVCPU[CR] = guest CR
* SVCPU[XER] = guest XER
* SVCPU[CTR] = guest CTR
* SVCPU[LR] = guest LR
*
*/
/* Remove all SLB entries that are in use. */
li r0, r0
slbmte r0, r0
slbia
/* Restore bolted entries from the shadow */
ld r11, PACA_SLBSHADOWPTR(r13)
BEGIN_FW_FTR_SECTION
/* Declare SLB shadow as SLB_NUM_BOLTED entries big */
li r8, SLB_NUM_BOLTED
stb r8, 3(r11)
END_FW_FTR_SECTION_IFSET(FW_FEATURE_LPAR)
/* Manually load all entries from shadow SLB */
li r8, SLBSHADOW_SAVEAREA
li r7, SLBSHADOW_SAVEAREA + 8
.rept SLB_NUM_BOLTED
LDX_BE r10, r11, r8
cmpdi r10, 0
beq 1f
LDX_BE r9, r11, r7
slbmte r9, r10
1: addi r7, r7, SHADOW_SLB_ENTRY_LEN
addi r8, r8, SHADOW_SLB_ENTRY_LEN
.endr
isync
sync
slb_do_exit:
.endm