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KVM: PPC: Make SLB switching code the new segment framework
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We just introduced generic segment switching code that only needs to call
small macros to do the actual switching, but keeps most of the entry / exit
code generic.

So let's move the SLB switching code over to use this new mechanism.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Alexander Graf authored and Avi Kivity committed May 17, 2010
1 parent b79fcdf commit 53e5b8b
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Showing 2 changed files with 25 additions and 160 deletions.
183 changes: 24 additions & 159 deletions arch/powerpc/kvm/book3s_64_slb.S
View file
Original file line number Diff line number Diff line change
Expand Up @@ -44,29 +44,22 @@ slb_exit_skip_ ## num:
* *
*****************************************************************************/

.global kvmppc_handler_trampoline_enter
kvmppc_handler_trampoline_enter:
.macro LOAD_GUEST_SEGMENTS

/* Required state:
*
* MSR = ~IR|DR
* R13 = PACA
* R1 = host R1
* R2 = host R2
* R9 = guest IP
* R10 = guest MSR
* all other GPRS = free
* PACA[KVM_CR] = guest CR
* PACA[KVM_XER] = guest XER
* R3 = shadow vcpu
* all other volatile GPRS = free
* SVCPU[CR] = guest CR
* SVCPU[XER] = guest XER
* SVCPU[CTR] = guest CTR
* SVCPU[LR] = guest LR
*/

mtsrr0 r9
mtsrr1 r10

/* Activate guest mode, so faults get handled by KVM */
li r11, KVM_GUEST_MODE_GUEST
stb r11, PACA_KVM_IN_GUEST(r13)

/* Remove LPAR shadow entries */

#if SLB_NUM_BOLTED == 3
Expand Down Expand Up @@ -101,14 +94,14 @@ kvmppc_handler_trampoline_enter:

/* Fill SLB with our shadow */

lbz r12, PACA_KVM_SLB_MAX(r13)
lbz r12, SVCPU_SLB_MAX(r3)
mulli r12, r12, 16
addi r12, r12, PACA_KVM_SLB
add r12, r12, r13
addi r12, r12, SVCPU_SLB
add r12, r12, r3

/* for (r11 = kvm_slb; r11 < kvm_slb + kvm_slb_size; r11+=slb_entry) */
li r11, PACA_KVM_SLB
add r11, r11, r13
li r11, SVCPU_SLB
add r11, r11, r3

slb_loop_enter:

Expand All @@ -127,134 +120,30 @@ slb_loop_enter_skip:

slb_do_enter:

/* Enter guest */

ld r0, (PACA_KVM_R0)(r13)
ld r1, (PACA_KVM_R1)(r13)
ld r2, (PACA_KVM_R2)(r13)
ld r3, (PACA_KVM_R3)(r13)
ld r4, (PACA_KVM_R4)(r13)
ld r5, (PACA_KVM_R5)(r13)
ld r6, (PACA_KVM_R6)(r13)
ld r7, (PACA_KVM_R7)(r13)
ld r8, (PACA_KVM_R8)(r13)
ld r9, (PACA_KVM_R9)(r13)
ld r10, (PACA_KVM_R10)(r13)
ld r12, (PACA_KVM_R12)(r13)

lwz r11, (PACA_KVM_CR)(r13)
mtcr r11

lwz r11, (PACA_KVM_XER)(r13)
mtxer r11

ld r11, (PACA_KVM_R11)(r13)
ld r13, (PACA_KVM_R13)(r13)

RFI
kvmppc_handler_trampoline_enter_end:


.endm

/******************************************************************************
* *
* Exit code *
* *
*****************************************************************************/

.global kvmppc_handler_trampoline_exit
kvmppc_handler_trampoline_exit:
.macro LOAD_HOST_SEGMENTS

/* Register usage at this point:
*
* SPRG_SCRATCH0 = guest R13
* R12 = exit handler id
* R13 = PACA
* PACA.KVM.SCRATCH0 = guest R12
* PACA.KVM.SCRATCH1 = guest CR
* 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
*
*/

/* Save registers */

std r0, PACA_KVM_R0(r13)
std r1, PACA_KVM_R1(r13)
std r2, PACA_KVM_R2(r13)
std r3, PACA_KVM_R3(r13)
std r4, PACA_KVM_R4(r13)
std r5, PACA_KVM_R5(r13)
std r6, PACA_KVM_R6(r13)
std r7, PACA_KVM_R7(r13)
std r8, PACA_KVM_R8(r13)
std r9, PACA_KVM_R9(r13)
std r10, PACA_KVM_R10(r13)
std r11, PACA_KVM_R11(r13)

/* Restore R1/R2 so we can handle faults */
ld r1, PACA_KVM_HOST_R1(r13)
ld r2, PACA_KVM_HOST_R2(r13)

/* Save guest PC and MSR in GPRs */
mfsrr0 r3
mfsrr1 r4

/* Get scratch'ed off registers */
mfspr r9, SPRN_SPRG_SCRATCH0
std r9, PACA_KVM_R13(r13)

ld r8, PACA_KVM_SCRATCH0(r13)
std r8, PACA_KVM_R12(r13)

lwz r7, PACA_KVM_SCRATCH1(r13)
stw r7, PACA_KVM_CR(r13)

/* Save more register state */

mfxer r6
stw r6, PACA_KVM_XER(r13)

mfdar r5
mfdsisr r6

/*
* In order for us to easily get the last instruction,
* we got the #vmexit at, we exploit the fact that the
* virtual layout is still the same here, so we can just
* ld from the guest's PC address
*/

/* We only load the last instruction when it's safe */
cmpwi r12, BOOK3S_INTERRUPT_DATA_STORAGE
beq ld_last_inst
cmpwi r12, BOOK3S_INTERRUPT_PROGRAM
beq ld_last_inst

b no_ld_last_inst

ld_last_inst:
/* Save off the guest instruction we're at */

/* Set guest mode to 'jump over instruction' so if lwz faults
* we'll just continue at the next IP. */
li r9, KVM_GUEST_MODE_SKIP
stb r9, PACA_KVM_IN_GUEST(r13)

/* 1) enable paging for data */
mfmsr r9
ori r11, r9, MSR_DR /* Enable paging for data */
mtmsr r11
/* 2) fetch the instruction */
li r0, KVM_INST_FETCH_FAILED /* In case lwz faults */
lwz r0, 0(r3)
/* 3) disable paging again */
mtmsr r9

no_ld_last_inst:

/* Unset guest mode */
li r9, KVM_GUEST_MODE_NONE
stb r9, PACA_KVM_IN_GUEST(r13)

/* Restore bolted entries from the shadow and fix it along the way */

/* We don't store anything in entry 0, so we don't need to take care of it */
Expand All @@ -275,28 +164,4 @@ no_ld_last_inst:

slb_do_exit:

/* Register usage at this point:
*
* R0 = guest last inst
* R1 = host R1
* R2 = host R2
* R3 = guest PC
* R4 = guest MSR
* R5 = guest DAR
* R6 = guest DSISR
* R12 = exit handler id
* R13 = PACA
* PACA.KVM.* = guest *
*
*/

/* RFI into the highmem handler */
mfmsr r7
ori r7, r7, MSR_IR|MSR_DR|MSR_RI /* Enable paging */
mtsrr1 r7
ld r8, PACA_KVM_VMHANDLER(r13) /* Highmem handler address */
mtsrr0 r8

RFI
kvmppc_handler_trampoline_exit_end:

.endm
2 changes: 1 addition & 1 deletion arch/powerpc/kvm/book3s_rmhandlers.S
View file
Original file line number Diff line number Diff line change
Expand Up @@ -248,4 +248,4 @@ kvmppc_trampoline_lowmem:
kvmppc_trampoline_enter:
.long kvmppc_handler_trampoline_enter - _stext

#include "book3s_64_slb.S"
#include "book3s_segment.S"

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