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linux-apfs/arch/powerpc/kvm/book3s_64_interrupts.S
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Alexander Graf 97c4cfbe89 KVM: PPC: Enable lightweight exits again 
The PowerPC C ABI defines that registers r14-r31 need to be preserved across
function calls. Since our exit handler is written in C, we can make use of that
and don't need to reload r14-r31 on every entry/exit cycle.

This technique is also used in the BookE code and is called "lightweight exits"
there. To follow the tradition, it's called the same in Book3S.

So far this optimization was disabled though, as the code didn't do what it was
expected to do, but failed to work.

This patch fixes and enables lightweight exits again.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-03-01 12:35:46 -03:00

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/*
* 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>
*/
#include <asm/ppc_asm.h>
#include <asm/kvm_asm.h>
#include <asm/reg.h>
#include <asm/page.h>
#include <asm/asm-offsets.h>
#include <asm/exception-64s.h>
#define KVMPPC_HANDLE_EXIT .kvmppc_handle_exit
#define ULONG_SIZE 8
#define VCPU_GPR(n) (VCPU_GPRS + (n * ULONG_SIZE))
.macro mfpaca tmp_reg, src_reg, offset, vcpu_reg
ld \tmp_reg, (PACA_EXMC+\offset)(r13)
std \tmp_reg, VCPU_GPR(\src_reg)(\vcpu_reg)
.endm
.macro DISABLE_INTERRUPTS
mfmsr r0
rldicl r0,r0,48,1
rotldi r0,r0,16
mtmsrd r0,1
.endm
#define VCPU_LOAD_NVGPRS(vcpu) \
ld r14, VCPU_GPR(r14)(vcpu); \
ld r15, VCPU_GPR(r15)(vcpu); \
ld r16, VCPU_GPR(r16)(vcpu); \
ld r17, VCPU_GPR(r17)(vcpu); \
ld r18, VCPU_GPR(r18)(vcpu); \
ld r19, VCPU_GPR(r19)(vcpu); \
ld r20, VCPU_GPR(r20)(vcpu); \
ld r21, VCPU_GPR(r21)(vcpu); \
ld r22, VCPU_GPR(r22)(vcpu); \
ld r23, VCPU_GPR(r23)(vcpu); \
ld r24, VCPU_GPR(r24)(vcpu); \
ld r25, VCPU_GPR(r25)(vcpu); \
ld r26, VCPU_GPR(r26)(vcpu); \
ld r27, VCPU_GPR(r27)(vcpu); \
ld r28, VCPU_GPR(r28)(vcpu); \
ld r29, VCPU_GPR(r29)(vcpu); \
ld r30, VCPU_GPR(r30)(vcpu); \
ld r31, VCPU_GPR(r31)(vcpu); \
/*****************************************************************************
* *
* Guest entry / exit code that is in kernel module memory (highmem) *
* *
****************************************************************************/
/* Registers:
* r3: kvm_run pointer
* r4: vcpu pointer
*/
_GLOBAL(__kvmppc_vcpu_entry)
kvm_start_entry:
/* Write correct stack frame */
mflr r0
std r0,16(r1)
/* Save host state to the stack */
stdu r1, -SWITCH_FRAME_SIZE(r1)
/* Save r3 (kvm_run) and r4 (vcpu) */
SAVE_2GPRS(3, r1)
/* Save non-volatile registers (r14 - r31) */
SAVE_NVGPRS(r1)
/* Save LR */
std r0, _LINK(r1)
/* Load non-volatile guest state from the vcpu */
VCPU_LOAD_NVGPRS(r4)
kvm_start_lightweight:
ld r9, VCPU_PC(r4) /* r9 = vcpu->arch.pc */
ld r10, VCPU_SHADOW_MSR(r4) /* r10 = vcpu->arch.shadow_msr */
DISABLE_INTERRUPTS
/* Save R1/R2 in the PACA */
std r1, PACAR1(r13)
std r2, (PACA_EXMC+EX_SRR0)(r13)
ld r3, VCPU_HIGHMEM_HANDLER(r4)
std r3, PACASAVEDMSR(r13)
ld r3, VCPU_TRAMPOLINE_ENTER(r4)
mtsrr0 r3
LOAD_REG_IMMEDIATE(r3, MSR_KERNEL & ~(MSR_IR | MSR_DR))
mtsrr1 r3
/* Load guest state in the respective registers */
lwz r3, VCPU_CR(r4) /* r3 = vcpu->arch.cr */
stw r3, (PACA_EXMC + EX_CCR)(r13)
ld r3, VCPU_CTR(r4) /* r3 = vcpu->arch.ctr */
mtctr r3 /* CTR = r3 */
ld r3, VCPU_LR(r4) /* r3 = vcpu->arch.lr */
mtlr r3 /* LR = r3 */
ld r3, VCPU_XER(r4) /* r3 = vcpu->arch.xer */
std r3, (PACA_EXMC + EX_R3)(r13)
/* Some guests may need to have dcbz set to 32 byte length.
*
* Usually we ensure that by patching the guest's instructions
* to trap on dcbz and emulate it in the hypervisor.
*
* If we can, we should tell the CPU to use 32 byte dcbz though,
* because that's a lot faster.
*/
ld r3, VCPU_HFLAGS(r4)
rldicl. r3, r3, 0, 63 /* CR = ((r3 & 1) == 0) */
beq no_dcbz32_on
mfspr r3,SPRN_HID5
ori r3, r3, 0x80 /* XXX HID5_dcbz32 = 0x80 */
mtspr SPRN_HID5,r3
no_dcbz32_on:
/* Load guest GPRs */
ld r3, VCPU_GPR(r9)(r4)
std r3, (PACA_EXMC + EX_R9)(r13)
ld r3, VCPU_GPR(r10)(r4)
std r3, (PACA_EXMC + EX_R10)(r13)
ld r3, VCPU_GPR(r11)(r4)
std r3, (PACA_EXMC + EX_R11)(r13)
ld r3, VCPU_GPR(r12)(r4)
std r3, (PACA_EXMC + EX_R12)(r13)
ld r3, VCPU_GPR(r13)(r4)
std r3, (PACA_EXMC + EX_R13)(r13)
ld r0, VCPU_GPR(r0)(r4)
ld r1, VCPU_GPR(r1)(r4)
ld r2, VCPU_GPR(r2)(r4)
ld r3, VCPU_GPR(r3)(r4)
ld r5, VCPU_GPR(r5)(r4)
ld r6, VCPU_GPR(r6)(r4)
ld r7, VCPU_GPR(r7)(r4)
ld r8, VCPU_GPR(r8)(r4)
ld r4, VCPU_GPR(r4)(r4)
/* This sets the Magic value for the trampoline */
li r11, 1
stb r11, PACA_KVM_IN_GUEST(r13)
/* Jump to SLB patching handlder and into our guest */
RFI
/*
* This is the handler in module memory. It gets jumped at from the
* lowmem trampoline code, so it's basically the guest exit code.
*
*/
.global kvmppc_handler_highmem
kvmppc_handler_highmem:
/*
* Register usage at this point:
*
* R00 = guest R13
* R01 = host R1
* R02 = host R2
* R10 = guest PC
* R11 = guest MSR
* R12 = exit handler id
* R13 = PACA
* PACA.exmc.R9 = guest R1
* PACA.exmc.R10 = guest R10
* PACA.exmc.R11 = guest R11
* PACA.exmc.R12 = guest R12
* PACA.exmc.R13 = guest R2
* PACA.exmc.DAR = guest DAR
* PACA.exmc.DSISR = guest DSISR
* PACA.exmc.LR = guest instruction
* PACA.exmc.CCR = guest CR
* PACA.exmc.SRR0 = guest R0
*
*/
std r3, (PACA_EXMC+EX_R3)(r13)
/* save the exit id in R3 */
mr r3, r12
/* R12 = vcpu */
ld r12, GPR4(r1)
/* Now save the guest state */
std r0, VCPU_GPR(r13)(r12)
std r4, VCPU_GPR(r4)(r12)
std r5, VCPU_GPR(r5)(r12)
std r6, VCPU_GPR(r6)(r12)
std r7, VCPU_GPR(r7)(r12)
std r8, VCPU_GPR(r8)(r12)
std r9, VCPU_GPR(r9)(r12)
/* get registers from PACA */
mfpaca r5, r0, EX_SRR0, r12
mfpaca r5, r3, EX_R3, r12
mfpaca r5, r1, EX_R9, r12
mfpaca r5, r10, EX_R10, r12
mfpaca r5, r11, EX_R11, r12
mfpaca r5, r12, EX_R12, r12
mfpaca r5, r2, EX_R13, r12
lwz r5, (PACA_EXMC+EX_LR)(r13)
stw r5, VCPU_LAST_INST(r12)
lwz r5, (PACA_EXMC+EX_CCR)(r13)
stw r5, VCPU_CR(r12)
ld r5, VCPU_HFLAGS(r12)
rldicl. r5, r5, 0, 63 /* CR = ((r5 & 1) == 0) */
beq no_dcbz32_off
mfspr r5,SPRN_HID5
rldimi r5,r5,6,56
mtspr SPRN_HID5,r5
no_dcbz32_off:
std r14, VCPU_GPR(r14)(r12)
std r15, VCPU_GPR(r15)(r12)
std r16, VCPU_GPR(r16)(r12)
std r17, VCPU_GPR(r17)(r12)
std r18, VCPU_GPR(r18)(r12)
std r19, VCPU_GPR(r19)(r12)
std r20, VCPU_GPR(r20)(r12)
std r21, VCPU_GPR(r21)(r12)
std r22, VCPU_GPR(r22)(r12)
std r23, VCPU_GPR(r23)(r12)
std r24, VCPU_GPR(r24)(r12)
std r25, VCPU_GPR(r25)(r12)
std r26, VCPU_GPR(r26)(r12)
std r27, VCPU_GPR(r27)(r12)
std r28, VCPU_GPR(r28)(r12)
std r29, VCPU_GPR(r29)(r12)
std r30, VCPU_GPR(r30)(r12)
std r31, VCPU_GPR(r31)(r12)
/* Save guest PC (R10) */
std r10, VCPU_PC(r12)
/* Save guest msr (R11) */
std r11, VCPU_SHADOW_MSR(r12)
/* Save guest CTR (in R12) */
mfctr r5
std r5, VCPU_CTR(r12)
/* Save guest LR */
mflr r5
std r5, VCPU_LR(r12)
/* Save guest XER */
mfxer r5
std r5, VCPU_XER(r12)
/* Save guest DAR */
ld r5, (PACA_EXMC+EX_DAR)(r13)
std r5, VCPU_FAULT_DEAR(r12)
/* Save guest DSISR */
lwz r5, (PACA_EXMC+EX_DSISR)(r13)
std r5, VCPU_FAULT_DSISR(r12)
/* Restore host msr -> SRR1 */
ld r7, VCPU_HOST_MSR(r12)
mtsrr1 r7
/* Restore host IP -> SRR0 */
ld r6, VCPU_HOST_RETIP(r12)
mtsrr0 r6
/*
* For some interrupts, we need to call the real Linux
* handler, so it can do work for us. This has to happen
* as if the interrupt arrived from the kernel though,
* so let's fake it here where most state is restored.
*
* Call Linux for hardware interrupts/decrementer
* r3 = address of interrupt handler (exit reason)
*/
cmpwi r3, BOOK3S_INTERRUPT_EXTERNAL
beq call_linux_handler
cmpwi r3, BOOK3S_INTERRUPT_DECREMENTER
beq call_linux_handler
/* Back to Interruptable Mode! (goto kvm_return_point) */
RFI
call_linux_handler:
/*
* If we land here we need to jump back to the handler we
* came from.
*
* We have a page that we can access from real mode, so let's
* jump back to that and use it as a trampoline to get back into the
* interrupt handler!
*
* R3 still contains the exit code,
* R6 VCPU_HOST_RETIP and
* R7 VCPU_HOST_MSR
*/
mtlr r3
ld r5, VCPU_TRAMPOLINE_LOWMEM(r12)
mtsrr0 r5
LOAD_REG_IMMEDIATE(r5, MSR_KERNEL & ~(MSR_IR | MSR_DR))
mtsrr1 r5
RFI
.global kvm_return_point
kvm_return_point:
/* Jump back to lightweight entry if we're supposed to */
/* go back into the guest */
/* Pass the exit number as 3rd argument to kvmppc_handle_exit */
mr r5, r3
/* Restore r3 (kvm_run) and r4 (vcpu) */
REST_2GPRS(3, r1)
bl KVMPPC_HANDLE_EXIT
/* If RESUME_GUEST, get back in the loop */
cmpwi r3, RESUME_GUEST
beq kvm_loop_lightweight
cmpwi r3, RESUME_GUEST_NV
beq kvm_loop_heavyweight
kvm_exit_loop:
ld r4, _LINK(r1)
mtlr r4
/* Restore non-volatile host registers (r14 - r31) */
REST_NVGPRS(r1)
addi r1, r1, SWITCH_FRAME_SIZE
blr
kvm_loop_heavyweight:
ld r4, _LINK(r1)
std r4, (16 + SWITCH_FRAME_SIZE)(r1)
/* Load vcpu and cpu_run */
REST_2GPRS(3, r1)
/* Load non-volatile guest state from the vcpu */
VCPU_LOAD_NVGPRS(r4)
/* Jump back into the beginning of this function */
b kvm_start_lightweight
kvm_loop_lightweight:
/* We'll need the vcpu pointer */
REST_GPR(4, r1)
/* Jump back into the beginning of this function */
b kvm_start_lightweight
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