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linux/arch/powerpc/kvm/booke_interrupts.S
Hollis Blanchard 73e75b416f KVM: ppc: Implement in-kernel exit timing statistics 
Existing KVM statistics are either just counters (kvm_stat) reported for
KVM generally or trace based aproaches like kvm_trace.
For KVM on powerpc we had the need to track the timings of the different exit
types. While this could be achieved parsing data created with a kvm_trace
extension this adds too much overhead (at least on embedded PowerPC) slowing
down the workloads we wanted to measure.

Therefore this patch adds a in-kernel exit timing statistic to the powerpc kvm
code. These statistic is available per vm&vcpu under the kvm debugfs directory.
As this statistic is low, but still some overhead it can be enabled via a
.config entry and should be off by default.

Since this patch touched all powerpc kvm_stat code anyway this code is now
merged and simplified together with the exit timing statistic code (still
working with exit timing disabled in .config).

Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:55:41 +02:00

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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 IBM Corp. 2007
*
* Authors: Hollis Blanchard <hollisb@us.ibm.com>
*/
#include <asm/ppc_asm.h>
#include <asm/kvm_asm.h>
#include <asm/reg.h>
#include <asm/mmu-44x.h>
#include <asm/page.h>
#include <asm/asm-offsets.h>
#define KVMPPC_MSR_MASK (MSR_CE|MSR_EE|MSR_PR|MSR_DE|MSR_ME|MSR_IS|MSR_DS)
#define VCPU_GPR(n) (VCPU_GPRS + (n * 4))
/* The host stack layout: */
#define HOST_R1 0 /* Implied by stwu. */
#define HOST_CALLEE_LR 4
#define HOST_RUN 8
/* r2 is special: it holds 'current', and it made nonvolatile in the
* kernel with the -ffixed-r2 gcc option. */
#define HOST_R2 12
#define HOST_NV_GPRS 16
#define HOST_NV_GPR(n) (HOST_NV_GPRS + ((n - 14) * 4))
#define HOST_MIN_STACK_SIZE (HOST_NV_GPR(31) + 4)
#define HOST_STACK_SIZE (((HOST_MIN_STACK_SIZE + 15) / 16) * 16) /* Align. */
#define HOST_STACK_LR (HOST_STACK_SIZE + 4) /* In caller stack frame. */
#define NEED_INST_MASK ((1<<BOOKE_INTERRUPT_PROGRAM) | \
(1<<BOOKE_INTERRUPT_DTLB_MISS) | \
(1<<BOOKE_INTERRUPT_DEBUG))
#define NEED_DEAR_MASK ((1<<BOOKE_INTERRUPT_DATA_STORAGE) | \
(1<<BOOKE_INTERRUPT_DTLB_MISS))
#define NEED_ESR_MASK ((1<<BOOKE_INTERRUPT_DATA_STORAGE) | \
(1<<BOOKE_INTERRUPT_INST_STORAGE) | \
(1<<BOOKE_INTERRUPT_PROGRAM) | \
(1<<BOOKE_INTERRUPT_DTLB_MISS))
.macro KVM_HANDLER ivor_nr
_GLOBAL(kvmppc_handler_\ivor_nr)
/* Get pointer to vcpu and record exit number. */
mtspr SPRN_SPRG0, r4
mfspr r4, SPRN_SPRG1
stw r5, VCPU_GPR(r5)(r4)
stw r6, VCPU_GPR(r6)(r4)
mfctr r5
lis r6, kvmppc_resume_host@h
stw r5, VCPU_CTR(r4)
li r5, \ivor_nr
ori r6, r6, kvmppc_resume_host@l
mtctr r6
bctr
.endm
_GLOBAL(kvmppc_handlers_start)
KVM_HANDLER BOOKE_INTERRUPT_CRITICAL
KVM_HANDLER BOOKE_INTERRUPT_MACHINE_CHECK
KVM_HANDLER BOOKE_INTERRUPT_DATA_STORAGE
KVM_HANDLER BOOKE_INTERRUPT_INST_STORAGE
KVM_HANDLER BOOKE_INTERRUPT_EXTERNAL
KVM_HANDLER BOOKE_INTERRUPT_ALIGNMENT
KVM_HANDLER BOOKE_INTERRUPT_PROGRAM
KVM_HANDLER BOOKE_INTERRUPT_FP_UNAVAIL
KVM_HANDLER BOOKE_INTERRUPT_SYSCALL
KVM_HANDLER BOOKE_INTERRUPT_AP_UNAVAIL
KVM_HANDLER BOOKE_INTERRUPT_DECREMENTER
KVM_HANDLER BOOKE_INTERRUPT_FIT
KVM_HANDLER BOOKE_INTERRUPT_WATCHDOG
KVM_HANDLER BOOKE_INTERRUPT_DTLB_MISS
KVM_HANDLER BOOKE_INTERRUPT_ITLB_MISS
KVM_HANDLER BOOKE_INTERRUPT_DEBUG
_GLOBAL(kvmppc_handler_len)
.long kvmppc_handler_1 - kvmppc_handler_0
/* Registers:
* SPRG0: guest r4
* r4: vcpu pointer
* r5: KVM exit number
*/
_GLOBAL(kvmppc_resume_host)
stw r3, VCPU_GPR(r3)(r4)
mfcr r3
stw r3, VCPU_CR(r4)
stw r7, VCPU_GPR(r7)(r4)
stw r8, VCPU_GPR(r8)(r4)
stw r9, VCPU_GPR(r9)(r4)
li r6, 1
slw r6, r6, r5
#ifdef CONFIG_KVM_EXIT_TIMING
/* save exit time */
1:
mfspr r7, SPRN_TBRU
mfspr r8, SPRN_TBRL
mfspr r9, SPRN_TBRU
cmpw r9, r7
bne 1b
stw r8, VCPU_TIMING_EXIT_TBL(r4)
stw r9, VCPU_TIMING_EXIT_TBU(r4)
#endif
/* Save the faulting instruction and all GPRs for emulation. */
andi. r7, r6, NEED_INST_MASK
beq ..skip_inst_copy
mfspr r9, SPRN_SRR0
mfmsr r8
ori r7, r8, MSR_DS
mtmsr r7
isync
lwz r9, 0(r9)
mtmsr r8
isync
stw r9, VCPU_LAST_INST(r4)
stw r15, VCPU_GPR(r15)(r4)
stw r16, VCPU_GPR(r16)(r4)
stw r17, VCPU_GPR(r17)(r4)
stw r18, VCPU_GPR(r18)(r4)
stw r19, VCPU_GPR(r19)(r4)
stw r20, VCPU_GPR(r20)(r4)
stw r21, VCPU_GPR(r21)(r4)
stw r22, VCPU_GPR(r22)(r4)
stw r23, VCPU_GPR(r23)(r4)
stw r24, VCPU_GPR(r24)(r4)
stw r25, VCPU_GPR(r25)(r4)
stw r26, VCPU_GPR(r26)(r4)
stw r27, VCPU_GPR(r27)(r4)
stw r28, VCPU_GPR(r28)(r4)
stw r29, VCPU_GPR(r29)(r4)
stw r30, VCPU_GPR(r30)(r4)
stw r31, VCPU_GPR(r31)(r4)
..skip_inst_copy:
/* Also grab DEAR and ESR before the host can clobber them. */
andi. r7, r6, NEED_DEAR_MASK
beq ..skip_dear
mfspr r9, SPRN_DEAR
stw r9, VCPU_FAULT_DEAR(r4)
..skip_dear:
andi. r7, r6, NEED_ESR_MASK
beq ..skip_esr
mfspr r9, SPRN_ESR
stw r9, VCPU_FAULT_ESR(r4)
..skip_esr:
/* Save remaining volatile guest register state to vcpu. */
stw r0, VCPU_GPR(r0)(r4)
stw r1, VCPU_GPR(r1)(r4)
stw r2, VCPU_GPR(r2)(r4)
stw r10, VCPU_GPR(r10)(r4)
stw r11, VCPU_GPR(r11)(r4)
stw r12, VCPU_GPR(r12)(r4)
stw r13, VCPU_GPR(r13)(r4)
stw r14, VCPU_GPR(r14)(r4) /* We need a NV GPR below. */
mflr r3
stw r3, VCPU_LR(r4)
mfxer r3
stw r3, VCPU_XER(r4)
mfspr r3, SPRN_SPRG0
stw r3, VCPU_GPR(r4)(r4)
mfspr r3, SPRN_SRR0
stw r3, VCPU_PC(r4)
/* Restore host stack pointer and PID before IVPR, since the host
* exception handlers use them. */
lwz r1, VCPU_HOST_STACK(r4)
lwz r3, VCPU_HOST_PID(r4)
mtspr SPRN_PID, r3
/* Restore host IVPR before re-enabling interrupts. We cheat and know
* that Linux IVPR is always 0xc0000000. */
lis r3, 0xc000
mtspr SPRN_IVPR, r3
/* Switch to kernel stack and jump to handler. */
LOAD_REG_ADDR(r3, kvmppc_handle_exit)
mtctr r3
lwz r3, HOST_RUN(r1)
lwz r2, HOST_R2(r1)
mr r14, r4 /* Save vcpu pointer. */
bctrl /* kvmppc_handle_exit() */
/* Restore vcpu pointer and the nonvolatiles we used. */
mr r4, r14
lwz r14, VCPU_GPR(r14)(r4)
/* Sometimes instruction emulation must restore complete GPR state. */
andi. r5, r3, RESUME_FLAG_NV
beq ..skip_nv_load
lwz r15, VCPU_GPR(r15)(r4)
lwz r16, VCPU_GPR(r16)(r4)
lwz r17, VCPU_GPR(r17)(r4)
lwz r18, VCPU_GPR(r18)(r4)
lwz r19, VCPU_GPR(r19)(r4)
lwz r20, VCPU_GPR(r20)(r4)
lwz r21, VCPU_GPR(r21)(r4)
lwz r22, VCPU_GPR(r22)(r4)
lwz r23, VCPU_GPR(r23)(r4)
lwz r24, VCPU_GPR(r24)(r4)
lwz r25, VCPU_GPR(r25)(r4)
lwz r26, VCPU_GPR(r26)(r4)
lwz r27, VCPU_GPR(r27)(r4)
lwz r28, VCPU_GPR(r28)(r4)
lwz r29, VCPU_GPR(r29)(r4)
lwz r30, VCPU_GPR(r30)(r4)
lwz r31, VCPU_GPR(r31)(r4)
..skip_nv_load:
/* Should we return to the guest? */
andi. r5, r3, RESUME_FLAG_HOST
beq lightweight_exit
srawi r3, r3, 2 /* Shift -ERR back down. */
heavyweight_exit:
/* Not returning to guest. */
/* We already saved guest volatile register state; now save the
* non-volatiles. */
stw r15, VCPU_GPR(r15)(r4)
stw r16, VCPU_GPR(r16)(r4)
stw r17, VCPU_GPR(r17)(r4)
stw r18, VCPU_GPR(r18)(r4)
stw r19, VCPU_GPR(r19)(r4)
stw r20, VCPU_GPR(r20)(r4)
stw r21, VCPU_GPR(r21)(r4)
stw r22, VCPU_GPR(r22)(r4)
stw r23, VCPU_GPR(r23)(r4)
stw r24, VCPU_GPR(r24)(r4)
stw r25, VCPU_GPR(r25)(r4)
stw r26, VCPU_GPR(r26)(r4)
stw r27, VCPU_GPR(r27)(r4)
stw r28, VCPU_GPR(r28)(r4)
stw r29, VCPU_GPR(r29)(r4)
stw r30, VCPU_GPR(r30)(r4)
stw r31, VCPU_GPR(r31)(r4)
/* Load host non-volatile register state from host stack. */
lwz r14, HOST_NV_GPR(r14)(r1)
lwz r15, HOST_NV_GPR(r15)(r1)
lwz r16, HOST_NV_GPR(r16)(r1)
lwz r17, HOST_NV_GPR(r17)(r1)
lwz r18, HOST_NV_GPR(r18)(r1)
lwz r19, HOST_NV_GPR(r19)(r1)
lwz r20, HOST_NV_GPR(r20)(r1)
lwz r21, HOST_NV_GPR(r21)(r1)
lwz r22, HOST_NV_GPR(r22)(r1)
lwz r23, HOST_NV_GPR(r23)(r1)
lwz r24, HOST_NV_GPR(r24)(r1)
lwz r25, HOST_NV_GPR(r25)(r1)
lwz r26, HOST_NV_GPR(r26)(r1)
lwz r27, HOST_NV_GPR(r27)(r1)
lwz r28, HOST_NV_GPR(r28)(r1)
lwz r29, HOST_NV_GPR(r29)(r1)
lwz r30, HOST_NV_GPR(r30)(r1)
lwz r31, HOST_NV_GPR(r31)(r1)
/* Return to kvm_vcpu_run(). */
lwz r4, HOST_STACK_LR(r1)
addi r1, r1, HOST_STACK_SIZE
mtlr r4
/* r3 still contains the return code from kvmppc_handle_exit(). */
blr
/* Registers:
* r3: kvm_run pointer
* r4: vcpu pointer
*/
_GLOBAL(__kvmppc_vcpu_run)
stwu r1, -HOST_STACK_SIZE(r1)
stw r1, VCPU_HOST_STACK(r4) /* Save stack pointer to vcpu. */
/* Save host state to stack. */
stw r3, HOST_RUN(r1)
mflr r3
stw r3, HOST_STACK_LR(r1)
/* Save host non-volatile register state to stack. */
stw r14, HOST_NV_GPR(r14)(r1)
stw r15, HOST_NV_GPR(r15)(r1)
stw r16, HOST_NV_GPR(r16)(r1)
stw r17, HOST_NV_GPR(r17)(r1)
stw r18, HOST_NV_GPR(r18)(r1)
stw r19, HOST_NV_GPR(r19)(r1)
stw r20, HOST_NV_GPR(r20)(r1)
stw r21, HOST_NV_GPR(r21)(r1)
stw r22, HOST_NV_GPR(r22)(r1)
stw r23, HOST_NV_GPR(r23)(r1)
stw r24, HOST_NV_GPR(r24)(r1)
stw r25, HOST_NV_GPR(r25)(r1)
stw r26, HOST_NV_GPR(r26)(r1)
stw r27, HOST_NV_GPR(r27)(r1)
stw r28, HOST_NV_GPR(r28)(r1)
stw r29, HOST_NV_GPR(r29)(r1)
stw r30, HOST_NV_GPR(r30)(r1)
stw r31, HOST_NV_GPR(r31)(r1)
/* Load guest non-volatiles. */
lwz r14, VCPU_GPR(r14)(r4)
lwz r15, VCPU_GPR(r15)(r4)
lwz r16, VCPU_GPR(r16)(r4)
lwz r17, VCPU_GPR(r17)(r4)
lwz r18, VCPU_GPR(r18)(r4)
lwz r19, VCPU_GPR(r19)(r4)
lwz r20, VCPU_GPR(r20)(r4)
lwz r21, VCPU_GPR(r21)(r4)
lwz r22, VCPU_GPR(r22)(r4)
lwz r23, VCPU_GPR(r23)(r4)
lwz r24, VCPU_GPR(r24)(r4)
lwz r25, VCPU_GPR(r25)(r4)
lwz r26, VCPU_GPR(r26)(r4)
lwz r27, VCPU_GPR(r27)(r4)
lwz r28, VCPU_GPR(r28)(r4)
lwz r29, VCPU_GPR(r29)(r4)
lwz r30, VCPU_GPR(r30)(r4)
lwz r31, VCPU_GPR(r31)(r4)
lightweight_exit:
stw r2, HOST_R2(r1)
mfspr r3, SPRN_PID
stw r3, VCPU_HOST_PID(r4)
lwz r3, VCPU_SHADOW_PID(r4)
mtspr SPRN_PID, r3
iccci 0, 0 /* XXX hack */
/* Load some guest volatiles. */
lwz r0, VCPU_GPR(r0)(r4)
lwz r2, VCPU_GPR(r2)(r4)
lwz r9, VCPU_GPR(r9)(r4)
lwz r10, VCPU_GPR(r10)(r4)
lwz r11, VCPU_GPR(r11)(r4)
lwz r12, VCPU_GPR(r12)(r4)
lwz r13, VCPU_GPR(r13)(r4)
lwz r3, VCPU_LR(r4)
mtlr r3
lwz r3, VCPU_XER(r4)
mtxer r3
/* Switch the IVPR. XXX If we take a TLB miss after this we're screwed,
* so how do we make sure vcpu won't fault? */
lis r8, kvmppc_booke_handlers@ha
lwz r8, kvmppc_booke_handlers@l(r8)
mtspr SPRN_IVPR, r8
/* Save vcpu pointer for the exception handlers. */
mtspr SPRN_SPRG1, r4
/* Can't switch the stack pointer until after IVPR is switched,
* because host interrupt handlers would get confused. */
lwz r1, VCPU_GPR(r1)(r4)
/* XXX handle USPRG0 */
/* Host interrupt handlers may have clobbered these guest-readable
* SPRGs, so we need to reload them here with the guest's values. */
lwz r3, VCPU_SPRG4(r4)
mtspr SPRN_SPRG4, r3
lwz r3, VCPU_SPRG5(r4)
mtspr SPRN_SPRG5, r3
lwz r3, VCPU_SPRG6(r4)
mtspr SPRN_SPRG6, r3
lwz r3, VCPU_SPRG7(r4)
mtspr SPRN_SPRG7, r3
#ifdef CONFIG_KVM_EXIT_TIMING
/* save enter time */
1:
mfspr r6, SPRN_TBRU
mfspr r7, SPRN_TBRL
mfspr r8, SPRN_TBRU
cmpw r8, r6
bne 1b
stw r7, VCPU_TIMING_LAST_ENTER_TBL(r4)
stw r8, VCPU_TIMING_LAST_ENTER_TBU(r4)
#endif
/* Finish loading guest volatiles and jump to guest. */
lwz r3, VCPU_CTR(r4)
mtctr r3
lwz r3, VCPU_CR(r4)
mtcr r3
lwz r5, VCPU_GPR(r5)(r4)
lwz r6, VCPU_GPR(r6)(r4)
lwz r7, VCPU_GPR(r7)(r4)
lwz r8, VCPU_GPR(r8)(r4)
lwz r3, VCPU_PC(r4)
mtsrr0 r3
lwz r3, VCPU_MSR(r4)
oris r3, r3, KVMPPC_MSR_MASK@h
ori r3, r3, KVMPPC_MSR_MASK@l
mtsrr1 r3
/* Clear any debug events which occurred since we disabled MSR[DE].
* XXX This gives us a 3-instruction window in which a breakpoint
* intended for guest context could fire in the host instead. */
lis r3, 0xffff
ori r3, r3, 0xffff
mtspr SPRN_DBSR, r3
lwz r3, VCPU_GPR(r3)(r4)
lwz r4, VCPU_GPR(r4)(r4)
rfi
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