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linux/arch/powerpc/kvm/emulate.c
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 <linux/jiffies.h>
#include <linux/timer.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kvm_host.h>
#include <asm/reg.h>
#include <asm/time.h>
#include <asm/byteorder.h>
#include <asm/kvm_ppc.h>
#include <asm/disassemble.h>
#include "timing.h"
void kvmppc_emulate_dec(struct kvm_vcpu *vcpu)
{
if (vcpu->arch.tcr & TCR_DIE) {
/* The decrementer ticks at the same rate as the timebase, so
* that's how we convert the guest DEC value to the number of
* host ticks. */
unsigned long nr_jiffies;
nr_jiffies = vcpu->arch.dec / tb_ticks_per_jiffy;
mod_timer(&vcpu->arch.dec_timer,
get_jiffies_64() + nr_jiffies);
} else {
del_timer(&vcpu->arch.dec_timer);
}
}
/* XXX to do:
* lhax
* lhaux
* lswx
* lswi
* stswx
* stswi
* lha
* lhau
* lmw
* stmw
*
* XXX is_bigendian should depend on MMU mapping or MSR[LE]
*/
/* XXX Should probably auto-generate instruction decoding for a particular core
* from opcode tables in the future. */
int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
{
u32 inst = vcpu->arch.last_inst;
u32 ea;
int ra;
int rb;
int rs;
int rt;
int sprn;
enum emulation_result emulated = EMULATE_DONE;
int advance = 1;
/* this default type might be overwritten by subcategories */
kvmppc_set_exit_type(vcpu, EMULATED_INST_EXITS);
switch (get_op(inst)) {
case 3: /* trap */
vcpu->arch.esr |= ESR_PTR;
kvmppc_core_queue_program(vcpu);
advance = 0;
break;
case 31:
switch (get_xop(inst)) {
case 23: /* lwzx */
rt = get_rt(inst);
emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
break;
case 87: /* lbzx */
rt = get_rt(inst);
emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
break;
case 151: /* stwx */
rs = get_rs(inst);
emulated = kvmppc_handle_store(run, vcpu,
vcpu->arch.gpr[rs],
4, 1);
break;
case 215: /* stbx */
rs = get_rs(inst);
emulated = kvmppc_handle_store(run, vcpu,
vcpu->arch.gpr[rs],
1, 1);
break;
case 247: /* stbux */
rs = get_rs(inst);
ra = get_ra(inst);
rb = get_rb(inst);
ea = vcpu->arch.gpr[rb];
if (ra)
ea += vcpu->arch.gpr[ra];
emulated = kvmppc_handle_store(run, vcpu,
vcpu->arch.gpr[rs],
1, 1);
vcpu->arch.gpr[rs] = ea;
break;
case 279: /* lhzx */
rt = get_rt(inst);
emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
break;
case 311: /* lhzux */
rt = get_rt(inst);
ra = get_ra(inst);
rb = get_rb(inst);
ea = vcpu->arch.gpr[rb];
if (ra)
ea += vcpu->arch.gpr[ra];
emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
vcpu->arch.gpr[ra] = ea;
break;
case 339: /* mfspr */
sprn = get_sprn(inst);
rt = get_rt(inst);
switch (sprn) {
case SPRN_SRR0:
vcpu->arch.gpr[rt] = vcpu->arch.srr0; break;
case SPRN_SRR1:
vcpu->arch.gpr[rt] = vcpu->arch.srr1; break;
case SPRN_PVR:
vcpu->arch.gpr[rt] = vcpu->arch.pvr; break;
/* Note: mftb and TBRL/TBWL are user-accessible, so
* the guest can always access the real TB anyways.
* In fact, we probably will never see these traps. */
case SPRN_TBWL:
vcpu->arch.gpr[rt] = mftbl(); break;
case SPRN_TBWU:
vcpu->arch.gpr[rt] = mftbu(); break;
case SPRN_SPRG0:
vcpu->arch.gpr[rt] = vcpu->arch.sprg0; break;
case SPRN_SPRG1:
vcpu->arch.gpr[rt] = vcpu->arch.sprg1; break;
case SPRN_SPRG2:
vcpu->arch.gpr[rt] = vcpu->arch.sprg2; break;
case SPRN_SPRG3:
vcpu->arch.gpr[rt] = vcpu->arch.sprg3; break;
/* Note: SPRG4-7 are user-readable, so we don't get
* a trap. */
default:
emulated = kvmppc_core_emulate_mfspr(vcpu, sprn, rt);
if (emulated == EMULATE_FAIL) {
printk("mfspr: unknown spr %x\n", sprn);
vcpu->arch.gpr[rt] = 0;
}
break;
}
break;
case 407: /* sthx */
rs = get_rs(inst);
ra = get_ra(inst);
rb = get_rb(inst);
emulated = kvmppc_handle_store(run, vcpu,
vcpu->arch.gpr[rs],
2, 1);
break;
case 439: /* sthux */
rs = get_rs(inst);
ra = get_ra(inst);
rb = get_rb(inst);
ea = vcpu->arch.gpr[rb];
if (ra)
ea += vcpu->arch.gpr[ra];
emulated = kvmppc_handle_store(run, vcpu,
vcpu->arch.gpr[rs],
2, 1);
vcpu->arch.gpr[ra] = ea;
break;
case 467: /* mtspr */
sprn = get_sprn(inst);
rs = get_rs(inst);
switch (sprn) {
case SPRN_SRR0:
vcpu->arch.srr0 = vcpu->arch.gpr[rs]; break;
case SPRN_SRR1:
vcpu->arch.srr1 = vcpu->arch.gpr[rs]; break;
/* XXX We need to context-switch the timebase for
* watchdog and FIT. */
case SPRN_TBWL: break;
case SPRN_TBWU: break;
case SPRN_DEC:
vcpu->arch.dec = vcpu->arch.gpr[rs];
kvmppc_emulate_dec(vcpu);
break;
case SPRN_SPRG0:
vcpu->arch.sprg0 = vcpu->arch.gpr[rs]; break;
case SPRN_SPRG1:
vcpu->arch.sprg1 = vcpu->arch.gpr[rs]; break;
case SPRN_SPRG2:
vcpu->arch.sprg2 = vcpu->arch.gpr[rs]; break;
case SPRN_SPRG3:
vcpu->arch.sprg3 = vcpu->arch.gpr[rs]; break;
default:
emulated = kvmppc_core_emulate_mtspr(vcpu, sprn, rs);
if (emulated == EMULATE_FAIL)
printk("mtspr: unknown spr %x\n", sprn);
break;
}
break;
case 470: /* dcbi */
/* Do nothing. The guest is performing dcbi because
* hardware DMA is not snooped by the dcache, but
* emulated DMA either goes through the dcache as
* normal writes, or the host kernel has handled dcache
* coherence. */
break;
case 534: /* lwbrx */
rt = get_rt(inst);
emulated = kvmppc_handle_load(run, vcpu, rt, 4, 0);
break;
case 566: /* tlbsync */
break;
case 662: /* stwbrx */
rs = get_rs(inst);
ra = get_ra(inst);
rb = get_rb(inst);
emulated = kvmppc_handle_store(run, vcpu,
vcpu->arch.gpr[rs],
4, 0);
break;
case 790: /* lhbrx */
rt = get_rt(inst);
emulated = kvmppc_handle_load(run, vcpu, rt, 2, 0);
break;
case 918: /* sthbrx */
rs = get_rs(inst);
ra = get_ra(inst);
rb = get_rb(inst);
emulated = kvmppc_handle_store(run, vcpu,
vcpu->arch.gpr[rs],
2, 0);
break;
default:
/* Attempt core-specific emulation below. */
emulated = EMULATE_FAIL;
}
break;
case 32: /* lwz */
rt = get_rt(inst);
emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
break;
case 33: /* lwzu */
ra = get_ra(inst);
rt = get_rt(inst);
emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
vcpu->arch.gpr[ra] = vcpu->arch.paddr_accessed;
break;
case 34: /* lbz */
rt = get_rt(inst);
emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
break;
case 35: /* lbzu */
ra = get_ra(inst);
rt = get_rt(inst);
emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
vcpu->arch.gpr[ra] = vcpu->arch.paddr_accessed;
break;
case 36: /* stw */
rs = get_rs(inst);
emulated = kvmppc_handle_store(run, vcpu, vcpu->arch.gpr[rs],
4, 1);
break;
case 37: /* stwu */
ra = get_ra(inst);
rs = get_rs(inst);
emulated = kvmppc_handle_store(run, vcpu, vcpu->arch.gpr[rs],
4, 1);
vcpu->arch.gpr[ra] = vcpu->arch.paddr_accessed;
break;
case 38: /* stb */
rs = get_rs(inst);
emulated = kvmppc_handle_store(run, vcpu, vcpu->arch.gpr[rs],
1, 1);
break;
case 39: /* stbu */
ra = get_ra(inst);
rs = get_rs(inst);
emulated = kvmppc_handle_store(run, vcpu, vcpu->arch.gpr[rs],
1, 1);
vcpu->arch.gpr[ra] = vcpu->arch.paddr_accessed;
break;
case 40: /* lhz */
rt = get_rt(inst);
emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
break;
case 41: /* lhzu */
ra = get_ra(inst);
rt = get_rt(inst);
emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
vcpu->arch.gpr[ra] = vcpu->arch.paddr_accessed;
break;
case 44: /* sth */
rs = get_rs(inst);
emulated = kvmppc_handle_store(run, vcpu, vcpu->arch.gpr[rs],
2, 1);
break;
case 45: /* sthu */
ra = get_ra(inst);
rs = get_rs(inst);
emulated = kvmppc_handle_store(run, vcpu, vcpu->arch.gpr[rs],
2, 1);
vcpu->arch.gpr[ra] = vcpu->arch.paddr_accessed;
break;
default:
emulated = EMULATE_FAIL;
}
if (emulated == EMULATE_FAIL) {
emulated = kvmppc_core_emulate_op(run, vcpu, inst, &advance);
if (emulated == EMULATE_FAIL) {
advance = 0;
printk(KERN_ERR "Couldn't emulate instruction 0x%08x "
"(op %d xop %d)\n", inst, get_op(inst), get_xop(inst));
}
}
KVMTRACE_3D(PPC_INSTR, vcpu, inst, (int)vcpu->arch.pc, emulated, entryexit);
if (advance)
vcpu->arch.pc += 4; /* Advance past emulated instruction. */
return emulated;
}
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