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linux/arch/powerpc/kvm/44x_emulate.c
Hollis Blanchard fe4e771d5c KVM: ppc: fix userspace mapping invalidation on context switch 
We used to defer invalidating userspace TLB entries until jumping out of the
kernel. This was causing MMU weirdness most easily triggered by using a pipe in
the guest, e.g. "dmesg | tail". I believe the problem was that after the guest
kernel changed the PID (part of context switch), the old process's mappings
were still present, and so copy_to_user() on the "return to new process" path
ended up using stale mappings.

Testing with large pages (64K) exposed the problem, probably because with 4K
pages, pressure on the TLB faulted all process A's mappings out before the
guest kernel could insert any for process B.

Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31 16:52:26 +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. 2008
*
* Authors: Hollis Blanchard <hollisb@us.ibm.com>
*/
#include <asm/kvm_ppc.h>
#include <asm/dcr.h>
#include <asm/dcr-regs.h>
#include <asm/disassemble.h>
#include <asm/kvm_44x.h>
#include "booke.h"
#include "44x_tlb.h"
#define OP_RFI 19
#define XOP_RFI 50
#define XOP_MFMSR 83
#define XOP_WRTEE 131
#define XOP_MTMSR 146
#define XOP_WRTEEI 163
#define XOP_MFDCR 323
#define XOP_MTDCR 451
#define XOP_TLBSX 914
#define XOP_ICCCI 966
#define XOP_TLBWE 978
static void kvmppc_emul_rfi(struct kvm_vcpu *vcpu)
{
vcpu->arch.pc = vcpu->arch.srr0;
kvmppc_set_msr(vcpu, vcpu->arch.srr1);
}
int kvmppc_core_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu,
unsigned int inst, int *advance)
{
int emulated = EMULATE_DONE;
int dcrn;
int ra;
int rb;
int rc;
int rs;
int rt;
int ws;
switch (get_op(inst)) {
case OP_RFI:
switch (get_xop(inst)) {
case XOP_RFI:
kvmppc_emul_rfi(vcpu);
*advance = 0;
break;
default:
emulated = EMULATE_FAIL;
break;
}
break;
case 31:
switch (get_xop(inst)) {
case XOP_MFMSR:
rt = get_rt(inst);
vcpu->arch.gpr[rt] = vcpu->arch.msr;
break;
case XOP_MTMSR:
rs = get_rs(inst);
kvmppc_set_msr(vcpu, vcpu->arch.gpr[rs]);
break;
case XOP_WRTEE:
rs = get_rs(inst);
vcpu->arch.msr = (vcpu->arch.msr & ~MSR_EE)
| (vcpu->arch.gpr[rs] & MSR_EE);
break;
case XOP_WRTEEI:
vcpu->arch.msr = (vcpu->arch.msr & ~MSR_EE)
| (inst & MSR_EE);
break;
case XOP_MFDCR:
dcrn = get_dcrn(inst);
rt = get_rt(inst);
/* The guest may access CPR0 registers to determine the timebase
* frequency, and it must know the real host frequency because it
* can directly access the timebase registers.
*
* It would be possible to emulate those accesses in userspace,
* but userspace can really only figure out the end frequency.
* We could decompose that into the factors that compute it, but
* that's tricky math, and it's easier to just report the real
* CPR0 values.
*/
switch (dcrn) {
case DCRN_CPR0_CONFIG_ADDR:
vcpu->arch.gpr[rt] = vcpu->arch.cpr0_cfgaddr;
break;
case DCRN_CPR0_CONFIG_DATA:
local_irq_disable();
mtdcr(DCRN_CPR0_CONFIG_ADDR,
vcpu->arch.cpr0_cfgaddr);
vcpu->arch.gpr[rt] = mfdcr(DCRN_CPR0_CONFIG_DATA);
local_irq_enable();
break;
default:
run->dcr.dcrn = dcrn;
run->dcr.data = 0;
run->dcr.is_write = 0;
vcpu->arch.io_gpr = rt;
vcpu->arch.dcr_needed = 1;
emulated = EMULATE_DO_DCR;
}
break;
case XOP_MTDCR:
dcrn = get_dcrn(inst);
rs = get_rs(inst);
/* emulate some access in kernel */
switch (dcrn) {
case DCRN_CPR0_CONFIG_ADDR:
vcpu->arch.cpr0_cfgaddr = vcpu->arch.gpr[rs];
break;
default:
run->dcr.dcrn = dcrn;
run->dcr.data = vcpu->arch.gpr[rs];
run->dcr.is_write = 1;
vcpu->arch.dcr_needed = 1;
emulated = EMULATE_DO_DCR;
}
break;
case XOP_TLBWE:
ra = get_ra(inst);
rs = get_rs(inst);
ws = get_ws(inst);
emulated = kvmppc_44x_emul_tlbwe(vcpu, ra, rs, ws);
break;
case XOP_TLBSX:
rt = get_rt(inst);
ra = get_ra(inst);
rb = get_rb(inst);
rc = get_rc(inst);
emulated = kvmppc_44x_emul_tlbsx(vcpu, rt, ra, rb, rc);
break;
case XOP_ICCCI:
break;
default:
emulated = EMULATE_FAIL;
}
break;
default:
emulated = EMULATE_FAIL;
}
return emulated;
}
int kvmppc_core_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, int rs)
{
switch (sprn) {
case SPRN_MMUCR:
vcpu->arch.mmucr = vcpu->arch.gpr[rs]; break;
case SPRN_PID:
kvmppc_set_pid(vcpu, vcpu->arch.gpr[rs]); break;
case SPRN_CCR0:
vcpu->arch.ccr0 = vcpu->arch.gpr[rs]; break;
case SPRN_CCR1:
vcpu->arch.ccr1 = vcpu->arch.gpr[rs]; break;
case SPRN_DEAR:
vcpu->arch.dear = vcpu->arch.gpr[rs]; break;
case SPRN_ESR:
vcpu->arch.esr = vcpu->arch.gpr[rs]; break;
case SPRN_DBCR0:
vcpu->arch.dbcr0 = vcpu->arch.gpr[rs]; break;
case SPRN_DBCR1:
vcpu->arch.dbcr1 = vcpu->arch.gpr[rs]; break;
case SPRN_TSR:
vcpu->arch.tsr &= ~vcpu->arch.gpr[rs]; break;
case SPRN_TCR:
vcpu->arch.tcr = vcpu->arch.gpr[rs];
kvmppc_emulate_dec(vcpu);
break;
/* Note: SPRG4-7 are user-readable. These values are
* loaded into the real SPRGs when resuming the
* guest. */
case SPRN_SPRG4:
vcpu->arch.sprg4 = vcpu->arch.gpr[rs]; break;
case SPRN_SPRG5:
vcpu->arch.sprg5 = vcpu->arch.gpr[rs]; break;
case SPRN_SPRG6:
vcpu->arch.sprg6 = vcpu->arch.gpr[rs]; break;
case SPRN_SPRG7:
vcpu->arch.sprg7 = vcpu->arch.gpr[rs]; break;
case SPRN_IVPR:
vcpu->arch.ivpr = vcpu->arch.gpr[rs];
break;
case SPRN_IVOR0:
vcpu->arch.ivor[BOOKE_IRQPRIO_CRITICAL] = vcpu->arch.gpr[rs];
break;
case SPRN_IVOR1:
vcpu->arch.ivor[BOOKE_IRQPRIO_MACHINE_CHECK] = vcpu->arch.gpr[rs];
break;
case SPRN_IVOR2:
vcpu->arch.ivor[BOOKE_IRQPRIO_DATA_STORAGE] = vcpu->arch.gpr[rs];
break;
case SPRN_IVOR3:
vcpu->arch.ivor[BOOKE_IRQPRIO_INST_STORAGE] = vcpu->arch.gpr[rs];
break;
case SPRN_IVOR4:
vcpu->arch.ivor[BOOKE_IRQPRIO_EXTERNAL] = vcpu->arch.gpr[rs];
break;
case SPRN_IVOR5:
vcpu->arch.ivor[BOOKE_IRQPRIO_ALIGNMENT] = vcpu->arch.gpr[rs];
break;
case SPRN_IVOR6:
vcpu->arch.ivor[BOOKE_IRQPRIO_PROGRAM] = vcpu->arch.gpr[rs];
break;
case SPRN_IVOR7:
vcpu->arch.ivor[BOOKE_IRQPRIO_FP_UNAVAIL] = vcpu->arch.gpr[rs];
break;
case SPRN_IVOR8:
vcpu->arch.ivor[BOOKE_IRQPRIO_SYSCALL] = vcpu->arch.gpr[rs];
break;
case SPRN_IVOR9:
vcpu->arch.ivor[BOOKE_IRQPRIO_AP_UNAVAIL] = vcpu->arch.gpr[rs];
break;
case SPRN_IVOR10:
vcpu->arch.ivor[BOOKE_IRQPRIO_DECREMENTER] = vcpu->arch.gpr[rs];
break;
case SPRN_IVOR11:
vcpu->arch.ivor[BOOKE_IRQPRIO_FIT] = vcpu->arch.gpr[rs];
break;
case SPRN_IVOR12:
vcpu->arch.ivor[BOOKE_IRQPRIO_WATCHDOG] = vcpu->arch.gpr[rs];
break;
case SPRN_IVOR13:
vcpu->arch.ivor[BOOKE_IRQPRIO_DTLB_MISS] = vcpu->arch.gpr[rs];
break;
case SPRN_IVOR14:
vcpu->arch.ivor[BOOKE_IRQPRIO_ITLB_MISS] = vcpu->arch.gpr[rs];
break;
case SPRN_IVOR15:
vcpu->arch.ivor[BOOKE_IRQPRIO_DEBUG] = vcpu->arch.gpr[rs];
break;
default:
return EMULATE_FAIL;
}
return EMULATE_DONE;
}
int kvmppc_core_emulate_mfspr(struct kvm_vcpu *vcpu, int sprn, int rt)
{
switch (sprn) {
/* 440 */
case SPRN_MMUCR:
vcpu->arch.gpr[rt] = vcpu->arch.mmucr; break;
case SPRN_CCR0:
vcpu->arch.gpr[rt] = vcpu->arch.ccr0; break;
case SPRN_CCR1:
vcpu->arch.gpr[rt] = vcpu->arch.ccr1; break;
/* Book E */
case SPRN_PID:
vcpu->arch.gpr[rt] = vcpu->arch.pid; break;
case SPRN_IVPR:
vcpu->arch.gpr[rt] = vcpu->arch.ivpr; break;
case SPRN_DEAR:
vcpu->arch.gpr[rt] = vcpu->arch.dear; break;
case SPRN_ESR:
vcpu->arch.gpr[rt] = vcpu->arch.esr; break;
case SPRN_DBCR0:
vcpu->arch.gpr[rt] = vcpu->arch.dbcr0; break;
case SPRN_DBCR1:
vcpu->arch.gpr[rt] = vcpu->arch.dbcr1; break;
case SPRN_IVOR0:
vcpu->arch.gpr[rt] = vcpu->arch.ivor[BOOKE_IRQPRIO_CRITICAL];
break;
case SPRN_IVOR1:
vcpu->arch.gpr[rt] = vcpu->arch.ivor[BOOKE_IRQPRIO_MACHINE_CHECK];
break;
case SPRN_IVOR2:
vcpu->arch.gpr[rt] = vcpu->arch.ivor[BOOKE_IRQPRIO_DATA_STORAGE];
break;
case SPRN_IVOR3:
vcpu->arch.gpr[rt] = vcpu->arch.ivor[BOOKE_IRQPRIO_INST_STORAGE];
break;
case SPRN_IVOR4:
vcpu->arch.gpr[rt] = vcpu->arch.ivor[BOOKE_IRQPRIO_EXTERNAL];
break;
case SPRN_IVOR5:
vcpu->arch.gpr[rt] = vcpu->arch.ivor[BOOKE_IRQPRIO_ALIGNMENT];
break;
case SPRN_IVOR6:
vcpu->arch.gpr[rt] = vcpu->arch.ivor[BOOKE_IRQPRIO_PROGRAM];
break;
case SPRN_IVOR7:
vcpu->arch.gpr[rt] = vcpu->arch.ivor[BOOKE_IRQPRIO_FP_UNAVAIL];
break;
case SPRN_IVOR8:
vcpu->arch.gpr[rt] = vcpu->arch.ivor[BOOKE_IRQPRIO_SYSCALL];
break;
case SPRN_IVOR9:
vcpu->arch.gpr[rt] = vcpu->arch.ivor[BOOKE_IRQPRIO_AP_UNAVAIL];
break;
case SPRN_IVOR10:
vcpu->arch.gpr[rt] = vcpu->arch.ivor[BOOKE_IRQPRIO_DECREMENTER];
break;
case SPRN_IVOR11:
vcpu->arch.gpr[rt] = vcpu->arch.ivor[BOOKE_IRQPRIO_FIT];
break;
case SPRN_IVOR12:
vcpu->arch.gpr[rt] = vcpu->arch.ivor[BOOKE_IRQPRIO_WATCHDOG];
break;
case SPRN_IVOR13:
vcpu->arch.gpr[rt] = vcpu->arch.ivor[BOOKE_IRQPRIO_DTLB_MISS];
break;
case SPRN_IVOR14:
vcpu->arch.gpr[rt] = vcpu->arch.ivor[BOOKE_IRQPRIO_ITLB_MISS];
break;
case SPRN_IVOR15:
vcpu->arch.gpr[rt] = vcpu->arch.ivor[BOOKE_IRQPRIO_DEBUG];
break;
default:
return EMULATE_FAIL;
}
return EMULATE_DONE;
}
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