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linux/arch/powerpc/kvm/book3s_hv_interrupts.S
Paul Mackerras 8943633cf9 KVM: PPC: Work around POWER7 DABR corruption problem
It turns out that on POWER7, writing to the DABR can cause a corrupted
value to be written if the PMU is active and updating SDAR in continuous
sampling mode.  To work around this, we make sure that the PMU is inactive
and SDAR updates are disabled (via MMCRA) when we are context-switching
DABR.

When the guest sets DABR via the H_SET_DABR hypercall, we use a slightly
different workaround, which is to read back the DABR and write it again
if it got corrupted.

While we are at it, make it consistent that the saving and restoring
of the guest's non-volatile GPRs and the FPRs are done with the guest
setup of the PMU active.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-04-08 14:01:36 +03:00

176 lines
4.5 KiB
ArmAsm

/*
* 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 2011 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
*
* Derived from book3s_interrupts.S, which is:
* 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>
#include <asm/ppc-opcode.h>
/*****************************************************************************
* *
* Guest entry / exit code that is in kernel module memory (vmalloc) *
* *
****************************************************************************/
/* Registers:
* r4: vcpu pointer
*/
_GLOBAL(__kvmppc_vcore_entry)
/* Write correct stack frame */
mflr r0
std r0,PPC_LR_STKOFF(r1)
/* Save host state to the stack */
stdu r1, -SWITCH_FRAME_SIZE(r1)
/* Save non-volatile registers (r14 - r31) and CR */
SAVE_NVGPRS(r1)
mfcr r3
std r3, _CCR(r1)
/* Save host DSCR */
BEGIN_FTR_SECTION
mfspr r3, SPRN_DSCR
std r3, HSTATE_DSCR(r13)
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_206)
/* Save host DABR */
mfspr r3, SPRN_DABR
std r3, HSTATE_DABR(r13)
/* Hard-disable interrupts */
mfmsr r10
std r10, HSTATE_HOST_MSR(r13)
rldicl r10,r10,48,1
rotldi r10,r10,16
mtmsrd r10,1
/* Save host PMU registers */
/* R4 is live here (vcpu pointer) but not r3 or r5 */
li r3, 1
sldi r3, r3, 31 /* MMCR0_FC (freeze counters) bit */
mfspr r7, SPRN_MMCR0 /* save MMCR0 */
mtspr SPRN_MMCR0, r3 /* freeze all counters, disable interrupts */
mfspr r6, SPRN_MMCRA
BEGIN_FTR_SECTION
/* On P7, clear MMCRA in order to disable SDAR updates */
li r5, 0
mtspr SPRN_MMCRA, r5
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_206)
isync
ld r3, PACALPPACAPTR(r13) /* is the host using the PMU? */
lbz r5, LPPACA_PMCINUSE(r3)
cmpwi r5, 0
beq 31f /* skip if not */
mfspr r5, SPRN_MMCR1
std r7, HSTATE_MMCR(r13)
std r5, HSTATE_MMCR + 8(r13)
std r6, HSTATE_MMCR + 16(r13)
mfspr r3, SPRN_PMC1
mfspr r5, SPRN_PMC2
mfspr r6, SPRN_PMC3
mfspr r7, SPRN_PMC4
mfspr r8, SPRN_PMC5
mfspr r9, SPRN_PMC6
BEGIN_FTR_SECTION
mfspr r10, SPRN_PMC7
mfspr r11, SPRN_PMC8
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_201)
stw r3, HSTATE_PMC(r13)
stw r5, HSTATE_PMC + 4(r13)
stw r6, HSTATE_PMC + 8(r13)
stw r7, HSTATE_PMC + 12(r13)
stw r8, HSTATE_PMC + 16(r13)
stw r9, HSTATE_PMC + 20(r13)
BEGIN_FTR_SECTION
stw r10, HSTATE_PMC + 24(r13)
stw r11, HSTATE_PMC + 28(r13)
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_201)
31:
/*
* Put whatever is in the decrementer into the
* hypervisor decrementer.
*/
mfspr r8,SPRN_DEC
mftb r7
mtspr SPRN_HDEC,r8
extsw r8,r8
add r8,r8,r7
std r8,HSTATE_DECEXP(r13)
/*
* On PPC970, if the guest vcpu has an external interrupt pending,
* send ourselves an IPI so as to interrupt the guest once it
* enables interrupts. (It must have interrupts disabled,
* otherwise we would already have delivered the interrupt.)
*/
BEGIN_FTR_SECTION
ld r0, VCPU_PENDING_EXC(r4)
li r7, (1 << BOOK3S_IRQPRIO_EXTERNAL)
oris r7, r7, (1 << BOOK3S_IRQPRIO_EXTERNAL_LEVEL)@h
and. r0, r0, r7
beq 32f
mr r31, r4
lhz r3, PACAPACAINDEX(r13)
bl smp_send_reschedule
nop
mr r4, r31
32:
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_201)
/* Jump to partition switch code */
bl .kvmppc_hv_entry_trampoline
nop
/*
* We return here in virtual mode after the guest exits
* with something that we can't handle in real mode.
* Interrupts are enabled again at this point.
*/
.global kvmppc_handler_highmem
kvmppc_handler_highmem:
/*
* Register usage at this point:
*
* R1 = host R1
* R2 = host R2
* R12 = exit handler id
* R13 = PACA
*/
/* Restore non-volatile host registers (r14 - r31) and CR */
REST_NVGPRS(r1)
ld r4, _CCR(r1)
mtcr r4
addi r1, r1, SWITCH_FRAME_SIZE
ld r0, PPC_LR_STKOFF(r1)
mtlr r0
blr