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linux/arch/powerpc/kvm/book3s_64_slb.S

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Add SLB switching code for entry/exit This is the really low level of guest entry/exit code. Book3s_64 has an SLB, which stores all ESID -> VSID mappings we're currently aware of. The segments in the guest differ from the ones on the host, so we need to switch the SLB to tell the MMU that we're in a new context. So we store a shadow of the guest's SLB in the PACA, switch to that on entry and only restore bolted entries on exit, leaving the rest to the Linux SLB fault handler. That way we get a really clean way of switching the SLB. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-11-02 20:02:29 +08:00
/*
* 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>
*/
#define SHADOW_SLB_ESID(num) (SLBSHADOW_SAVEAREA + (num * 0x10))
#define SHADOW_SLB_VSID(num) (SLBSHADOW_SAVEAREA + (num * 0x10) + 0x8)
#define UNBOLT_SLB_ENTRY(num) \
ld r9, SHADOW_SLB_ESID(num)(r12); \
/* Invalid? Skip. */; \
rldicl. r0, r9, 37, 63; \
beq slb_entry_skip_ ## num; \
xoris r9, r9, SLB_ESID_V@h; \
std r9, SHADOW_SLB_ESID(num)(r12); \
slb_entry_skip_ ## num:
#define REBOLT_SLB_ENTRY(num) \
ld r10, SHADOW_SLB_ESID(num)(r11); \
cmpdi r10, 0; \
KVM: PPC: Fix typo in rebolting code When we're loading bolted entries into the SLB again, we're checking if an entry is in use and only slbmte it when it is. Unfortunately, the check always goes to the skip label of the first entry, resulting in an endless loop when it actually gets triggered. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-01-05 05:19:22 +08:00
beq slb_exit_skip_ ## num; \
Add SLB switching code for entry/exit This is the really low level of guest entry/exit code. Book3s_64 has an SLB, which stores all ESID -> VSID mappings we're currently aware of. The segments in the guest differ from the ones on the host, so we need to switch the SLB to tell the MMU that we're in a new context. So we store a shadow of the guest's SLB in the PACA, switch to that on entry and only restore bolted entries on exit, leaving the rest to the Linux SLB fault handler. That way we get a really clean way of switching the SLB. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-11-02 20:02:29 +08:00
oris r10, r10, SLB_ESID_V@h; \
ld r9, SHADOW_SLB_VSID(num)(r11); \
slbmte r9, r10; \
std r10, SHADOW_SLB_ESID(num)(r11); \
slb_exit_skip_ ## num:
/******************************************************************************
* *
* Entry code *
* *
*****************************************************************************/
.global kvmppc_handler_trampoline_enter
kvmppc_handler_trampoline_enter:
/* Required state:
*
* MSR = ~IR|DR
* R13 = PACA
KVM: PPC: Use PACA backed shadow vcpu We're being horribly racy right now. All the entry and exit code hijacks random fields from the PACA that could easily be used by different code in case we get interrupted, for example by a #MC or even page fault. After discussing this with Ben, we figured it's best to reserve some more space in the PACA and just shove off some vcpu state to there. That way we can drastically improve the readability of the code, make it less racy and less complex. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-01-08 09:58:03 +08:00
* R1 = host R1
* R2 = host R2
Add SLB switching code for entry/exit This is the really low level of guest entry/exit code. Book3s_64 has an SLB, which stores all ESID -> VSID mappings we're currently aware of. The segments in the guest differ from the ones on the host, so we need to switch the SLB to tell the MMU that we're in a new context. So we store a shadow of the guest's SLB in the PACA, switch to that on entry and only restore bolted entries on exit, leaving the rest to the Linux SLB fault handler. That way we get a really clean way of switching the SLB. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-11-02 20:02:29 +08:00
* R9 = guest IP
* R10 = guest MSR
KVM: PPC: Use PACA backed shadow vcpu We're being horribly racy right now. All the entry and exit code hijacks random fields from the PACA that could easily be used by different code in case we get interrupted, for example by a #MC or even page fault. After discussing this with Ben, we figured it's best to reserve some more space in the PACA and just shove off some vcpu state to there. That way we can drastically improve the readability of the code, make it less racy and less complex. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-01-08 09:58:03 +08:00
* all other GPRS = free
* PACA[KVM_CR] = guest CR
* PACA[KVM_XER] = guest XER
Add SLB switching code for entry/exit This is the really low level of guest entry/exit code. Book3s_64 has an SLB, which stores all ESID -> VSID mappings we're currently aware of. The segments in the guest differ from the ones on the host, so we need to switch the SLB to tell the MMU that we're in a new context. So we store a shadow of the guest's SLB in the PACA, switch to that on entry and only restore bolted entries on exit, leaving the rest to the Linux SLB fault handler. That way we get a really clean way of switching the SLB. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-11-02 20:02:29 +08:00
*/
mtsrr0 r9
mtsrr1 r10
KVM: PPC: Call SLB patching code in interrupt safe manner Currently we're racy when doing the transition from IR=1 to IR=0, from the module memory entry code to the real mode SLB switching code. To work around that I took a look at the RTAS entry code which is faced with a similar problem and did the same thing: A small helper in linear mapped memory that does mtmsr with IR=0 and then RFIs info the actual handler. Thanks to that trick we can safely take page faults in the entry code and only need to be really wary of what to do as of the SLB switching part. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-01-08 09:58:06 +08:00
/* Activate guest mode, so faults get handled by KVM */
li r11, KVM_GUEST_MODE_GUEST
stb r11, PACA_KVM_IN_GUEST(r13)
Add SLB switching code for entry/exit This is the really low level of guest entry/exit code. Book3s_64 has an SLB, which stores all ESID -> VSID mappings we're currently aware of. The segments in the guest differ from the ones on the host, so we need to switch the SLB to tell the MMU that we're in a new context. So we store a shadow of the guest's SLB in the PACA, switch to that on entry and only restore bolted entries on exit, leaving the rest to the Linux SLB fault handler. That way we get a really clean way of switching the SLB. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-11-02 20:02:29 +08:00
/* Remove LPAR shadow entries */
#if SLB_NUM_BOLTED == 3
ld r12, PACA_SLBSHADOWPTR(r13)
/* Save off the first entry so we can slbie it later */
ld r10, SHADOW_SLB_ESID(0)(r12)
ld r11, SHADOW_SLB_VSID(0)(r12)
/* Remove bolted entries */
UNBOLT_SLB_ENTRY(0)
UNBOLT_SLB_ENTRY(1)
UNBOLT_SLB_ENTRY(2)
#else
#error unknown number of bolted entries
#endif
/* Flush SLB */
slbia
/* r0 = esid & ESID_MASK */
rldicr r10, r10, 0, 35
/* r0 |= CLASS_BIT(VSID) */
rldic r12, r11, 56 - 36, 36
or r10, r10, r12
slbie r10
isync
/* Fill SLB with our shadow */
lbz r12, PACA_KVM_SLB_MAX(r13)
mulli r12, r12, 16
addi r12, r12, PACA_KVM_SLB
add r12, r12, r13
/* for (r11 = kvm_slb; r11 < kvm_slb + kvm_slb_size; r11+=slb_entry) */
li r11, PACA_KVM_SLB
add r11, r11, r13
slb_loop_enter:
ld r10, 0(r11)
rldicl. r0, r10, 37, 63
beq slb_loop_enter_skip
ld r9, 8(r11)
slbmte r9, r10
slb_loop_enter_skip:
addi r11, r11, 16
cmpd cr0, r11, r12
blt slb_loop_enter
slb_do_enter:
/* Enter guest */
KVM: PPC: Use PACA backed shadow vcpu We're being horribly racy right now. All the entry and exit code hijacks random fields from the PACA that could easily be used by different code in case we get interrupted, for example by a #MC or even page fault. After discussing this with Ben, we figured it's best to reserve some more space in the PACA and just shove off some vcpu state to there. That way we can drastically improve the readability of the code, make it less racy and less complex. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-01-08 09:58:03 +08:00
ld r0, (PACA_KVM_R0)(r13)
ld r1, (PACA_KVM_R1)(r13)
ld r2, (PACA_KVM_R2)(r13)
ld r3, (PACA_KVM_R3)(r13)
ld r4, (PACA_KVM_R4)(r13)
ld r5, (PACA_KVM_R5)(r13)
ld r6, (PACA_KVM_R6)(r13)
ld r7, (PACA_KVM_R7)(r13)
ld r8, (PACA_KVM_R8)(r13)
ld r9, (PACA_KVM_R9)(r13)
ld r10, (PACA_KVM_R10)(r13)
ld r12, (PACA_KVM_R12)(r13)
lwz r11, (PACA_KVM_CR)(r13)
Add SLB switching code for entry/exit This is the really low level of guest entry/exit code. Book3s_64 has an SLB, which stores all ESID -> VSID mappings we're currently aware of. The segments in the guest differ from the ones on the host, so we need to switch the SLB to tell the MMU that we're in a new context. So we store a shadow of the guest's SLB in the PACA, switch to that on entry and only restore bolted entries on exit, leaving the rest to the Linux SLB fault handler. That way we get a really clean way of switching the SLB. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-11-02 20:02:29 +08:00
mtcr r11
KVM: PPC: Make XER load 32 bit We have a 32 bit value in the PACA to store XER in. We also do an stw when storing XER in there. But then we load it with ld, completely screwing it up on every entry. Welcome to the Big Endian world. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-03-25 04:48:26 +08:00
lwz r11, (PACA_KVM_XER)(r13)
Add SLB switching code for entry/exit This is the really low level of guest entry/exit code. Book3s_64 has an SLB, which stores all ESID -> VSID mappings we're currently aware of. The segments in the guest differ from the ones on the host, so we need to switch the SLB to tell the MMU that we're in a new context. So we store a shadow of the guest's SLB in the PACA, switch to that on entry and only restore bolted entries on exit, leaving the rest to the Linux SLB fault handler. That way we get a really clean way of switching the SLB. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-11-02 20:02:29 +08:00
mtxer r11
KVM: PPC: Use PACA backed shadow vcpu We're being horribly racy right now. All the entry and exit code hijacks random fields from the PACA that could easily be used by different code in case we get interrupted, for example by a #MC or even page fault. After discussing this with Ben, we figured it's best to reserve some more space in the PACA and just shove off some vcpu state to there. That way we can drastically improve the readability of the code, make it less racy and less complex. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-01-08 09:58:03 +08:00
ld r11, (PACA_KVM_R11)(r13)
ld r13, (PACA_KVM_R13)(r13)
Add SLB switching code for entry/exit This is the really low level of guest entry/exit code. Book3s_64 has an SLB, which stores all ESID -> VSID mappings we're currently aware of. The segments in the guest differ from the ones on the host, so we need to switch the SLB to tell the MMU that we're in a new context. So we store a shadow of the guest's SLB in the PACA, switch to that on entry and only restore bolted entries on exit, leaving the rest to the Linux SLB fault handler. That way we get a really clean way of switching the SLB. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-11-02 20:02:29 +08:00
RFI
kvmppc_handler_trampoline_enter_end:
/******************************************************************************
* *
* Exit code *
* *
*****************************************************************************/
.global kvmppc_handler_trampoline_exit
kvmppc_handler_trampoline_exit:
/* Register usage at this point:
*
KVM: PPC: Use PACA backed shadow vcpu We're being horribly racy right now. All the entry and exit code hijacks random fields from the PACA that could easily be used by different code in case we get interrupted, for example by a #MC or even page fault. After discussing this with Ben, we figured it's best to reserve some more space in the PACA and just shove off some vcpu state to there. That way we can drastically improve the readability of the code, make it less racy and less complex. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-01-08 09:58:03 +08:00
* SPRG_SCRATCH0 = guest R13
* R12 = exit handler id
* R13 = PACA
* PACA.KVM.SCRATCH0 = guest R12
* PACA.KVM.SCRATCH1 = guest CR
Add SLB switching code for entry/exit This is the really low level of guest entry/exit code. Book3s_64 has an SLB, which stores all ESID -> VSID mappings we're currently aware of. The segments in the guest differ from the ones on the host, so we need to switch the SLB to tell the MMU that we're in a new context. So we store a shadow of the guest's SLB in the PACA, switch to that on entry and only restore bolted entries on exit, leaving the rest to the Linux SLB fault handler. That way we get a really clean way of switching the SLB. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-11-02 20:02:29 +08:00
*
*/
/* Save registers */
KVM: PPC: Use PACA backed shadow vcpu We're being horribly racy right now. All the entry and exit code hijacks random fields from the PACA that could easily be used by different code in case we get interrupted, for example by a #MC or even page fault. After discussing this with Ben, we figured it's best to reserve some more space in the PACA and just shove off some vcpu state to there. That way we can drastically improve the readability of the code, make it less racy and less complex. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-01-08 09:58:03 +08:00
std r0, PACA_KVM_R0(r13)
std r1, PACA_KVM_R1(r13)
std r2, PACA_KVM_R2(r13)
std r3, PACA_KVM_R3(r13)
std r4, PACA_KVM_R4(r13)
std r5, PACA_KVM_R5(r13)
std r6, PACA_KVM_R6(r13)
std r7, PACA_KVM_R7(r13)
std r8, PACA_KVM_R8(r13)
std r9, PACA_KVM_R9(r13)
std r10, PACA_KVM_R10(r13)
std r11, PACA_KVM_R11(r13)
/* Restore R1/R2 so we can handle faults */
ld r1, PACA_KVM_HOST_R1(r13)
ld r2, PACA_KVM_HOST_R2(r13)
/* Save guest PC and MSR in GPRs */
mfsrr0 r3
mfsrr1 r4
/* Get scratch'ed off registers */
mfspr r9, SPRN_SPRG_SCRATCH0
std r9, PACA_KVM_R13(r13)
ld r8, PACA_KVM_SCRATCH0(r13)
std r8, PACA_KVM_R12(r13)
lwz r7, PACA_KVM_SCRATCH1(r13)
stw r7, PACA_KVM_CR(r13)
/* Save more register state */
mfxer r6
stw r6, PACA_KVM_XER(r13)
mfdar r5
mfdsisr r6
Add SLB switching code for entry/exit This is the really low level of guest entry/exit code. Book3s_64 has an SLB, which stores all ESID -> VSID mappings we're currently aware of. The segments in the guest differ from the ones on the host, so we need to switch the SLB to tell the MMU that we're in a new context. So we store a shadow of the guest's SLB in the PACA, switch to that on entry and only restore bolted entries on exit, leaving the rest to the Linux SLB fault handler. That way we get a really clean way of switching the SLB. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-11-02 20:02:29 +08:00
/*
* In order for us to easily get the last instruction,
* we got the #vmexit at, we exploit the fact that the
* virtual layout is still the same here, so we can just
* ld from the guest's PC address
*/
/* We only load the last instruction when it's safe */
cmpwi r12, BOOK3S_INTERRUPT_DATA_STORAGE
beq ld_last_inst
cmpwi r12, BOOK3S_INTERRUPT_PROGRAM
beq ld_last_inst
b no_ld_last_inst
ld_last_inst:
/* Save off the guest instruction we're at */
KVM: PPC: Implement 'skip instruction' mode To fetch the last instruction we were interrupted on, we enable DR in early exit code, where we are still in a very transitional phase between guest and host state. Most of the time this seemed to work, but another CPU can easily flush our TLB and HTAB which makes us go in the Linux page fault handler which totally breaks because we still use the guest's SLB entries. To work around that, let's introduce a second KVM guest mode that defines that whenever we get a trap, we don't call the Linux handler or go into the KVM exit code, but just jump over the faulting instruction. That way a potentially bad lwz doesn't trigger any faults and we can later on interpret the invalid instruction we fetched as "fetch didn't work". Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-01-08 09:58:04 +08:00
/* Set guest mode to 'jump over instruction' so if lwz faults
* we'll just continue at the next IP. */
li r9, KVM_GUEST_MODE_SKIP
stb r9, PACA_KVM_IN_GUEST(r13)
Add SLB switching code for entry/exit This is the really low level of guest entry/exit code. Book3s_64 has an SLB, which stores all ESID -> VSID mappings we're currently aware of. The segments in the guest differ from the ones on the host, so we need to switch the SLB to tell the MMU that we're in a new context. So we store a shadow of the guest's SLB in the PACA, switch to that on entry and only restore bolted entries on exit, leaving the rest to the Linux SLB fault handler. That way we get a really clean way of switching the SLB. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-11-02 20:02:29 +08:00
/* 1) enable paging for data */
mfmsr r9
ori r11, r9, MSR_DR /* Enable paging for data */
mtmsr r11
/* 2) fetch the instruction */
KVM: PPC: Implement 'skip instruction' mode To fetch the last instruction we were interrupted on, we enable DR in early exit code, where we are still in a very transitional phase between guest and host state. Most of the time this seemed to work, but another CPU can easily flush our TLB and HTAB which makes us go in the Linux page fault handler which totally breaks because we still use the guest's SLB entries. To work around that, let's introduce a second KVM guest mode that defines that whenever we get a trap, we don't call the Linux handler or go into the KVM exit code, but just jump over the faulting instruction. That way a potentially bad lwz doesn't trigger any faults and we can later on interpret the invalid instruction we fetched as "fetch didn't work". Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-01-08 09:58:04 +08:00
li r0, KVM_INST_FETCH_FAILED /* In case lwz faults */
KVM: PPC: Use PACA backed shadow vcpu We're being horribly racy right now. All the entry and exit code hijacks random fields from the PACA that could easily be used by different code in case we get interrupted, for example by a #MC or even page fault. After discussing this with Ben, we figured it's best to reserve some more space in the PACA and just shove off some vcpu state to there. That way we can drastically improve the readability of the code, make it less racy and less complex. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-01-08 09:58:03 +08:00
lwz r0, 0(r3)
Add SLB switching code for entry/exit This is the really low level of guest entry/exit code. Book3s_64 has an SLB, which stores all ESID -> VSID mappings we're currently aware of. The segments in the guest differ from the ones on the host, so we need to switch the SLB to tell the MMU that we're in a new context. So we store a shadow of the guest's SLB in the PACA, switch to that on entry and only restore bolted entries on exit, leaving the rest to the Linux SLB fault handler. That way we get a really clean way of switching the SLB. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-11-02 20:02:29 +08:00
/* 3) disable paging again */
mtmsr r9
no_ld_last_inst:
KVM: PPC: Implement 'skip instruction' mode To fetch the last instruction we were interrupted on, we enable DR in early exit code, where we are still in a very transitional phase between guest and host state. Most of the time this seemed to work, but another CPU can easily flush our TLB and HTAB which makes us go in the Linux page fault handler which totally breaks because we still use the guest's SLB entries. To work around that, let's introduce a second KVM guest mode that defines that whenever we get a trap, we don't call the Linux handler or go into the KVM exit code, but just jump over the faulting instruction. That way a potentially bad lwz doesn't trigger any faults and we can later on interpret the invalid instruction we fetched as "fetch didn't work". Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-01-08 09:58:04 +08:00
/* Unset guest mode */
li r9, KVM_GUEST_MODE_NONE
stb r9, PACA_KVM_IN_GUEST(r13)
Add SLB switching code for entry/exit This is the really low level of guest entry/exit code. Book3s_64 has an SLB, which stores all ESID -> VSID mappings we're currently aware of. The segments in the guest differ from the ones on the host, so we need to switch the SLB to tell the MMU that we're in a new context. So we store a shadow of the guest's SLB in the PACA, switch to that on entry and only restore bolted entries on exit, leaving the rest to the Linux SLB fault handler. That way we get a really clean way of switching the SLB. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-11-02 20:02:29 +08:00
/* Restore bolted entries from the shadow and fix it along the way */
/* We don't store anything in entry 0, so we don't need to take care of it */
slbia
isync
#if SLB_NUM_BOLTED == 3
ld r11, PACA_SLBSHADOWPTR(r13)
REBOLT_SLB_ENTRY(0)
REBOLT_SLB_ENTRY(1)
REBOLT_SLB_ENTRY(2)
#else
#error unknown number of bolted entries
#endif
slb_do_exit:
KVM: PPC: Use PACA backed shadow vcpu We're being horribly racy right now. All the entry and exit code hijacks random fields from the PACA that could easily be used by different code in case we get interrupted, for example by a #MC or even page fault. After discussing this with Ben, we figured it's best to reserve some more space in the PACA and just shove off some vcpu state to there. That way we can drastically improve the readability of the code, make it less racy and less complex. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-01-08 09:58:03 +08:00
/* Register usage at this point:
*
* R0 = guest last inst
* R1 = host R1
* R2 = host R2
* R3 = guest PC
* R4 = guest MSR
* R5 = guest DAR
* R6 = guest DSISR
* R12 = exit handler id
* R13 = PACA
* PACA.KVM.* = guest *
*
*/
Add SLB switching code for entry/exit This is the really low level of guest entry/exit code. Book3s_64 has an SLB, which stores all ESID -> VSID mappings we're currently aware of. The segments in the guest differ from the ones on the host, so we need to switch the SLB to tell the MMU that we're in a new context. So we store a shadow of the guest's SLB in the PACA, switch to that on entry and only restore bolted entries on exit, leaving the rest to the Linux SLB fault handler. That way we get a really clean way of switching the SLB. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-11-02 20:02:29 +08:00
/* RFI into the highmem handler */
KVM: PPC: Use PACA backed shadow vcpu We're being horribly racy right now. All the entry and exit code hijacks random fields from the PACA that could easily be used by different code in case we get interrupted, for example by a #MC or even page fault. After discussing this with Ben, we figured it's best to reserve some more space in the PACA and just shove off some vcpu state to there. That way we can drastically improve the readability of the code, make it less racy and less complex. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-01-08 09:58:03 +08:00
mfmsr r7
ori r7, r7, MSR_IR|MSR_DR|MSR_RI /* Enable paging */
mtsrr1 r7
ld r8, PACA_KVM_VMHANDLER(r13) /* Highmem handler address */
mtsrr0 r8
Add SLB switching code for entry/exit This is the really low level of guest entry/exit code. Book3s_64 has an SLB, which stores all ESID -> VSID mappings we're currently aware of. The segments in the guest differ from the ones on the host, so we need to switch the SLB to tell the MMU that we're in a new context. So we store a shadow of the guest's SLB in the PACA, switch to that on entry and only restore bolted entries on exit, leaving the rest to the Linux SLB fault handler. That way we get a really clean way of switching the SLB. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-11-02 20:02:29 +08:00
RFI
kvmppc_handler_trampoline_exit_end:
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