linux-stable-rt/arch/powerpc/kvm/book3s_segment.S

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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 SUSE Linux Products GmbH 2010
*
* Authors: Alexander Graf <agraf@suse.de>
*/
/* Real mode helpers */
#if defined(CONFIG_PPC_BOOK3S_64)
#define GET_SHADOW_VCPU(reg) \
mr reg, r13
#elif defined(CONFIG_PPC_BOOK3S_32)
#define GET_SHADOW_VCPU(reg) \
tophys(reg, r2); \
lwz reg, (THREAD + THREAD_KVM_SVCPU)(reg); \
tophys(reg, reg)
#endif
/* Disable for nested KVM */
#define USE_QUICK_LAST_INST
/* Get helper functions for subarch specific functionality */
#if defined(CONFIG_PPC_BOOK3S_64)
#include "book3s_64_slb.S"
#elif defined(CONFIG_PPC_BOOK3S_32)
#include "book3s_32_sr.S"
#endif
/******************************************************************************
* *
* Entry code *
* *
*****************************************************************************/
.global kvmppc_handler_trampoline_enter
kvmppc_handler_trampoline_enter:
/* Required state:
*
* MSR = ~IR|DR
* R13 = PACA
* R1 = host R1
* R2 = host R2
* R10 = guest MSR
* all other volatile GPRS = free
* SVCPU[CR] = guest CR
* SVCPU[XER] = guest XER
* SVCPU[CTR] = guest CTR
* SVCPU[LR] = guest LR
*/
/* r3 = shadow vcpu */
GET_SHADOW_VCPU(r3)
/* Save R1/R2 in the PACA (64-bit) or shadow_vcpu (32-bit) */
PPC_STL r1, HSTATE_HOST_R1(r3)
PPC_STL r2, HSTATE_HOST_R2(r3)
/* Move SRR0 and SRR1 into the respective regs */
PPC_LL r9, SVCPU_PC(r3)
mtsrr0 r9
mtsrr1 r10
/* Activate guest mode, so faults get handled by KVM */
li r11, KVM_GUEST_MODE_GUEST
stb r11, HSTATE_IN_GUEST(r3)
/* Switch to guest segment. This is subarch specific. */
LOAD_GUEST_SEGMENTS
/* Enter guest */
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
PPC_LL r4, SVCPU_CTR(r3)
PPC_LL r5, SVCPU_LR(r3)
lwz r6, SVCPU_CR(r3)
lwz r7, SVCPU_XER(r3)
mtctr r4
mtlr r5
mtcr r6
mtxer r7
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
PPC_LL r0, SVCPU_R0(r3)
PPC_LL r1, SVCPU_R1(r3)
PPC_LL r2, SVCPU_R2(r3)
PPC_LL r4, SVCPU_R4(r3)
PPC_LL r5, SVCPU_R5(r3)
PPC_LL r6, SVCPU_R6(r3)
PPC_LL r7, SVCPU_R7(r3)
PPC_LL r8, SVCPU_R8(r3)
PPC_LL r9, SVCPU_R9(r3)
PPC_LL r10, SVCPU_R10(r3)
PPC_LL r11, SVCPU_R11(r3)
PPC_LL r12, SVCPU_R12(r3)
PPC_LL r13, SVCPU_R13(r3)
PPC_LL r3, (SVCPU_R3)(r3)
RFI
kvmppc_handler_trampoline_enter_end:
/******************************************************************************
* *
* Exit code *
* *
*****************************************************************************/
.global kvmppc_handler_trampoline_exit
kvmppc_handler_trampoline_exit:
.global kvmppc_interrupt
kvmppc_interrupt:
/* Register usage at this point:
*
* SPRG_SCRATCH0 = guest R13
* R12 = exit handler id
* R13 = shadow vcpu (32-bit) or PACA (64-bit)
* HSTATE.SCRATCH0 = guest R12
* HSTATE.SCRATCH1 = guest CR
*
*/
/* Save registers */
PPC_STL r0, SVCPU_R0(r13)
PPC_STL r1, SVCPU_R1(r13)
PPC_STL r2, SVCPU_R2(r13)
PPC_STL r3, SVCPU_R3(r13)
PPC_STL r4, SVCPU_R4(r13)
PPC_STL r5, SVCPU_R5(r13)
PPC_STL r6, SVCPU_R6(r13)
PPC_STL r7, SVCPU_R7(r13)
PPC_STL r8, SVCPU_R8(r13)
PPC_STL r9, SVCPU_R9(r13)
PPC_STL r10, SVCPU_R10(r13)
PPC_STL r11, SVCPU_R11(r13)
/* Restore R1/R2 so we can handle faults */
PPC_LL r1, HSTATE_HOST_R1(r13)
PPC_LL r2, HSTATE_HOST_R2(r13)
/* Save guest PC and MSR */
#ifdef CONFIG_PPC64
BEGIN_FTR_SECTION
andi. r0,r12,0x2
beq 1f
mfspr r3,SPRN_HSRR0
mfspr r4,SPRN_HSRR1
andi. r12,r12,0x3ffd
b 2f
END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
#endif
1: mfsrr0 r3
mfsrr1 r4
2:
PPC_STL r3, SVCPU_PC(r13)
PPC_STL r4, SVCPU_SHADOW_SRR1(r13)
/* Get scratch'ed off registers */
GET_SCRATCH0(r9)
PPC_LL r8, HSTATE_SCRATCH0(r13)
lwz r7, HSTATE_SCRATCH1(r13)
PPC_STL r9, SVCPU_R13(r13)
PPC_STL r8, SVCPU_R12(r13)
stw r7, SVCPU_CR(r13)
/* Save more register state */
mfxer r5
mfdar r6
mfdsisr r7
mfctr r8
mflr r9
stw r5, SVCPU_XER(r13)
PPC_STL r6, SVCPU_FAULT_DAR(r13)
stw r7, SVCPU_FAULT_DSISR(r13)
PPC_STL r8, SVCPU_CTR(r13)
PPC_STL r9, SVCPU_LR(r13)
/*
* 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
cmpwi r12, BOOK3S_INTERRUPT_ALIGNMENT
beq- ld_last_inst
b no_ld_last_inst
ld_last_inst:
/* Save off the guest instruction we're at */
/* In case lwz faults */
li r0, KVM_INST_FETCH_FAILED
#ifdef USE_QUICK_LAST_INST
/* 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, HSTATE_IN_GUEST(r13)
/* 1) enable paging for data */
mfmsr r9
ori r11, r9, MSR_DR /* Enable paging for data */
mtmsr r11
sync
/* 2) fetch the instruction */
lwz r0, 0(r3)
/* 3) disable paging again */
mtmsr r9
sync
#endif
stw r0, SVCPU_LAST_INST(r13)
no_ld_last_inst:
/* Unset guest mode */
li r9, KVM_GUEST_MODE_NONE
stb r9, HSTATE_IN_GUEST(r13)
/* Switch back to host MMU */
LOAD_HOST_SEGMENTS
/* Register usage at this point:
*
* R1 = host R1
* R2 = host R2
* R12 = exit handler id
* R13 = shadow vcpu (32-bit) or PACA (64-bit)
* SVCPU.* = guest *
*
*/
/* RFI into the highmem handler */
mfmsr r7
ori r7, r7, MSR_IR|MSR_DR|MSR_RI|MSR_ME /* Enable paging */
mtsrr1 r7
/* Load highmem handler address */
PPC_LL r8, HSTATE_VMHANDLER(r13)
mtsrr0 r8
RFI
kvmppc_handler_trampoline_exit_end: