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alistair23-linux/arch/powerpc/kvm/book3s_interrupts.S
Paul Mackerras 3c42bf8a71 KVM: PPC: Split host-state fields out of kvmppc_book3s_shadow_vcpu 
There are several fields in struct kvmppc_book3s_shadow_vcpu that
temporarily store bits of host state while a guest is running,
rather than anything relating to the particular guest or vcpu.
This splits them out into a new kvmppc_host_state structure and
modifies the definitions in asm-offsets.c to suit.

On 32-bit, we have a kvmppc_host_state structure inside the
kvmppc_book3s_shadow_vcpu since the assembly code needs to be able
to get to them both with one pointer.  On 64-bit they are separate
fields in the PACA.  This means that on 64-bit we don't need to
copy the kvmppc_host_state in and out on vcpu load/unload, and
in future will mean that the book3s_hv code doesn't need a
shadow_vcpu struct in the PACA at all.  That does mean that we
have to be careful not to rely on any values persisting in the
hstate field of the paca across any point where we could block
or get preempted.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-12 13:16:53 +03:00

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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 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>
#if defined(CONFIG_PPC_BOOK3S_64)
#define ULONG_SIZE 8
#define FUNC(name) GLUE(.,name)
#define GET_SHADOW_VCPU_R13
#define DISABLE_INTERRUPTS \
mfmsr r0; \
rldicl r0,r0,48,1; \
rotldi r0,r0,16; \
mtmsrd r0,1; \
#elif defined(CONFIG_PPC_BOOK3S_32)
#define ULONG_SIZE 4
#define FUNC(name) name
#define GET_SHADOW_VCPU_R13 \
lwz r13, (THREAD + THREAD_KVM_SVCPU)(r2)
#define DISABLE_INTERRUPTS \
mfmsr r0; \
rlwinm r0,r0,0,17,15; \
mtmsr r0; \
#endif /* CONFIG_PPC_BOOK3S_XX */
#define VCPU_GPR(n) (VCPU_GPRS + (n * ULONG_SIZE))
#define VCPU_LOAD_NVGPRS(vcpu) \
PPC_LL r14, VCPU_GPR(r14)(vcpu); \
PPC_LL r15, VCPU_GPR(r15)(vcpu); \
PPC_LL r16, VCPU_GPR(r16)(vcpu); \
PPC_LL r17, VCPU_GPR(r17)(vcpu); \
PPC_LL r18, VCPU_GPR(r18)(vcpu); \
PPC_LL r19, VCPU_GPR(r19)(vcpu); \
PPC_LL r20, VCPU_GPR(r20)(vcpu); \
PPC_LL r21, VCPU_GPR(r21)(vcpu); \
PPC_LL r22, VCPU_GPR(r22)(vcpu); \
PPC_LL r23, VCPU_GPR(r23)(vcpu); \
PPC_LL r24, VCPU_GPR(r24)(vcpu); \
PPC_LL r25, VCPU_GPR(r25)(vcpu); \
PPC_LL r26, VCPU_GPR(r26)(vcpu); \
PPC_LL r27, VCPU_GPR(r27)(vcpu); \
PPC_LL r28, VCPU_GPR(r28)(vcpu); \
PPC_LL r29, VCPU_GPR(r29)(vcpu); \
PPC_LL r30, VCPU_GPR(r30)(vcpu); \
PPC_LL r31, VCPU_GPR(r31)(vcpu); \
/*****************************************************************************
* *
* Guest entry / exit code that is in kernel module memory (highmem) *
* *
****************************************************************************/
/* Registers:
* r3: kvm_run pointer
* r4: vcpu pointer
*/
_GLOBAL(__kvmppc_vcpu_run)
kvm_start_entry:
/* Write correct stack frame */
mflr r0
PPC_STL r0,PPC_LR_STKOFF(r1)
/* Save host state to the stack */
PPC_STLU r1, -SWITCH_FRAME_SIZE(r1)
/* Save r3 (kvm_run) and r4 (vcpu) */
SAVE_2GPRS(3, r1)
/* Save non-volatile registers (r14 - r31) */
SAVE_NVGPRS(r1)
/* Save LR */
PPC_STL r0, _LINK(r1)
/* Load non-volatile guest state from the vcpu */
VCPU_LOAD_NVGPRS(r4)
kvm_start_lightweight:
GET_SHADOW_VCPU_R13
PPC_LL r3, VCPU_HIGHMEM_HANDLER(r4)
PPC_STL r3, HSTATE_VMHANDLER(r13)
PPC_LL r10, VCPU_SHADOW_MSR(r4) /* r10 = vcpu->arch.shadow_msr */
DISABLE_INTERRUPTS
#ifdef CONFIG_PPC_BOOK3S_64
/* Some guests may need to have dcbz set to 32 byte length.
*
* Usually we ensure that by patching the guest's instructions
* to trap on dcbz and emulate it in the hypervisor.
*
* If we can, we should tell the CPU to use 32 byte dcbz though,
* because that's a lot faster.
*/
PPC_LL r3, VCPU_HFLAGS(r4)
rldicl. r3, r3, 0, 63 /* CR = ((r3 & 1) == 0) */
beq no_dcbz32_on
mfspr r3,SPRN_HID5
ori r3, r3, 0x80 /* XXX HID5_dcbz32 = 0x80 */
mtspr SPRN_HID5,r3
no_dcbz32_on:
#endif /* CONFIG_PPC_BOOK3S_64 */
PPC_LL r6, VCPU_RMCALL(r4)
mtctr r6
PPC_LL r3, VCPU_TRAMPOLINE_ENTER(r4)
LOAD_REG_IMMEDIATE(r4, MSR_KERNEL & ~(MSR_IR | MSR_DR))
/* Jump to segment patching handler and into our guest */
bctr
/*
* This is the handler in module memory. It gets jumped at from the
* lowmem trampoline code, so it's basically the guest exit code.
*
*/
.global kvmppc_handler_highmem
kvmppc_handler_highmem:
/*
* Register usage at this point:
*
* R1 = host R1
* R2 = host R2
* R12 = exit handler id
* R13 = PACA
* SVCPU.* = guest *
*
*/
/* R7 = vcpu */
PPC_LL r7, GPR4(r1)
#ifdef CONFIG_PPC_BOOK3S_64
PPC_LL r5, VCPU_HFLAGS(r7)
rldicl. r5, r5, 0, 63 /* CR = ((r5 & 1) == 0) */
beq no_dcbz32_off
li r4, 0
mfspr r5,SPRN_HID5
rldimi r5,r4,6,56
mtspr SPRN_HID5,r5
no_dcbz32_off:
#endif /* CONFIG_PPC_BOOK3S_64 */
PPC_STL r14, VCPU_GPR(r14)(r7)
PPC_STL r15, VCPU_GPR(r15)(r7)
PPC_STL r16, VCPU_GPR(r16)(r7)
PPC_STL r17, VCPU_GPR(r17)(r7)
PPC_STL r18, VCPU_GPR(r18)(r7)
PPC_STL r19, VCPU_GPR(r19)(r7)
PPC_STL r20, VCPU_GPR(r20)(r7)
PPC_STL r21, VCPU_GPR(r21)(r7)
PPC_STL r22, VCPU_GPR(r22)(r7)
PPC_STL r23, VCPU_GPR(r23)(r7)
PPC_STL r24, VCPU_GPR(r24)(r7)
PPC_STL r25, VCPU_GPR(r25)(r7)
PPC_STL r26, VCPU_GPR(r26)(r7)
PPC_STL r27, VCPU_GPR(r27)(r7)
PPC_STL r28, VCPU_GPR(r28)(r7)
PPC_STL r29, VCPU_GPR(r29)(r7)
PPC_STL r30, VCPU_GPR(r30)(r7)
PPC_STL r31, VCPU_GPR(r31)(r7)
/* Restore host msr -> SRR1 */
PPC_LL r6, VCPU_HOST_MSR(r7)
/*
* For some interrupts, we need to call the real Linux
* handler, so it can do work for us. This has to happen
* as if the interrupt arrived from the kernel though,
* so let's fake it here where most state is restored.
*
* Call Linux for hardware interrupts/decrementer
* r3 = address of interrupt handler (exit reason)
*/
cmpwi r12, BOOK3S_INTERRUPT_EXTERNAL
beq call_linux_handler
cmpwi r12, BOOK3S_INTERRUPT_DECREMENTER
beq call_linux_handler
cmpwi r12, BOOK3S_INTERRUPT_PERFMON
beq call_linux_handler
/* Back to EE=1 */
mtmsr r6
sync
b kvm_return_point
call_linux_handler:
/*
* If we land here we need to jump back to the handler we
* came from.
*
* We have a page that we can access from real mode, so let's
* jump back to that and use it as a trampoline to get back into the
* interrupt handler!
*
* R3 still contains the exit code,
* R5 VCPU_HOST_RETIP and
* R6 VCPU_HOST_MSR
*/
/* Restore host IP -> SRR0 */
PPC_LL r5, VCPU_HOST_RETIP(r7)
/* XXX Better move to a safe function?
* What if we get an HTAB flush in between mtsrr0 and mtsrr1? */
mtlr r12
PPC_LL r4, VCPU_TRAMPOLINE_LOWMEM(r7)
mtsrr0 r4
LOAD_REG_IMMEDIATE(r3, MSR_KERNEL & ~(MSR_IR | MSR_DR))
mtsrr1 r3
RFI
.global kvm_return_point
kvm_return_point:
/* Jump back to lightweight entry if we're supposed to */
/* go back into the guest */
/* Pass the exit number as 3rd argument to kvmppc_handle_exit */
mr r5, r12
/* Restore r3 (kvm_run) and r4 (vcpu) */
REST_2GPRS(3, r1)
bl FUNC(kvmppc_handle_exit)
/* If RESUME_GUEST, get back in the loop */
cmpwi r3, RESUME_GUEST
beq kvm_loop_lightweight
cmpwi r3, RESUME_GUEST_NV
beq kvm_loop_heavyweight
kvm_exit_loop:
PPC_LL r4, _LINK(r1)
mtlr r4
/* Restore non-volatile host registers (r14 - r31) */
REST_NVGPRS(r1)
addi r1, r1, SWITCH_FRAME_SIZE
blr
kvm_loop_heavyweight:
PPC_LL r4, _LINK(r1)
PPC_STL r4, (PPC_LR_STKOFF + SWITCH_FRAME_SIZE)(r1)
/* Load vcpu and cpu_run */
REST_2GPRS(3, r1)
/* Load non-volatile guest state from the vcpu */
VCPU_LOAD_NVGPRS(r4)
/* Jump back into the beginning of this function */
b kvm_start_lightweight
kvm_loop_lightweight:
/* We'll need the vcpu pointer */
REST_GPR(4, r1)
/* Jump back into the beginning of this function */
b kvm_start_lightweight
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