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linux/arch/powerpc/kvm/book3s_interrupts.S
Paul Mackerras 0214394760 KVM: PPC: book3s_pr: Simplify transitions between virtual and real mode 
This simplifies the way that the book3s_pr makes the transition to
real mode when entering the guest.  We now call kvmppc_entry_trampoline
(renamed from kvmppc_rmcall) in the base kernel using a normal function
call instead of doing an indirect call through a pointer in the vcpu.
If kvm is a module, the module loader takes care of generating a
trampoline as it does for other calls to functions outside the module.

kvmppc_entry_trampoline then disables interrupts and jumps to
kvmppc_handler_trampoline_enter in real mode using an rfi[d].
That then uses the link register as the address to return to
(potentially in module space) when the guest exits.

This also simplifies the way that we call the Linux interrupt handler
when we exit the guest due to an external, decrementer or performance
monitor interrupt.  Instead of turning on the MMU, then deciding that
we need to call the Linux handler and turning the MMU back off again,
we now go straight to the handler at the point where we would turn the
MMU on.  The handler will then return to the virtual-mode code
(potentially in the module).

Along the way, this moves the setting and clearing of the HID5 DCBZ32
bit into real-mode interrupts-off code, and also makes sure that
we clear the MSR[RI] bit before loading values into SRR0/1.

The net result is that we no longer need any code addresses to be
stored in vcpu->arch.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
2011-09-25 19:52:29 +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)
#elif defined(CONFIG_PPC_BOOK3S_32)
#define ULONG_SIZE 4
#define FUNC(name) name
#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:
#ifdef CONFIG_PPC_BOOK3S_64
PPC_LL r3, VCPU_HFLAGS(r4)
rldicl r3, r3, 0, 63 /* r3 &= 1 */
stb r3, HSTATE_RESTORE_HID5(r13)
#endif /* CONFIG_PPC_BOOK3S_64 */
PPC_LL r4, VCPU_SHADOW_MSR(r4) /* get shadow_msr */
/* Jump to segment patching handler and into our guest */
bl FUNC(kvmppc_entry_trampoline)
nop
/*
* 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)
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)
/* 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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