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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/powerpc/kvm/book3s_rmhandlers.S
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/* SPDX-License-Identifier: GPL-2.0-only */

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/*

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 *

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 * Copyright SUSE Linux Products GmbH 2009

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 *

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 * Authors: Alexander Graf <[email protected]>

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 */

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#include <asm/ppc_asm.h>

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#include <asm/kvm_asm.h>

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#include <asm/reg.h>

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#include <asm/mmu.h>

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#include <asm/page.h>

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#include <asm/asm-offsets.h>

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#include <asm/asm-compat.h>

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#ifdef CONFIG_PPC_BOOK3S_64

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#include <asm/exception-64s.h>

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#endif

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/*****************************************************************************

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 *                                                                           *

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 *        Real Mode handlers that need to be in low physical memory          *

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 *                                                                           *

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 ****************************************************************************/

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#if defined(CONFIG_PPC_BOOK3S_64)

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#ifdef CONFIG_PPC64_ELF_ABI_V2

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#define FUNC(name) 		name

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#else

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#define FUNC(name) 		GLUE(.,name)

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#endif

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#elif defined(CONFIG_PPC_BOOK3S_32)

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#define FUNC(name)		name

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#define RFI_TO_KERNEL	rfi

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#define RFI_TO_GUEST	rfi

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.macro INTERRUPT_TRAMPOLINE intno

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.global kvmppc_trampoline_\intno

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kvmppc_trampoline_\intno:

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	mtspr	SPRN_SPRG_SCRATCH0, r13		/* Save r13 */

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	/*

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	 * First thing to do is to find out if we're coming

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	 * from a KVM guest or a Linux process.

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	 *

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	 * To distinguish, we check a magic byte in the PACA/current

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	 */

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	mfspr	r13, SPRN_SPRG_THREAD

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	lwz	r13, THREAD_KVM_SVCPU(r13)

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	/* PPC32 can have a NULL pointer - let's check for that */

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	mtspr   SPRN_SPRG_SCRATCH1, r12		/* Save r12 */

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	mfcr	r12

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	cmpwi	r13, 0

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	bne	1f

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2:	mtcr	r12

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	mfspr	r12, SPRN_SPRG_SCRATCH1

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	mfspr	r13, SPRN_SPRG_SCRATCH0		/* r13 = original r13 */

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	b	kvmppc_resume_\intno		/* Get back original handler */

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1:	tophys(r13, r13)

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	stw	r12, HSTATE_SCRATCH1(r13)

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	mfspr	r12, SPRN_SPRG_SCRATCH1

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	stw	r12, HSTATE_SCRATCH0(r13)

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	lbz	r12, HSTATE_IN_GUEST(r13)

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	cmpwi	r12, KVM_GUEST_MODE_NONE

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	bne	..kvmppc_handler_hasmagic_\intno

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	/* No KVM guest? Then jump back to the Linux handler! */

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	lwz	r12, HSTATE_SCRATCH1(r13)

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	b	2b

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	/* Now we know we're handling a KVM guest */

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..kvmppc_handler_hasmagic_\intno:

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	/* Should we just skip the faulting instruction? */

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	cmpwi	r12, KVM_GUEST_MODE_SKIP

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	beq	kvmppc_handler_skip_ins

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	/* Let's store which interrupt we're handling */

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	li	r12, \intno

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	/* Jump into the SLB exit code that goes to the highmem handler */

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	b	kvmppc_handler_trampoline_exit

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.endm

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INTERRUPT_TRAMPOLINE	BOOK3S_INTERRUPT_SYSTEM_RESET

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INTERRUPT_TRAMPOLINE	BOOK3S_INTERRUPT_MACHINE_CHECK

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INTERRUPT_TRAMPOLINE	BOOK3S_INTERRUPT_DATA_STORAGE

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INTERRUPT_TRAMPOLINE	BOOK3S_INTERRUPT_INST_STORAGE

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INTERRUPT_TRAMPOLINE	BOOK3S_INTERRUPT_EXTERNAL

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INTERRUPT_TRAMPOLINE	BOOK3S_INTERRUPT_ALIGNMENT

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INTERRUPT_TRAMPOLINE	BOOK3S_INTERRUPT_PROGRAM

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INTERRUPT_TRAMPOLINE	BOOK3S_INTERRUPT_FP_UNAVAIL

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INTERRUPT_TRAMPOLINE	BOOK3S_INTERRUPT_DECREMENTER

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INTERRUPT_TRAMPOLINE	BOOK3S_INTERRUPT_SYSCALL

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INTERRUPT_TRAMPOLINE	BOOK3S_INTERRUPT_TRACE

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INTERRUPT_TRAMPOLINE	BOOK3S_INTERRUPT_PERFMON

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INTERRUPT_TRAMPOLINE	BOOK3S_INTERRUPT_ALTIVEC

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/*

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 * Bring us back to the faulting code, but skip the

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 * faulting instruction.

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 *

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 * This is a generic exit path from the interrupt

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 * trampolines above.

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 *

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 * Input Registers:

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 *

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 * R12            = free

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 * R13            = Shadow VCPU (PACA)

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 * HSTATE.SCRATCH0 = guest R12

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 * HSTATE.SCRATCH1 = guest CR

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 * SPRG_SCRATCH0  = guest R13

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 *

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 */

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kvmppc_handler_skip_ins:

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	/* Patch the IP to the next instruction */

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	/* Note that prefixed instructions are disabled in PR KVM for now */

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	mfsrr0	r12

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	addi	r12, r12, 4

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	mtsrr0	r12

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	/* Clean up all state */

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	lwz	r12, HSTATE_SCRATCH1(r13)

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	mtcr	r12

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	PPC_LL	r12, HSTATE_SCRATCH0(r13)

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	GET_SCRATCH0(r13)

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	/* And get back into the code */

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	RFI_TO_KERNEL

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#endif

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/*

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 * Call kvmppc_handler_trampoline_enter in real mode

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 *

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 * On entry, r4 contains the guest shadow MSR

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 * MSR.EE has to be 0 when calling this function

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 */

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_GLOBAL_TOC(kvmppc_entry_trampoline)

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	mfmsr	r5

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	LOAD_REG_ADDR(r7, kvmppc_handler_trampoline_enter)

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	toreal(r7)

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	li	r6, MSR_IR | MSR_DR

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	andc	r6, r5, r6	/* Clear DR and IR in MSR value */

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	/*

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	 * Set EE in HOST_MSR so that it's enabled when we get into our

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	 * C exit handler function.

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	 */

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	ori	r5, r5, MSR_EE

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	mtsrr0	r7

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	mtsrr1	r6

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	RFI_TO_KERNEL

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#include "book3s_segment.S"

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