Commit 218309b7 authored by Paul Mackerras's avatar Paul Mackerras Committed by Alexander Graf
Browse files

KVM: PPC: Book3S HV: Restructure kvmppc_hv_entry to be a subroutine 



We have two paths into and out of the low-level guest entry and exit
code: from a vcpu task via kvmppc_hv_entry_trampoline, and from the
system reset vector for an offline secondary thread on POWER7 via
kvm_start_guest.  Currently both just branch to kvmppc_hv_entry to
enter the guest, and on guest exit, we test the vcpu physical thread
ID to detect which way we came in and thus whether we should return
to the vcpu task or go back to nap mode.

In order to make the code flow clearer, and to keep the code relating
to each flow together, this turns kvmppc_hv_entry into a subroutine
that follows the normal conventions for call and return.  This means
that kvmppc_hv_entry_trampoline() and kvmppc_hv_entry() now establish
normal stack frames, and we use the normal stack slots for saving
return addresses rather than local_paca->kvm_hstate.vmhandler.  Apart
from that this is mostly moving code around unchanged.

Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
parent 42d7604d

arch/powerpc/kvm/book3s_hv_rmhandlers.S

+178 −166
Original line number Diff line number Diff line
@@ -66,8 +66,11 @@ kvmppc_skip_Hinterrupt: 
 * LR = return address to continue at after eventually re-enabling MMU

 */

_GLOBAL(kvmppc_hv_entry_trampoline)

	mflr	r0

	std	r0, PPC_LR_STKOFF(r1)

	stdu	r1, -112(r1)

	mfmsr	r10

	LOAD_REG_ADDR(r5, kvmppc_hv_entry)

	LOAD_REG_ADDR(r5, kvmppc_call_hv_entry)

	li	r0,MSR_RI

	andc	r0,r10,r0

	li	r6,MSR_IR | MSR_DR
@@ -77,11 +80,103 @@ _GLOBAL(kvmppc_hv_entry_trampoline) 
	mtsrr1	r6

	RFI



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

 *                                                                            *

 *                               Entry code                                   *

 *                                                                            *

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

kvmppc_call_hv_entry:

	bl	kvmppc_hv_entry



	/* Back from guest - restore host state and return to caller */



	/* Restore host DABR and DABRX */

	ld	r5,HSTATE_DABR(r13)

	li	r6,7

	mtspr	SPRN_DABR,r5

	mtspr	SPRN_DABRX,r6



	/* Restore SPRG3 */

	ld	r3,PACA_SPRG3(r13)

	mtspr	SPRN_SPRG3,r3



	/*

	 * Reload DEC.  HDEC interrupts were disabled when

	 * we reloaded the host's LPCR value.

	 */

	ld	r3, HSTATE_DECEXP(r13)

	mftb	r4

	subf	r4, r4, r3

	mtspr	SPRN_DEC, r4



	/* Reload the host's PMU registers */

	ld	r3, PACALPPACAPTR(r13)	/* is the host using the PMU? */

	lbz	r4, LPPACA_PMCINUSE(r3)

	cmpwi	r4, 0

	beq	23f			/* skip if not */

	lwz	r3, HSTATE_PMC(r13)

	lwz	r4, HSTATE_PMC + 4(r13)

	lwz	r5, HSTATE_PMC + 8(r13)

	lwz	r6, HSTATE_PMC + 12(r13)

	lwz	r8, HSTATE_PMC + 16(r13)

	lwz	r9, HSTATE_PMC + 20(r13)

BEGIN_FTR_SECTION

	lwz	r10, HSTATE_PMC + 24(r13)

	lwz	r11, HSTATE_PMC + 28(r13)

END_FTR_SECTION_IFSET(CPU_FTR_ARCH_201)

	mtspr	SPRN_PMC1, r3

	mtspr	SPRN_PMC2, r4

	mtspr	SPRN_PMC3, r5

	mtspr	SPRN_PMC4, r6

	mtspr	SPRN_PMC5, r8

	mtspr	SPRN_PMC6, r9

BEGIN_FTR_SECTION

	mtspr	SPRN_PMC7, r10

	mtspr	SPRN_PMC8, r11

END_FTR_SECTION_IFSET(CPU_FTR_ARCH_201)

	ld	r3, HSTATE_MMCR(r13)

	ld	r4, HSTATE_MMCR + 8(r13)

	ld	r5, HSTATE_MMCR + 16(r13)

	mtspr	SPRN_MMCR1, r4

	mtspr	SPRN_MMCRA, r5

	mtspr	SPRN_MMCR0, r3

	isync

23:



	/*

	 * For external and machine check interrupts, we need

	 * to call the Linux handler to process the interrupt.

	 * We do that by jumping to absolute address 0x500 for

	 * external interrupts, or the machine_check_fwnmi label

	 * for machine checks (since firmware might have patched

	 * the vector area at 0x200).  The [h]rfid at the end of the

	 * handler will return to the book3s_hv_interrupts.S code.

	 * For other interrupts we do the rfid to get back

	 * to the book3s_hv_interrupts.S code here.

	 */

	ld	r8, 112+PPC_LR_STKOFF(r1)

	addi	r1, r1, 112

	ld	r7, HSTATE_HOST_MSR(r13)



	cmpwi	cr1, r12, BOOK3S_INTERRUPT_MACHINE_CHECK

	cmpwi	r12, BOOK3S_INTERRUPT_EXTERNAL

BEGIN_FTR_SECTION

	beq	11f

END_FTR_SECTION_IFSET(CPU_FTR_ARCH_206)



	/* RFI into the highmem handler, or branch to interrupt handler */

	mfmsr	r6

	li	r0, MSR_RI

	andc	r6, r6, r0

	mtmsrd	r6, 1			/* Clear RI in MSR */

	mtsrr0	r8

	mtsrr1	r7

	beqa	0x500			/* external interrupt (PPC970) */

	beq	cr1, 13f		/* machine check */

	RFI



	/* On POWER7, we have external interrupts set to use HSRR0/1 */

11:	mtspr	SPRN_HSRR0, r8

	mtspr	SPRN_HSRR1, r7

	ba	0x500



13:	b	machine_check_fwnmi





/*

 * We come in here when wakened from nap mode on a secondary hw thread.
@@ -137,7 +232,7 @@ kvm_start_guest: 
	cmpdi	r4,0

	/* if we have no vcpu to run, go back to sleep */

	beq	kvm_no_guest

	b	kvmppc_hv_entry

	b	30f



27:	/* XXX should handle hypervisor maintenance interrupts etc. here */

	b	kvm_no_guest
@@ -147,6 +242,57 @@ kvm_start_guest: 
	stw	r8,HSTATE_SAVED_XIRR(r13)

	b	kvm_no_guest



30:	bl	kvmppc_hv_entry



	/* Back from the guest, go back to nap */

	/* Clear our vcpu pointer so we don't come back in early */

	li	r0, 0

	std	r0, HSTATE_KVM_VCPU(r13)

	lwsync

	/* Clear any pending IPI - we're an offline thread */

	ld	r5, HSTATE_XICS_PHYS(r13)

	li	r7, XICS_XIRR

	lwzcix	r3, r5, r7		/* ack any pending interrupt */

	rlwinm.	r0, r3, 0, 0xffffff	/* any pending? */

	beq	37f

	sync

	li	r0, 0xff

	li	r6, XICS_MFRR

	stbcix	r0, r5, r6		/* clear the IPI */

	stwcix	r3, r5, r7		/* EOI it */

37:	sync



	/* increment the nap count and then go to nap mode */

	ld	r4, HSTATE_KVM_VCORE(r13)

	addi	r4, r4, VCORE_NAP_COUNT

	lwsync				/* make previous updates visible */

51:	lwarx	r3, 0, r4

	addi	r3, r3, 1

	stwcx.	r3, 0, r4

	bne	51b



kvm_no_guest:

	li	r0, KVM_HWTHREAD_IN_NAP

	stb	r0, HSTATE_HWTHREAD_STATE(r13)

	li	r3, LPCR_PECE0

	mfspr	r4, SPRN_LPCR

	rlwimi	r4, r3, 0, LPCR_PECE0 | LPCR_PECE1

	mtspr	SPRN_LPCR, r4

	isync

	std	r0, HSTATE_SCRATCH0(r13)

	ptesync

	ld	r0, HSTATE_SCRATCH0(r13)

1:	cmpd	r0, r0

	bne	1b

	nap

	b	.



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

 *                                                                            *

 *                               Entry code                                   *

 *                                                                            *

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



.global kvmppc_hv_entry

kvmppc_hv_entry:
@@ -159,7 +305,8 @@ kvmppc_hv_entry: 
	 * all other volatile GPRS = free

	 */

	mflr	r0

	std	r0, HSTATE_VMHANDLER(r13)

	std	r0, PPC_LR_STKOFF(r1)

	stdu	r1, -112(r1)



	/* Set partition DABR */

	/* Do this before re-enabling PMU to avoid P7 DABR corruption bug */
@@ -1198,103 +1345,30 @@ BEGIN_FTR_SECTION 
	stw	r11, VCPU_PMC + 28(r9)

END_FTR_SECTION_IFSET(CPU_FTR_ARCH_201)

22:

	ld	r0, 112+PPC_LR_STKOFF(r1)

	addi	r1, r1, 112

	mtlr	r0

	blr

secondary_too_late:

	ld	r5,HSTATE_KVM_VCORE(r13)

	HMT_LOW

13:	lbz	r3,VCORE_IN_GUEST(r5)

	cmpwi	r3,0

	bne	13b

	HMT_MEDIUM

	li	r0, KVM_GUEST_MODE_NONE

	stb	r0, HSTATE_IN_GUEST(r13)

	ld	r11,PACA_SLBSHADOWPTR(r13)



	/* Secondary threads go off to take a nap on POWER7 */

BEGIN_FTR_SECTION

	lwz	r0,VCPU_PTID(r9)

	cmpwi	r0,0

	bne	secondary_nap

END_FTR_SECTION_IFSET(CPU_FTR_ARCH_206)



	/* Restore host DABR and DABRX */

	ld	r5,HSTATE_DABR(r13)

	li	r6,7

	mtspr	SPRN_DABR,r5

	mtspr	SPRN_DABRX,r6



	/* Restore SPRG3 */

	ld	r3,PACA_SPRG3(r13)

	mtspr	SPRN_SPRG3,r3



	/*

	 * Reload DEC.  HDEC interrupts were disabled when

	 * we reloaded the host's LPCR value.

	 */

	ld	r3, HSTATE_DECEXP(r13)

	mftb	r4

	subf	r4, r4, r3

	mtspr	SPRN_DEC, r4



	/* Reload the host's PMU registers */

	ld	r3, PACALPPACAPTR(r13)	/* is the host using the PMU? */

	lbz	r4, LPPACA_PMCINUSE(r3)

	cmpwi	r4, 0

	beq	23f			/* skip if not */

	lwz	r3, HSTATE_PMC(r13)

	lwz	r4, HSTATE_PMC + 4(r13)

	lwz	r5, HSTATE_PMC + 8(r13)

	lwz	r6, HSTATE_PMC + 12(r13)

	lwz	r8, HSTATE_PMC + 16(r13)

	lwz	r9, HSTATE_PMC + 20(r13)

BEGIN_FTR_SECTION

	lwz	r10, HSTATE_PMC + 24(r13)

	lwz	r11, HSTATE_PMC + 28(r13)

END_FTR_SECTION_IFSET(CPU_FTR_ARCH_201)

	mtspr	SPRN_PMC1, r3

	mtspr	SPRN_PMC2, r4

	mtspr	SPRN_PMC3, r5

	mtspr	SPRN_PMC4, r6

	mtspr	SPRN_PMC5, r8

	mtspr	SPRN_PMC6, r9

BEGIN_FTR_SECTION

	mtspr	SPRN_PMC7, r10

	mtspr	SPRN_PMC8, r11

END_FTR_SECTION_IFSET(CPU_FTR_ARCH_201)

	ld	r3, HSTATE_MMCR(r13)

	ld	r4, HSTATE_MMCR + 8(r13)

	ld	r5, HSTATE_MMCR + 16(r13)

	mtspr	SPRN_MMCR1, r4

	mtspr	SPRN_MMCRA, r5

	mtspr	SPRN_MMCR0, r3

	isync

23:

	/*

	 * For external and machine check interrupts, we need

	 * to call the Linux handler to process the interrupt.

	 * We do that by jumping to absolute address 0x500 for

	 * external interrupts, or the machine_check_fwnmi label

	 * for machine checks (since firmware might have patched

	 * the vector area at 0x200).  The [h]rfid at the end of the

	 * handler will return to the book3s_hv_interrupts.S code.

	 * For other interrupts we do the rfid to get back

	 * to the book3s_hv_interrupts.S code here.

	 */

	ld	r8, HSTATE_VMHANDLER(r13)

	ld	r7, HSTATE_HOST_MSR(r13)



	cmpwi	cr1, r12, BOOK3S_INTERRUPT_MACHINE_CHECK

	cmpwi	r12, BOOK3S_INTERRUPT_EXTERNAL

BEGIN_FTR_SECTION

	beq	11f

END_FTR_SECTION_IFSET(CPU_FTR_ARCH_206)



	/* RFI into the highmem handler, or branch to interrupt handler */

	mfmsr	r6

	li	r0, MSR_RI

	andc	r6, r6, r0

	mtmsrd	r6, 1			/* Clear RI in MSR */

	mtsrr0	r8

	mtsrr1	r7

	beqa	0x500			/* external interrupt (PPC970) */

	beq	cr1, 13f		/* machine check */

	RFI



	/* On POWER7, we have external interrupts set to use HSRR0/1 */

11:	mtspr	SPRN_HSRR0, r8

	mtspr	SPRN_HSRR1, r7

	ba	0x500



13:	b	machine_check_fwnmi

	.rept	SLB_NUM_BOLTED

	ld	r5,SLBSHADOW_SAVEAREA(r11)

	ld	r6,SLBSHADOW_SAVEAREA+8(r11)

	andis.	r7,r5,SLB_ESID_V@h

	beq	1f

	slbmte	r6,r5

1:	addi	r11,r11,16

	.endr

	b	22b



/*

 * Check whether an HDSI is an HPTE not found fault or something else.
@@ -1741,68 +1815,6 @@ machine_check_realmode: 
	rotldi	r11, r11, 63

	b	fast_interrupt_c_return



secondary_too_late:

	ld	r5,HSTATE_KVM_VCORE(r13)

	HMT_LOW

13:	lbz	r3,VCORE_IN_GUEST(r5)

	cmpwi	r3,0

	bne	13b

	HMT_MEDIUM

	ld	r11,PACA_SLBSHADOWPTR(r13)



	.rept	SLB_NUM_BOLTED

	ld	r5,SLBSHADOW_SAVEAREA(r11)

	ld	r6,SLBSHADOW_SAVEAREA+8(r11)

	andis.	r7,r5,SLB_ESID_V@h

	beq	1f

	slbmte	r6,r5

1:	addi	r11,r11,16

	.endr



secondary_nap:

	/* Clear our vcpu pointer so we don't come back in early */

	li	r0, 0

	std	r0, HSTATE_KVM_VCPU(r13)

	lwsync

	/* Clear any pending IPI - assume we're a secondary thread */

	ld	r5, HSTATE_XICS_PHYS(r13)

	li	r7, XICS_XIRR

	lwzcix	r3, r5, r7		/* ack any pending interrupt */

	rlwinm.	r0, r3, 0, 0xffffff	/* any pending? */

	beq	37f

	sync

	li	r0, 0xff

	li	r6, XICS_MFRR

	stbcix	r0, r5, r6		/* clear the IPI */

	stwcix	r3, r5, r7		/* EOI it */

37:	sync



	/* increment the nap count and then go to nap mode */

	ld	r4, HSTATE_KVM_VCORE(r13)

	addi	r4, r4, VCORE_NAP_COUNT

	lwsync				/* make previous updates visible */

51:	lwarx	r3, 0, r4

	addi	r3, r3, 1

	stwcx.	r3, 0, r4

	bne	51b



kvm_no_guest:

	li	r0, KVM_HWTHREAD_IN_NAP

	stb	r0, HSTATE_HWTHREAD_STATE(r13)



	li	r3, LPCR_PECE0

	mfspr	r4, SPRN_LPCR

	rlwimi	r4, r3, 0, LPCR_PECE0 | LPCR_PECE1

	mtspr	SPRN_LPCR, r4

	isync

	std	r0, HSTATE_SCRATCH0(r13)

	ptesync

	ld	r0, HSTATE_SCRATCH0(r13)

1:	cmpd	r0, r0

	bne	1b

	nap

	b	.



/*

 * Save away FP, VMX and VSX registers.

 * r3 = vcpu pointer

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