Commit df709a29 authored by Paul Mackerras's avatar Paul Mackerras Committed by Michael Ellerman
Browse files

KVM: PPC: Book3S HV: Simplify real-mode interrupt handling 



This streamlines the first part of the code that handles a hypervisor
interrupt that occurred in the guest.  With this, all of the real-mode
handling that occurs is done before the "guest_exit_cont" label; once
we get to that label we are committed to exiting to host virtual mode.
Thus the machine check and HMI real-mode handling is moved before that
label.

Also, the code to handle external interrupts is moved out of line, as
is the code that calls kvmppc_realmode_hmi_handler().

Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
Reviewed-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 41f4e631

arch/powerpc/kvm/book3s_hv_ras.c

+8 −0
Original line number Diff line number Diff line
@@ -331,5 +331,13 @@ long kvmppc_realmode_hmi_handler(void) 
	} else {

		wait_for_tb_resync();

	}



	/*

	 * Reset tb_offset_applied so the guest exit code won't try

	 * to subtract the previous timebase offset from the timebase.

	 */

	if (local_paca->kvm_hstate.kvm_vcore)

		local_paca->kvm_hstate.kvm_vcore->tb_offset_applied = 0;



	return 0;

}

arch/powerpc/kvm/book3s_hv_rmhandlers.S

+111 −109
Original line number Diff line number Diff line
@@ -1018,8 +1018,7 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_ARCH_300) 
no_xive:

#endif /* CONFIG_KVM_XICS */



deliver_guest_interrupt:

kvmppc_cede_reentry:		/* r4 = vcpu, r13 = paca */

deliver_guest_interrupt:	/* r4 = vcpu, r13 = paca */

	/* Check if we can deliver an external or decrementer interrupt now */

	ld	r0, VCPU_PENDING_EXC(r4)

BEGIN_FTR_SECTION
@@ -1269,18 +1268,26 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) 
	std	r3, VCPU_CTR(r9)

	std	r4, VCPU_XER(r9)



#ifdef CONFIG_PPC_TRANSACTIONAL_MEM

	/* For softpatch interrupt, go off and do TM instruction emulation */

	cmpwi	r12, BOOK3S_INTERRUPT_HV_SOFTPATCH

	beq	kvmppc_tm_emul

#endif

	/* Save more register state  */

	mfdar	r3

	mfdsisr	r4

	std	r3, VCPU_DAR(r9)

	stw	r4, VCPU_DSISR(r9)



	/* If this is a page table miss then see if it's theirs or ours */

	cmpwi	r12, BOOK3S_INTERRUPT_H_DATA_STORAGE

	beq	kvmppc_hdsi

	std	r3, VCPU_FAULT_DAR(r9)

	stw	r4, VCPU_FAULT_DSISR(r9)

	cmpwi	r12, BOOK3S_INTERRUPT_H_INST_STORAGE

	beq	kvmppc_hisi



#ifdef CONFIG_PPC_TRANSACTIONAL_MEM

	/* For softpatch interrupt, go off and do TM instruction emulation */

	cmpwi	r12, BOOK3S_INTERRUPT_HV_SOFTPATCH

	beq	kvmppc_tm_emul

#endif



	/* See if this is a leftover HDEC interrupt */

	cmpwi	r12,BOOK3S_INTERRUPT_HV_DECREMENTER

	bne	2f
@@ -1303,7 +1310,7 @@ BEGIN_FTR_SECTION 
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)

	lbz	r0, HSTATE_HOST_IPI(r13)

	cmpwi	r0, 0

	beq	4f

	beq	maybe_reenter_guest

	b	guest_exit_cont

3:

	/* If it's a hypervisor facility unavailable interrupt, save HFSCR */
@@ -1315,82 +1322,16 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300) 
14:

	/* External interrupt ? */

	cmpwi	r12, BOOK3S_INTERRUPT_EXTERNAL

	bne+	guest_exit_cont



	/* External interrupt, first check for host_ipi. If this is

	 * set, we know the host wants us out so let's do it now

	 */

	bl	kvmppc_read_intr



	/*

	 * Restore the active volatile registers after returning from

	 * a C function.

	 */

	ld	r9, HSTATE_KVM_VCPU(r13)

	li	r12, BOOK3S_INTERRUPT_EXTERNAL



	/*

	 * kvmppc_read_intr return codes:

	 *

	 * Exit to host (r3 > 0)

	 *   1 An interrupt is pending that needs to be handled by the host

	 *     Exit guest and return to host by branching to guest_exit_cont

	 *

	 *   2 Passthrough that needs completion in the host

	 *     Exit guest and return to host by branching to guest_exit_cont

	 *     However, we also set r12 to BOOK3S_INTERRUPT_HV_RM_HARD

	 *     to indicate to the host to complete handling the interrupt

	 *

	 * Before returning to guest, we check if any CPU is heading out

	 * to the host and if so, we head out also. If no CPUs are heading

	 * check return values <= 0.

	 *

	 * Return to guest (r3 <= 0)

	 *  0 No external interrupt is pending

	 * -1 A guest wakeup IPI (which has now been cleared)

	 *    In either case, we return to guest to deliver any pending

	 *    guest interrupts.

	 *

	 * -2 A PCI passthrough external interrupt was handled

	 *    (interrupt was delivered directly to guest)

	 *    Return to guest to deliver any pending guest interrupts.

	 */



	cmpdi	r3, 1

	ble	1f



	/* Return code = 2 */

	li	r12, BOOK3S_INTERRUPT_HV_RM_HARD

	stw	r12, VCPU_TRAP(r9)

	b	guest_exit_cont



1:	/* Return code <= 1 */

	cmpdi	r3, 0

	bgt	guest_exit_cont



	/* Return code <= 0 */

4:	ld	r5, HSTATE_KVM_VCORE(r13)

	lwz	r0, VCORE_ENTRY_EXIT(r5)

	cmpwi	r0, 0x100

	mr	r4, r9

	blt	deliver_guest_interrupt



guest_exit_cont:		/* r9 = vcpu, r12 = trap, r13 = paca */

	/* Save more register state  */

	mfdar	r6

	mfdsisr	r7

	std	r6, VCPU_DAR(r9)

	stw	r7, VCPU_DSISR(r9)

	/* don't overwrite fault_dar/fault_dsisr if HDSI */

	cmpwi	r12,BOOK3S_INTERRUPT_H_DATA_STORAGE

	beq	mc_cont

	std	r6, VCPU_FAULT_DAR(r9)

	stw	r7, VCPU_FAULT_DSISR(r9)



	beq	kvmppc_guest_external

	/* See if it is a machine check */

	cmpwi	r12, BOOK3S_INTERRUPT_MACHINE_CHECK

	beq	machine_check_realmode

mc_cont:

	/* Or a hypervisor maintenance interrupt */

	cmpwi	r12, BOOK3S_INTERRUPT_HMI

	beq	hmi_realmode



guest_exit_cont:		/* r9 = vcpu, r12 = trap, r13 = paca */



#ifdef CONFIG_KVM_BOOK3S_HV_EXIT_TIMING

	addi	r3, r9, VCPU_TB_RMEXIT

	mr	r4, r9
@@ -1821,24 +1762,6 @@ BEGIN_FTR_SECTION 
	mtspr	SPRN_DPDES, r8

END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)



	/* If HMI, call kvmppc_realmode_hmi_handler() */

	lwz	r12, STACK_SLOT_TRAP(r1)

	cmpwi	r12, BOOK3S_INTERRUPT_HMI

	bne	27f

	bl	kvmppc_realmode_hmi_handler

	nop

	cmpdi	r3, 0

	/*

	 * At this point kvmppc_realmode_hmi_handler may have resync-ed

	 * the TB, and if it has, we must not subtract the guest timebase

	 * offset from the timebase. So, skip it.

	 *

	 * Also, do not call kvmppc_subcore_exit_guest() because it has

	 * been invoked as part of kvmppc_realmode_hmi_handler().

	 */

	beq	30f



27:

	/* Subtract timebase offset from timebase */

	ld	r8, VCORE_TB_OFFSET_APPL(r5)

	cmpdi	r8,0
@@ -1856,7 +1779,16 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) 
	addis	r8,r8,0x100		/* if so, increment upper 40 bits */

	mtspr	SPRN_TBU40,r8



17:	bl	kvmppc_subcore_exit_guest

17:

	/*

	 * If this is an HMI, we called kvmppc_realmode_hmi_handler

	 * above, which may or may not have already called

	 * kvmppc_subcore_exit_guest.  Fortunately, all that

	 * kvmppc_subcore_exit_guest does is clear a flag, so calling

	 * it again here is benign even if kvmppc_realmode_hmi_handler

	 * has already called it.

	 */

	bl	kvmppc_subcore_exit_guest

	nop

30:	ld	r5,HSTATE_KVM_VCORE(r13)

	ld	r4,VCORE_KVM(r5)	/* pointer to struct kvm */
@@ -1910,6 +1842,67 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300) 
	mtlr	r0

	blr



kvmppc_guest_external:

	/* External interrupt, first check for host_ipi. If this is

	 * set, we know the host wants us out so let's do it now

	 */

	bl	kvmppc_read_intr



	/*

	 * Restore the active volatile registers after returning from

	 * a C function.

	 */

	ld	r9, HSTATE_KVM_VCPU(r13)

	li	r12, BOOK3S_INTERRUPT_EXTERNAL



	/*

	 * kvmppc_read_intr return codes:

	 *

	 * Exit to host (r3 > 0)

	 *   1 An interrupt is pending that needs to be handled by the host

	 *     Exit guest and return to host by branching to guest_exit_cont

	 *

	 *   2 Passthrough that needs completion in the host

	 *     Exit guest and return to host by branching to guest_exit_cont

	 *     However, we also set r12 to BOOK3S_INTERRUPT_HV_RM_HARD

	 *     to indicate to the host to complete handling the interrupt

	 *

	 * Before returning to guest, we check if any CPU is heading out

	 * to the host and if so, we head out also. If no CPUs are heading

	 * check return values <= 0.

	 *

	 * Return to guest (r3 <= 0)

	 *  0 No external interrupt is pending

	 * -1 A guest wakeup IPI (which has now been cleared)

	 *    In either case, we return to guest to deliver any pending

	 *    guest interrupts.

	 *

	 * -2 A PCI passthrough external interrupt was handled

	 *    (interrupt was delivered directly to guest)

	 *    Return to guest to deliver any pending guest interrupts.

	 */



	cmpdi	r3, 1

	ble	1f



	/* Return code = 2 */

	li	r12, BOOK3S_INTERRUPT_HV_RM_HARD

	stw	r12, VCPU_TRAP(r9)

	b	guest_exit_cont



1:	/* Return code <= 1 */

	cmpdi	r3, 0

	bgt	guest_exit_cont



	/* Return code <= 0 */

maybe_reenter_guest:

	ld	r5, HSTATE_KVM_VCORE(r13)

	lwz	r0, VCORE_ENTRY_EXIT(r5)

	cmpwi	r0, 0x100

	mr	r4, r9

	blt	deliver_guest_interrupt

	b	guest_exit_cont



#ifdef CONFIG_PPC_TRANSACTIONAL_MEM

/*

 * Softpatch interrupt for transactional memory emulation cases
@@ -2685,13 +2678,7 @@ END_FTR_SECTION(CPU_FTR_TM | CPU_FTR_P9_TM_HV_ASSIST, 0) 
	mr	r9, r4

	cmpdi	r3, 0

	bgt	guest_exit_cont



	/* see if any other thread is already exiting */

	lwz	r0,VCORE_ENTRY_EXIT(r5)

	cmpwi	r0,0x100

	bge	guest_exit_cont



	b	kvmppc_cede_reentry	/* if not go back to guest */

	b	maybe_reenter_guest



	/* cede when already previously prodded case */

kvm_cede_prodded:
@@ -2758,12 +2745,12 @@ machine_check_realmode: 
	 */

	ld	r11, VCPU_MSR(r9)

	rldicl.	r0, r11, 64-MSR_HV_LG, 63 /* check if it happened in HV mode */

	bne	mc_cont			/* if so, exit to host */

	bne	guest_exit_cont		/* if so, exit to host */

	/* Check if guest is capable of handling NMI exit */

	ld	r10, VCPU_KVM(r9)

	lbz	r10, KVM_FWNMI(r10)

	cmpdi	r10, 1			/* FWNMI capable? */

	beq	mc_cont			/* if so, exit with KVM_EXIT_NMI. */

	beq	guest_exit_cont		/* if so, exit with KVM_EXIT_NMI. */



	/* if not, fall through for backward compatibility. */

	andi.	r10, r11, MSR_RI	/* check for unrecoverable exception */
@@ -2776,6 +2763,21 @@ machine_check_realmode: 
	bl	kvmppc_msr_interrupt

2:	b	fast_interrupt_c_return



/*

 * Call C code to handle a HMI in real mode.

 * Only the primary thread does the call, secondary threads are handled

 * by calling hmi_exception_realmode() after kvmppc_hv_entry returns.

 * r9 points to the vcpu on entry

 */

hmi_realmode:

	lbz	r0, HSTATE_PTID(r13)

	cmpwi	r0, 0

	bne	guest_exit_cont

	bl	kvmppc_realmode_hmi_handler

	ld	r9, HSTATE_KVM_VCPU(r13)

	li	r12, BOOK3S_INTERRUPT_HMI

	b	guest_exit_cont



/*

 * Check the reason we woke from nap, and take appropriate action.

 * Returns (in r3):

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