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: Paul Mackerras <paulus@ozlabs.org> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Paul Mackerras
Michael Ellerman
parent
41f4e631da
commit
df709a296e
@ -331,5 +331,13 @@ long kvmppc_realmode_hmi_handler(void)
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} else {
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wait_for_tb_resync();
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}
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/*
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* Reset tb_offset_applied so the guest exit code won't try
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* to subtract the previous timebase offset from the timebase.
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*/
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if (local_paca->kvm_hstate.kvm_vcore)
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local_paca->kvm_hstate.kvm_vcore->tb_offset_applied = 0;
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return 0;
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}
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@ -1018,8 +1018,7 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_ARCH_300)
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no_xive:
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#endif /* CONFIG_KVM_XICS */
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deliver_guest_interrupt:
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kvmppc_cede_reentry: /* r4 = vcpu, r13 = paca */
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deliver_guest_interrupt: /* r4 = vcpu, r13 = paca */
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/* Check if we can deliver an external or decrementer interrupt now */
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ld r0, VCPU_PENDING_EXC(r4)
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BEGIN_FTR_SECTION
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@ -1269,18 +1268,26 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
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std r3, VCPU_CTR(r9)
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std r4, VCPU_XER(r9)
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/* Save more register state */
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mfdar r3
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mfdsisr r4
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std r3, VCPU_DAR(r9)
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stw r4, VCPU_DSISR(r9)
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/* If this is a page table miss then see if it's theirs or ours */
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cmpwi r12, BOOK3S_INTERRUPT_H_DATA_STORAGE
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beq kvmppc_hdsi
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std r3, VCPU_FAULT_DAR(r9)
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stw r4, VCPU_FAULT_DSISR(r9)
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cmpwi r12, BOOK3S_INTERRUPT_H_INST_STORAGE
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beq kvmppc_hisi
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#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
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/* For softpatch interrupt, go off and do TM instruction emulation */
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cmpwi r12, BOOK3S_INTERRUPT_HV_SOFTPATCH
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beq kvmppc_tm_emul
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#endif
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/* If this is a page table miss then see if it's theirs or ours */
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cmpwi r12, BOOK3S_INTERRUPT_H_DATA_STORAGE
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beq kvmppc_hdsi
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cmpwi r12, BOOK3S_INTERRUPT_H_INST_STORAGE
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beq kvmppc_hisi
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/* See if this is a leftover HDEC interrupt */
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cmpwi r12,BOOK3S_INTERRUPT_HV_DECREMENTER
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bne 2f
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@ -1303,7 +1310,7 @@ BEGIN_FTR_SECTION
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END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
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lbz r0, HSTATE_HOST_IPI(r13)
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cmpwi r0, 0
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beq 4f
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beq maybe_reenter_guest
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b guest_exit_cont
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3:
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/* If it's a hypervisor facility unavailable interrupt, save HFSCR */
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@ -1315,82 +1322,16 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
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14:
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/* External interrupt ? */
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cmpwi r12, BOOK3S_INTERRUPT_EXTERNAL
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bne+ guest_exit_cont
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/* External interrupt, first check for host_ipi. If this is
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* set, we know the host wants us out so let's do it now
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*/
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bl kvmppc_read_intr
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/*
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* Restore the active volatile registers after returning from
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* a C function.
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*/
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ld r9, HSTATE_KVM_VCPU(r13)
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li r12, BOOK3S_INTERRUPT_EXTERNAL
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/*
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* kvmppc_read_intr return codes:
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*
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* Exit to host (r3 > 0)
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* 1 An interrupt is pending that needs to be handled by the host
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* Exit guest and return to host by branching to guest_exit_cont
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*
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* 2 Passthrough that needs completion in the host
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* Exit guest and return to host by branching to guest_exit_cont
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* However, we also set r12 to BOOK3S_INTERRUPT_HV_RM_HARD
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* to indicate to the host to complete handling the interrupt
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*
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* Before returning to guest, we check if any CPU is heading out
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* to the host and if so, we head out also. If no CPUs are heading
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* check return values <= 0.
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*
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* Return to guest (r3 <= 0)
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* 0 No external interrupt is pending
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* -1 A guest wakeup IPI (which has now been cleared)
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* In either case, we return to guest to deliver any pending
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* guest interrupts.
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*
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* -2 A PCI passthrough external interrupt was handled
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* (interrupt was delivered directly to guest)
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* Return to guest to deliver any pending guest interrupts.
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*/
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cmpdi r3, 1
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ble 1f
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/* Return code = 2 */
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li r12, BOOK3S_INTERRUPT_HV_RM_HARD
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stw r12, VCPU_TRAP(r9)
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b guest_exit_cont
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1: /* Return code <= 1 */
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cmpdi r3, 0
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bgt guest_exit_cont
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/* Return code <= 0 */
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4: ld r5, HSTATE_KVM_VCORE(r13)
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lwz r0, VCORE_ENTRY_EXIT(r5)
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cmpwi r0, 0x100
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mr r4, r9
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blt deliver_guest_interrupt
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guest_exit_cont: /* r9 = vcpu, r12 = trap, r13 = paca */
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/* Save more register state */
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mfdar r6
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mfdsisr r7
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std r6, VCPU_DAR(r9)
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stw r7, VCPU_DSISR(r9)
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/* don't overwrite fault_dar/fault_dsisr if HDSI */
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cmpwi r12,BOOK3S_INTERRUPT_H_DATA_STORAGE
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beq mc_cont
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std r6, VCPU_FAULT_DAR(r9)
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stw r7, VCPU_FAULT_DSISR(r9)
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beq kvmppc_guest_external
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/* See if it is a machine check */
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cmpwi r12, BOOK3S_INTERRUPT_MACHINE_CHECK
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beq machine_check_realmode
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mc_cont:
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/* Or a hypervisor maintenance interrupt */
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cmpwi r12, BOOK3S_INTERRUPT_HMI
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beq hmi_realmode
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guest_exit_cont: /* r9 = vcpu, r12 = trap, r13 = paca */
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#ifdef CONFIG_KVM_BOOK3S_HV_EXIT_TIMING
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addi r3, r9, VCPU_TB_RMEXIT
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mr r4, r9
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@ -1821,24 +1762,6 @@ BEGIN_FTR_SECTION
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mtspr SPRN_DPDES, r8
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END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
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/* If HMI, call kvmppc_realmode_hmi_handler() */
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lwz r12, STACK_SLOT_TRAP(r1)
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cmpwi r12, BOOK3S_INTERRUPT_HMI
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bne 27f
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bl kvmppc_realmode_hmi_handler
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nop
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cmpdi r3, 0
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/*
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* At this point kvmppc_realmode_hmi_handler may have resync-ed
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* the TB, and if it has, we must not subtract the guest timebase
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* offset from the timebase. So, skip it.
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*
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* Also, do not call kvmppc_subcore_exit_guest() because it has
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* been invoked as part of kvmppc_realmode_hmi_handler().
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*/
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beq 30f
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27:
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/* Subtract timebase offset from timebase */
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ld r8, VCORE_TB_OFFSET_APPL(r5)
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cmpdi r8,0
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@ -1856,7 +1779,16 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
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addis r8,r8,0x100 /* if so, increment upper 40 bits */
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mtspr SPRN_TBU40,r8
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17: bl kvmppc_subcore_exit_guest
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17:
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/*
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* If this is an HMI, we called kvmppc_realmode_hmi_handler
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* above, which may or may not have already called
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* kvmppc_subcore_exit_guest. Fortunately, all that
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* kvmppc_subcore_exit_guest does is clear a flag, so calling
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* it again here is benign even if kvmppc_realmode_hmi_handler
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* has already called it.
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*/
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bl kvmppc_subcore_exit_guest
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nop
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30: ld r5,HSTATE_KVM_VCORE(r13)
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ld r4,VCORE_KVM(r5) /* pointer to struct kvm */
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@ -1910,6 +1842,67 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
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mtlr r0
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blr
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kvmppc_guest_external:
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/* External interrupt, first check for host_ipi. If this is
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* set, we know the host wants us out so let's do it now
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*/
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bl kvmppc_read_intr
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/*
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* Restore the active volatile registers after returning from
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* a C function.
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*/
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ld r9, HSTATE_KVM_VCPU(r13)
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li r12, BOOK3S_INTERRUPT_EXTERNAL
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/*
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* kvmppc_read_intr return codes:
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*
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* Exit to host (r3 > 0)
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* 1 An interrupt is pending that needs to be handled by the host
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* Exit guest and return to host by branching to guest_exit_cont
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*
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* 2 Passthrough that needs completion in the host
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* Exit guest and return to host by branching to guest_exit_cont
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* However, we also set r12 to BOOK3S_INTERRUPT_HV_RM_HARD
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* to indicate to the host to complete handling the interrupt
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*
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* Before returning to guest, we check if any CPU is heading out
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* to the host and if so, we head out also. If no CPUs are heading
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* check return values <= 0.
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*
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* Return to guest (r3 <= 0)
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* 0 No external interrupt is pending
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* -1 A guest wakeup IPI (which has now been cleared)
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* In either case, we return to guest to deliver any pending
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* guest interrupts.
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*
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* -2 A PCI passthrough external interrupt was handled
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* (interrupt was delivered directly to guest)
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* Return to guest to deliver any pending guest interrupts.
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*/
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cmpdi r3, 1
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ble 1f
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/* Return code = 2 */
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li r12, BOOK3S_INTERRUPT_HV_RM_HARD
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stw r12, VCPU_TRAP(r9)
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b guest_exit_cont
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1: /* Return code <= 1 */
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cmpdi r3, 0
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bgt guest_exit_cont
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/* Return code <= 0 */
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maybe_reenter_guest:
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ld r5, HSTATE_KVM_VCORE(r13)
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lwz r0, VCORE_ENTRY_EXIT(r5)
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cmpwi r0, 0x100
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mr r4, r9
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blt deliver_guest_interrupt
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b guest_exit_cont
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#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
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/*
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* Softpatch interrupt for transactional memory emulation cases
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@ -2685,13 +2678,7 @@ END_FTR_SECTION(CPU_FTR_TM | CPU_FTR_P9_TM_HV_ASSIST, 0)
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mr r9, r4
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cmpdi r3, 0
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bgt guest_exit_cont
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/* see if any other thread is already exiting */
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lwz r0,VCORE_ENTRY_EXIT(r5)
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cmpwi r0,0x100
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bge guest_exit_cont
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b kvmppc_cede_reentry /* if not go back to guest */
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b maybe_reenter_guest
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/* cede when already previously prodded case */
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kvm_cede_prodded:
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@ -2758,12 +2745,12 @@ machine_check_realmode:
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*/
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ld r11, VCPU_MSR(r9)
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rldicl. r0, r11, 64-MSR_HV_LG, 63 /* check if it happened in HV mode */
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bne mc_cont /* if so, exit to host */
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bne guest_exit_cont /* if so, exit to host */
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/* Check if guest is capable of handling NMI exit */
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ld r10, VCPU_KVM(r9)
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lbz r10, KVM_FWNMI(r10)
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cmpdi r10, 1 /* FWNMI capable? */
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beq mc_cont /* if so, exit with KVM_EXIT_NMI. */
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beq guest_exit_cont /* if so, exit with KVM_EXIT_NMI. */
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/* if not, fall through for backward compatibility. */
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andi. r10, r11, MSR_RI /* check for unrecoverable exception */
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@ -2776,6 +2763,21 @@ machine_check_realmode:
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bl kvmppc_msr_interrupt
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2: b fast_interrupt_c_return
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/*
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* Call C code to handle a HMI in real mode.
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* Only the primary thread does the call, secondary threads are handled
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* by calling hmi_exception_realmode() after kvmppc_hv_entry returns.
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* r9 points to the vcpu on entry
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*/
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hmi_realmode:
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lbz r0, HSTATE_PTID(r13)
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cmpwi r0, 0
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bne guest_exit_cont
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bl kvmppc_realmode_hmi_handler
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ld r9, HSTATE_KVM_VCPU(r13)
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li r12, BOOK3S_INTERRUPT_HMI
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b guest_exit_cont
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/*
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* Check the reason we woke from nap, and take appropriate action.
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* Returns (in r3):
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