From df709a296ef7c493a074609019b0e074cde5c0d0 Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Mon, 8 Oct 2018 16:30:52 +1100 Subject: [PATCH] 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 Reviewed-by: David Gibson Signed-off-by: Michael Ellerman --- arch/powerpc/kvm/book3s_hv_ras.c | 8 ++ arch/powerpc/kvm/book3s_hv_rmhandlers.S | 220 ++++++++++++++++---------------- 2 files changed, 119 insertions(+), 109 deletions(-) diff --git a/arch/powerpc/kvm/book3s_hv_ras.c b/arch/powerpc/kvm/book3s_hv_ras.c index b11043b..ee564b6 100644 --- a/arch/powerpc/kvm/book3s_hv_ras.c +++ b/arch/powerpc/kvm/book3s_hv_ras.c @@ -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; } diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index 5b2ae34..fc360b5 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -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 */ @@ -2777,6 +2764,21 @@ machine_check_realmode: 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): * 0 if nothing needs to be done -- 2.7.4